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Bertrand OC, Jiménez Lao M, Shelley SL, Wible JR, Williamson TE, Meng J, Brusatte SL. The virtual brain endocast of Trogosus (Mammalia, Tillodontia) and its relevance in understanding the extinction of archaic placental mammals. J Anat 2024; 244:1-21. [PMID: 37720992 PMCID: PMC10734658 DOI: 10.1111/joa.13951] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2023] [Revised: 08/29/2023] [Accepted: 08/29/2023] [Indexed: 09/19/2023] Open
Abstract
After successfully diversifying during the Paleocene, the descendants of the first wave of mammals that survived the end-Cretaceous mass extinction waned throughout the Eocene. Competition with modern crown clades and intense climate fluctuations may have been part of the factors leading to the extinction of these archaic groups. Why these taxa went extinct has rarely been studied from the perspective of the nervous system. Here, we describe the first virtual endocasts for the archaic order Tillodontia. Three species from the middle Eocene of North America were analyzed: Trogosus hillsii, Trogosus grangeri, and Trogosus castoridens. We made morphological comparisons with the plaster endocast of another tillodont, Tillodon fodiens, as well as groups potentially related to Tillodontia: Pantodonta, Arctocyonidae, and Cimolesta. Trogosus shows very little inter-specific variation with the only potential difference being related to the fusion of the optic canal and sphenorbital fissure. Many ancestral features are displayed by Trogosus, including an exposed midbrain, small neocortex, orbitotemporal canal ventral to rhinal fissure, and a broad circular fissure. Potential characteristics that could unite Tillodontia with Pantodonta, and Arctocyonidae are the posterior position of cranial nerve V3 exit in relation to the cerebrum and the low degree of development of the subarcuate fossa. The presence of large olfactory bulbs and a relatively small neocortex are consistent with a terrestrial lifestyle. A relatively small neocortex may have put Trogosus at risk when competing with artiodactyls for potentially similar resources and avoiding predation from archaic carnivorans, both of which are known to have had larger relative brain and neocortex sizes in the Eocene. These factors may have possibly exacerbated the extinction of Tillodontia, which showed highly specialized morphologies despite the increase in climate fluctuations throughout the Eocene, before disappearing during the middle Eocene.
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Affiliation(s)
- Ornella C Bertrand
- Institut Català de Paleontologia Miquel Crusafont, Universitat Autònoma de Barcelona, Edifici ICTA-ICP, Cerdanyola del Vallès, Barcelona, Spain
- School of GeoSciences, Grant Institute, University of Edinburgh, Edinburgh, Scotland, UK
| | - Marina Jiménez Lao
- School of GeoSciences, Grant Institute, University of Edinburgh, Edinburgh, Scotland, UK
| | - Sarah L Shelley
- School of GeoSciences, Grant Institute, University of Edinburgh, Edinburgh, Scotland, UK
- Section of Mammals, Carnegie Museum of Natural History, Pittsburgh, Pennsylvania, USA
| | - John R Wible
- Section of Mammals, Carnegie Museum of Natural History, Pittsburgh, Pennsylvania, USA
| | - Thomas E Williamson
- New Mexico Museum of Natural History and Science, Albuquerque, New Mexico, USA
| | - Jin Meng
- Division of Paleontology, American Museum of Natural History, New York, New York, USA
| | - Stephen L Brusatte
- School of GeoSciences, Grant Institute, University of Edinburgh, Edinburgh, Scotland, UK
- New Mexico Museum of Natural History and Science, Albuquerque, New Mexico, USA
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2
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Wible JR. The ear region of the Philippine flying lemur Cynocephalus volans (Placentalia, Dermoptera). Anat Rec (Hoboken) 2023; 306:2853-2871. [PMID: 36897245 DOI: 10.1002/ar.25174] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 01/23/2023] [Accepted: 01/25/2023] [Indexed: 03/11/2023]
Abstract
The placental order Dermoptera, which includes two extant species, the Philippine and Sunda flying lemurs, Cynocephalus volans and Galeopterus variegatus, respectively, is generally held to be the sister group of Primates. Yet, little has been reported on their cranial anatomy. Here, the anatomy of the ear region is described and illustrated for a juvenile and adult C. volans based on CT scans. The inclusion of a juvenile is essential as nearly all cranial sutures are fused in the adult. Soft tissues are reconstructed based on sectioned histological pre- and postnatal specimens previously reported by the author. Numerous unusual features are identified, including: a small parasphenoid beneath the basisphenoid, a tensor tympani fossa on the epitympanic wing of the squamosal, a cavum supracochleare for the geniculate ganglion of the facial nerve that is not enclosed in the petrosal bone, a secondary facial foramen between the petrosal and squamosal, a secondary posttemporal foramen leading to the primary one, a subarcuate fossa that is floored in part by a large contribution from the squamosal, a body of the incus larger than the head of the malleus, and a crus longum of the incus that lacks an osseous connection to the lenticular process. Documentation of the anatomy of the Philippine flying lemur ear region is an essential first step in morphological phylogenetic analyses where features of the basicranium are widely sampled.
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Affiliation(s)
- John R Wible
- Section of Mammals, Carnegie Museum of Natural History, Pittsburgh, Pennsylvania, USA
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3
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Maugoust J, Orliac MJ. Anatomical correlates and nomenclature of the chiropteran endocranial cast. Anat Rec (Hoboken) 2023; 306:2791-2829. [PMID: 37018745 DOI: 10.1002/ar.25206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Revised: 02/07/2023] [Accepted: 02/08/2023] [Indexed: 04/07/2023]
Abstract
Bats form a diverse group of mammals that are highly specialized in active flight and ultrasound echolocation. These specializations rely on adaptations that reflect on their morphoanatomy and have been tentatively linked to brain morphology and volumetry. Despite their small size and fragility, bat crania and natural braincase casts ("endocasts") have been preserved in the fossil record, which allows for investigating brain evolution and inferring paleobiology. Advances in imaging techniques have allowed virtual extraction of internal structures, assuming that the shape of the endocast reflects soft organ morphology. However, there is no direct correspondence between the endocast and internal structures because meninges and vascular tissues mark the inner braincase together with the brain they surround, resulting in a mosaic morphology of the endocast. The hypothesis suggesting that the endocast reflects the brain in terms of both external shape and volume has drastic implications when addressing brain evolution, but it has been rarely discussed. To date, only a single study addressed the correspondence between the brain and braincase in bats. Taking advantage of the advent of imaging techniques, we reviewed the anatomical, neuroanatomical, and angiological literature and compare this knowledge available on bat's braincase anatomy with anatomical observations using a sample of endocranial casts representing most modern bat families. Such comparison allows to propose a Chiroptera-scale nomenclature for future descriptions and comparisons among bat endocasts. Describing the imprints of the tissues surrounding the brain also allows to address to what extent brain features can be blurred or hidden (e.g., hypophysis, epiphysis, colliculi, flocculus). Furthermore, this approach encourages further study to formally test the proposed hypotheses.
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Affiliation(s)
- Jacob Maugoust
- Institut des Sciences de l'Evolution de Montpellier, département CHANGE, équipe Paléontologie, UMR 5554 Université de Montpellier, CNRS, IRD, EPHE, Place Eugène Bataillon, Montpellier Cedex 5, 34095, France
| | - Maeva Judith Orliac
- Institut des Sciences de l'Evolution de Montpellier, département CHANGE, équipe Paléontologie, UMR 5554 Université de Montpellier, CNRS, IRD, EPHE, Place Eugène Bataillon, Montpellier Cedex 5, 34095, France
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Mammalian Petrosals from the Upper Jurassic Morrison Formation (Utah, USA) Reveal Non-canonical Evolution of Middle and Inner Ear Characters. J MAMM EVOL 2021. [DOI: 10.1007/s10914-021-09586-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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5
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Le Verger K, González Ruiz LR, Billet G. Comparative anatomy and phylogenetic contribution of intracranial osseous canals and cavities in armadillos and glyptodonts (Xenarthra, Cingulata). J Anat 2021; 239:1473-1502. [PMID: 34275130 PMCID: PMC8602025 DOI: 10.1111/joa.13512] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2021] [Revised: 06/28/2021] [Accepted: 06/29/2021] [Indexed: 11/29/2022] Open
Abstract
The evolutionary history of the Cingulata, as for many groups, remains a highly debated topic to this day, particularly for one of their most emblematic representatives: the glyptodonts. There is no consensus among morphological and molecular phylogenies regarding their position within Cingulata. As demonstrated by recent works, the study of the internal anatomy constitutes a promising path for enriching morphological matrices for the phylogenetic study of armadillos. However, internal cranial anatomy remains understudied in the Cingulata. Here we explored and compared the anatomy of intracranial osseous canals and cavities in a diverse sample of extant and extinct cingulates, including the earliest well-preserved glyptodont crania. The virtual 3D reconstruction (using X-ray microtomography) of selected canals, that is, the nasolacrimal canal, the palatine canal, the sphenopalatine canal, the canal for the frontal diploic vein, the transverse canal, the orbitotemporal canal, the canal for the capsuloparietal emissary vein and the posttemporal canal, and alveolar cavities related to cranial vascularization, innervation or tooth insertion allowed us to compare the locations, trajectories, and shape of these structures and to discuss their potential interest for cingulate systematics. We tentatively reconstructed evolutionary scenarios for eight selected traits related to these structures in which glyptodonts often showed a close resemblance to pampatheres, to the genus Proeutatus, and/or to chlamyphorines. This latter pattern was partly congruent with recent molecular hypotheses, but more research is needed on these resemblances and on the potential effects of development and allometry on the observed variations. Overall, these comparisons have enabled us to highlight new anatomical variation that may be of great interest to further explore the evolutionary history of cingulates and the origins of glyptodonts on a morphological basis.
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Affiliation(s)
- Kévin Le Verger
- Museum national d’Histoire naturelleCentre de Recherche en Paléontologie – ParisUMR 7207 CR2P MNHN/CNRS/UPMCSorbonne UniversitésParisFrance
| | - Laureano R. González Ruiz
- Laboratorio de Investigaciones en Evolución y Biodiversidad (LIEB‐FCNyCS sede EsquelUNPSJB) y Centro de Investigaciones Esquel de Montaña y Estepa Patagónica (CIEMEP), CONICETUniversidad Nacional de La Patagonia San Juan Bosco (UNPSJB)ChubutArgentina
| | - Guillaume Billet
- Museum national d’Histoire naturelleCentre de Recherche en Paléontologie – ParisUMR 7207 CR2P MNHN/CNRS/UPMCSorbonne UniversitésParisFrance
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Shelley SL, Bertrand OC, Brusatte SL, Williamson TE. Petrosal Anatomy of the Paleocene Eutherian Mammal Deltatherium fundaminis (Cope, 1881). J MAMM EVOL 2021; 28:1161-1180. [PMID: 34483638 PMCID: PMC8406390 DOI: 10.1007/s10914-021-09568-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/01/2021] [Indexed: 12/04/2022]
Abstract
We describe the tympanic anatomy of the petrosal of Deltatherium fundaminis, an enigmatic Paleocene mammal based on cranial specimens recovered from New Mexico, U.S.A. Although the ear region of Deltatherium has previously been described, there has not been a comprehensive, well-illustrated contribution using current anatomical terminology. The dental and cranial anatomy of Deltatherium is a chimera, with morphological similarities to both ‘condylarth’ and ‘cimolestan’ taxa. As such, the phylogenetic relationships of this taxon have remained elusive since its discovery, and it has variably been associated with Arctocyonidae, Pantodonta and Tillodontia. The petrosal of Deltatherium is anteriorly bordered by an open space comprising a contiguous carotid opening and pyriform fenestra. The promontorium features both a small rostral tympanic process and small epitympanic wing but lacks well-marked sulci. A large ventral facing external aperture of the canaliculus cochleae is present and bordered posteriorly by a well-developed caudal tympanic process. The hiatus Fallopii opens on the ventral surface of the petrosal. The tegmen tympani is mediolaterally broad and anteriorly expanded, and its anterior margin is perforated by a foramen for the ramus superior of the stapedial artery. The tympanohyal is small but approximates the caudal tympanic process to nearly enclose the stylomastoid notch. The mastoid is widely exposed on the basicranium and bears an enlarged mastoid process, separate from the paraoccipital process. These new observations provide novel anatomical data corroborating previous hypotheses regarding the plesiomorphic eutherian condition but also reveal subtle differences among Paleocene eutherians that have the potential to help inform the phylogeny of Deltatherium.
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Affiliation(s)
- Sarah L Shelley
- School of GeoSciences, University of Edinburgh, Edinburgh, United Kingdom.,Carnegie Museum of Natural History, Pittsburgh, Pennsylvania United States of America
| | - Ornella C Bertrand
- School of GeoSciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Stephen L Brusatte
- School of GeoSciences, University of Edinburgh, Edinburgh, United Kingdom.,New Mexico Museum of Natural History and Science, Albuquerque, New Mexico United States of America
| | - Thomas E Williamson
- New Mexico Museum of Natural History and Science, Albuquerque, New Mexico United States of America
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MacPhee R, Del Pino SH, Kramarz A, Forasiepi AM, Bond M, Sulser RB. Cranial Morphology and Phylogenetic Relationships of Trigonostylops wortmani, an Eocene South American Native Ungulate. BULLETIN OF THE AMERICAN MUSEUM OF NATURAL HISTORY 2021. [DOI: 10.1206/0003-0090.449.1.1] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Affiliation(s)
- R.D.E. MacPhee
- Department of Mammalogy/Vertebrate Zoology and Richard Gilder Graduate School, American Museum of Natural History
| | | | - Alejandro Kramarz
- Sección Paleontología de Vertebrados, Museo Argentino de Ciencias Naturales Bernardino Rivadavia, CONICET, Buenos Aires, Argentina
| | | | - Mariano Bond
- Departamento Científico de Paleontología Vertebrados, Museo de La Plata, Paseo del Bosque s/n, 1900 La Plata, Argentina
| | - R. Benjamin Sulser
- Department of Mammalogy/Vertebrate Zoology and Richard Gilder Graduate School, American Museum of Natural History
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Harper T, Rougier GW. Petrosal morphology and cochlear function in Mesozoic stem therians. PLoS One 2019; 14:e0209457. [PMID: 31412094 PMCID: PMC6693738 DOI: 10.1371/journal.pone.0209457] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Accepted: 06/07/2019] [Indexed: 11/19/2022] Open
Abstract
Here we describe the bony anatomy of the inner ear and surrounding structures seen in three plesiomorphic crown mammalian petrosal specimens. Our study sample includes the triconodont Priacodon fruitaensis from the Upper Jurassic of North America, and two isolated stem therian petrosal specimens colloquially known as the Höövör petrosals, recovered from Aptian-Albian sediments in Mongolia. The second Höövör petrosal is here described at length for the first time. All three of these petrosals and a comparative sample of extant mammalian taxa have been imaged using micro-CT, allowing for detailed anatomical descriptions of the osteological correlates of functionally significant neurovascular features, especially along the abneural wall of the cochlear canal. The high resolution imaging provided here clarifies several hypotheses regarding the mosaic evolution of features of the cochlear endocast in early mammals. In particular, these images demonstrate that the membranous cochlear duct adhered to the bony cochlear canal abneurally to a secondary bony lamina before the appearance of an opposing primary bony lamina or tractus foraminosus. Additionally, while corroborating the general trend of reduction of venous sinuses and plexuses within the pars cochlearis seen in crownward mammaliaforms generally, the Höövör petrosals show the localized enlargement of a portion of the intrapetrosal venous plexus. This new vascular feature is here interpreted as the bony accommodation for the vein of cochlear aqueduct, a structure that is solely, or predominantly, responsible for the venous drainage of the cochlear apparatus in extant therians. Given that our fossil stem therian inner ear specimens appear to have very limited high-frequency capabilities, the development of these modern vascular features of the cochlear endocast suggest that neither the initiation or enlargement of the stria vascularis (a unique mammalian organ) was originally associated with the capacity for high-frequency hearing or precise sound-source localization.
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Affiliation(s)
- Tony Harper
- Center for Functional Anatomy and Evolution, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Guillermo W. Rougier
- Department of Anatomical Sciences and Neurobiology, University of Louisville, Louisville, Kentucky, United States of America
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Forasiepi AM, Macphee RD, Pino SHD. Caudal Cranium of Thylacosmilus atrox (Mammalia, Metatheria, Sparassodonta), a South American Predaceous Sabertooth. BULLETIN OF THE AMERICAN MUSEUM OF NATURAL HISTORY 2019. [DOI: 10.1206/0003-0090.433.1.1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Affiliation(s)
| | - Ross D.E. Macphee
- Department of Mammalogy, American Museum of Natural History, New York
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10
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Arnaudo ME, Toledo N, Soibelzon L, Bona P. Phylogenetic signal analysis in the basicranium of Ursidae (Carnivora, Mammalia). PeerJ 2019; 7:e6597. [PMID: 30891368 PMCID: PMC6422017 DOI: 10.7717/peerj.6597] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Accepted: 02/09/2019] [Indexed: 11/29/2022] Open
Abstract
Ursidae is a monophyletic group comprised of three subfamilies: Tremarctinae, Ursinae and Ailuropodinae, all of which have a rich geographical distribution. The phylogenetic relationships within the Ursidae group have been underexamined, especially regarding morphological traits such as the basicranium. Importantly, the basicranium is a highly complex region that covers a small portion of the skull, combining both structural and functional aspects that determine its morphology. Phylogenetic hypotheses of the Ursidae (including Tremarctinae) have been made based on morphological characters that considers skull, mandible and teeth features, while specific characters of the auditory region and basicranium have not been taken into account. To do this, we analyse the shape and size macroevolution of the basicranium of Ursidae, testing its morphological disparity in a phylogenetic context, which is quantified by means of the phylogenetic signal. We investigated phylogenetical autocorrelation by shape (depicted by Principal Components Analysis scores from previous published analyses) and basicranium size (depicted by centroid size, CS) using an orthonormal decomposition analysis and Abouheif C mean. The main advantages of these methods are that they rely exclusively on cladogram topology and do not require branch-length estimates. Also, an optimisation of the ancestral nodes was performed using TNT 1.5 software. In relation to the phylogenetic signal, both methods showed similar results: the presence of autocorrelation was detected in PC1 and PC2, while in PC3, PC4 and PC5 and in the size of the basicranium (CS), the absence of autocorrelation occurred. The most significant nodes (where there is autocorrelation) are the basal nodes 'Ursidae' and 'Ursinae-Tremarctinae'. Within this last group, distinctive basicranium morphology is observed, being more conservative in Tremarctinae than in Ursinae. The differences between these subfamilies could be related to historical events involving varying food and environmental preferences. The high phylogenetic signal in the node Tremarctinae probably indicates that the basicranium configuration of these bears was obtained early in their evolutionary history. Finally, our results of the basicranium and skull length ratios indicate that in Tremarctinae, the basicranium size was not determined by phylogeny but instead by other factors, such as adaptive responses to climatic changes and competition with other carnivores.
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Affiliation(s)
- María Eugenia Arnaudo
- División de Paleontología Vertebrados, Facultad de Ciencias Naturales y Museo-UNLP, La Plata, Buenos Aires, Argentina
- CONICET, Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina
| | - Néstor Toledo
- CONICET, Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina
- División Paleontología Vertebrados, Unidades de Investigación Anexo Museo, Facultad de Ciencias Naturales y Museo-UNLP, La Plata, Buenos Aires, Argentina
| | - Leopoldo Soibelzon
- CONICET, Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina
- Laboratorio de Morfología Evolutiva y Desarrollo (MORPHOS)-División de Paleontología Vertebrados, Facultad de Ciencias Naturales y Museo-UNLP, La Plata, Buenos Aires, Argentina
| | - Paula Bona
- CONICET, Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina
- División Paleontología Vertebrados, Unidades de Investigación Anexo Museo, Facultad de Ciencias Naturales y Museo-UNLP, La Plata, Buenos Aires, Argentina
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The osteology of Periptychus carinidens: A robust, ungulate-like placental mammal (Mammalia: Periptychidae) from the Paleocene of North America. PLoS One 2018; 13:e0200132. [PMID: 30020948 PMCID: PMC6051615 DOI: 10.1371/journal.pone.0200132] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Accepted: 06/20/2018] [Indexed: 11/19/2022] Open
Abstract
Periptychus is the archetypal genus of Periptychidae, a clade of prolific Paleocene 'condylarth' mammals from North America that were among the first placental mammals to radiate after the end-Cretaceous extinction, remarkable for their distinctive dental anatomy. A comprehensive understanding of the anatomy of Periptychus has been hindered by a lack of cranial and postcranial material and only cursory description of existing material. We comprehensively describe the cranial, dental and postcranial anatomy of Periptychus carinidens based on new fossil material from the early Paleocene (Torrejonian) of New Mexico, USA. The cranial anatomy of Periptychus is broadly concurrent with the inferred plesiomorphic eutherian condition, albeit more robust in overall construction. The rostrum is moderately elongate with no constriction, the facial region is broad, and the braincase is small with a well-exposed mastoid on the posterolateral corner and tall sagittal and nuchal crests. The dentition of Periptychus is characterized by strongly crenulated enamel, enlarged upper and lower premolars with a tall centralised paracone/protoconid. The postcranial skeleton of Periptychus is that of a robust, medium-sized (~20 Kg) stout-limbed animal that was incipiently mediportal and adopted a plantigrade stance. The structure of the fore- and hindlimb of Periptychus corresponds to that of a typically terrestrial mammal, while morphological features of the forelimb such as the low tubercles of the humerus, long and prominent deltopectoral crest, pronounced medial epicondyle, and hemispherical capitulum indicate some scansorial and/or fossorial ability. Most striking is the strongly dorsoplantarly compressed astragalus of Periptychus, which in combination with the distal crus and calcaneal morphology indicates a moderately mobile cruropedal joint. The anatomy of Periptychus is unique and lacks any extant analogue; it combines a basic early placental body plan with numerous unique specializations in its dental, cranial and postcranial anatomy that exemplify the ability of mammals to adapt and evolve following catastrophic environmental upheaval.
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12
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Kuchinka J. The Stapedial Artery in the Mongolian Gerbil (
Meriones unguiculatus
). Anat Rec (Hoboken) 2018; 301:1131-1137. [DOI: 10.1002/ar.23801] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Revised: 11/16/2017] [Accepted: 12/01/2017] [Indexed: 12/27/2022]
Affiliation(s)
- Jacek Kuchinka
- Department of Comparative Anatomy, Institute of BiologyJan Kochanowski University in Kielce, 15 Swietokrzyska St, 25‐406Kielce Poland
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13
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New Virtual Endocasts of Eocene Ischyromyidae and Their Relevance in Evaluating Neurological Changes Occurring Through Time in Rodentia. J MAMM EVOL 2018. [DOI: 10.1007/s10914-017-9425-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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14
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Laaß M, Schillinger B, Kaestner A. What did the "Unossified zone" of the non-mammalian therapsid braincase house? J Morphol 2017. [PMID: 28621458 DOI: 10.1002/jmor.20583] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Most nonmammalian synapsids possess a mid-dorsal depression in the brain cavity known as the "unossified zone." It remains obscure which structures this zone contained, and, as candidates, the vermis of the cerebellum, the superior sagittal sinus, a junction of several blood vessels, the pineal gland or other midbrain structures were considered. Neutron tomography of a skull of Diictodon feliceps (Therapsida, Anomodontia) revealed some clear impressions of canals in this region of the brain cavity. Furthermore, the prootic sinus probably ran on the internal surface of the pila antotica and had a similar course in anomodonts as it has been proposed for cynodonts and Mesozoic mammals. Comparisons with the vascular systems of nonmammalian synapsids and mammals suggest that the unossified zone is best interpreted as a terminal chamber of the anterior segment of the medial head vein, which housed the junction of the superior sagittal sinus and the transverse sinuses. Consequently, the system of cranial vessels in Diictodon reveals a partial division of the medial head vein system into an anterior and a posterior segment at an early stage of synapsid evolution, which is consistent with the well-known common pattern of early ontogenetic development in amniotes. J. Morphol., 2017. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Michael Laaß
- Faculty of Biology, Department of General Zoology, University of Duisburg-Essen, Universitätsstr. 5, Essen, D-45117, Germany
| | - Burkhard Schillinger
- Heinz Maier-Leibnitz Centre and Faculty for Physics E21, Technische Universität München, Lichtenbergstraße 1, Garching, D-85747, Germany
| | - Anders Kaestner
- Neutron Imaging and Activation Group, Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institute, Villigen, PSI, CH-5232, Switzerland
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Bertrand OC, Amador‐Mughal F, Silcox MT. Virtual endocast of the early Oligocene Cedromus wilsoni (Cedromurinae) and brain evolution in squirrels. J Anat 2017; 230:128-151. [PMID: 27580644 PMCID: PMC5192888 DOI: 10.1111/joa.12537] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/19/2016] [Indexed: 01/21/2023] Open
Abstract
Extant squirrels exhibit extensive variation in brain size and shape, but published endocranial data for living squirrels are limited, and no study has ever examined brain evolution in Sciuridae from the perspective of the fossil record to understand how this diversity emerged. We describe the first virtual endocast for a fossil sciurid, Cedromus wilsoni, which is known from a complete cranium from Wyoming (Orellan, Oligocene), and make comparisons to a diverse sample of virtual endocasts for living sciurids (N = 20). The virtual endocasts were obtained from high-resolution X-ray micro-computed tomography data. Comparisons were also made with endocasts of extinct ischyromyid rodents, the most primitive rodents known from an endocranial record, which provide the opportunity to study the neuroanatomical changes occurring near the base of Sciuridae. The encephalization quotient of C. wilsoni is higher than that of Ischyromys typus from the same epoch, and falls within the range of modern terrestrial squirrel variation, but below the range of extant scansorial, arboreal and gliding sciurids when using cheek-tooth area for the estimation of body mass. In a principal components analysis, the shape of the endocast of C. wilsoni is found to be intermediate between that of primitive fossil taxa and the modern sample. Cedromus wilsoni has a more expanded neocortical surface area, especially the caudal region of the cerebrum, compared with ischyromyid rodents. Furthermore, C. wilsoni had proportionally larger paraflocculi and a more complex cerebellar morphology compared with ischyromyid rodents. These neurological differences may be associated with improvements in vision, although it is worth noting that the size of the parts of the brain most directly involved with vision [the rostral (superior) colliculi and the primary visual cortex] cannot be directly assessed on endocasts. The changes observed could also relate to balance and limb coordination. Ultimately, the available evidence suggests that early squirrels were more agile and visually oriented animals compared with more primitive rodents, which may relate to the process of becoming arboreal. Extant sciurids have an even more expanded neocortical surface area, while exhibiting proportionally smaller paraflocculi, compared with C. wilsoni. This suggests that the neocortex may continue increasing in size in more recent sciurid rodents in relation to other factors than arboreality. Despite the fact that both Primates and Rodentia exhibit neocortical expansion through time, since the adoption of arboreality preceded major increases in the neocortex in Primates, those neurological changes may be related to different ecological factors, underlining the complexity of the inter-relationship between time and ecology in shaping the brain in even closely related clades.
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Affiliation(s)
- Ornella C. Bertrand
- Department of AnthropologyUniversity of Toronto ScarboroughTorontoOntarioCanada
| | | | - Mary T. Silcox
- Department of AnthropologyUniversity of Toronto ScarboroughTorontoOntarioCanada
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Boyer DM, Kirk EC, Silcox MT, Gunnell GF, Gilbert CC, Yapuncich GS, Allen KL, Welch E, Bloch JI, Gonzales LA, Kay RF, Seiffert ER. Internal carotid arterial canal size and scaling in Euarchonta: Re-assessing implications for arterial patency and phylogenetic relationships in early fossil primates. J Hum Evol 2016; 97:123-44. [DOI: 10.1016/j.jhevol.2016.06.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Revised: 06/03/2016] [Accepted: 06/04/2016] [Indexed: 01/31/2023]
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Forasiepi AM, MacPhee RDE, Del Pino SH, Schmidt GI, Amson E, Grohé C. Exceptional Skull of Huayqueriana (Mammalia, Litopterna, Macraucheniidae) From the Late Miocene of Argentina: Anatomy, Systematics, and Paleobiological Implications. BULLETIN OF THE AMERICAN MUSEUM OF NATURAL HISTORY 2016. [DOI: 10.1206/0003-0090-404.1.1] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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18
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Martínez G, Dozo MT, Gelfo JN, Marani H. Cranial Morphology of the Late Oligocene Patagonian Notohippid Rhynchippus equinus Ameghino, 1897 (Mammalia, Notoungulata) with Emphases in Basicranial and Auditory Region. PLoS One 2016; 11:e0156558. [PMID: 27232883 PMCID: PMC4883762 DOI: 10.1371/journal.pone.0156558] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2015] [Accepted: 05/16/2016] [Indexed: 11/18/2022] Open
Abstract
"Notohippidae" is a probably paraphyletic family of medium sized notoungulates with complete dentition and early tendency to hypsodonty. They have been recorded from early Eocene to early Miocene, being particularly diverse by the late Oligocene. Although Rhynchippus equinus Ameghino is one of the most frequent notohippids in the fossil record, there are scarce data about cranial osteology other than the classical descriptions which date back to the early last century. In this context, we describe the exceptionally preserved specimen MPEF PV 695 (based on CT scanning technique and 3D reconstruction) with the aim of improving our knowledge of the species, especially regarding auditory region (petrosal, tympanic and surrounding elements), sphenoidal and occipital complexes. Besides a modular description of the whole skull, osteological correlates identified on the basicranium are used to infer some soft-tissue elements, especially those associated with vessels that supply the head, mainly intracranially. One of the most informative elements was the petrosal bone, whose general morphology matches that expected for a toxodont. The endocranial surface, together with the surrounding parietal, basisphenoid, occipital, and squamosal, enabled us to propose the location and communication of main venous sinuses of the lateral head wall (temporal, inferior and sigmoid sinuses), whereas the tympanic aspect and the identification of a posterior carotid artery canal provided strong evidence in support of an intratympanic course of the internal carotid artery, a controversial issue among notoungulates. Regarding the arrangement of tympanic and paratympanic spaces, the preservation of the specimen allowed us to appreciate the three connected spaces that constitute a heavily pneumatized middle ear; the epitympanic sinus, the tympanic cavity itself, and the ventral expansion of the tympanic cavity through the notably inflated bullae. We hope this study stimulates further inquires and provides potentially informative data for future research involving other representatives of the order.
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Affiliation(s)
- Gastón Martínez
- Instituto Patagónico de Geología y Paleontología, Centro Nacional Patagónico, CONICET, Puerto Madryn, Chubut, Argentina
- Facultad de Ciencias Exactas Físicas y Naturales, Universidad Nacional de Córdoba, Córdoba, Argentina
- * E-mail:
| | - María Teresa Dozo
- Instituto Patagónico de Geología y Paleontología, Centro Nacional Patagónico, CONICET, Puerto Madryn, Chubut, Argentina
| | - Javier N. Gelfo
- División Paleontología Vertebrados, Museo de la Plata, CONICET, La Plata, Buenos Aires, Argentina
- Facultad de Ciencias Naturales y Museo, Universidad Nacional de La Plata, La Plata, Buenos Aires, Argentina
| | - Hernán Marani
- Facultad de Ciencias Naturales, Universidad Nacional de la Patagonia San Juan Bosco, Puerto Madryn, Chubut, Argentina
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Brocklehurst RJ, Crumpton N, Button E, Asher RJ. Jaw anatomy of Potamogale velox (Tenrecidae, Afrotheria) with a focus on cranial arteries and the coronoid canal in mammals. PeerJ 2016; 4:e1906. [PMID: 27114870 PMCID: PMC4841219 DOI: 10.7717/peerj.1906] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Accepted: 03/16/2016] [Indexed: 11/20/2022] Open
Abstract
Afrotheria is a strongly supported clade within placental mammals, but morphological synapomorphies for the entire group have only recently come to light. Soft tissue characters represent an underutilized source of data for phylogenetic analysis, but nonetheless provide features shared by some or all members of Afrotheria. Here, we investigate the developmental anatomy of Potamogale velox (Tenrecidae) with histological and computerized tomographic data at different ontogenetic ages, combined with osteological data from other mammals, to investigate patterns of cranial arterial supply and the distribution of the coronoid canal. Potamogale is atypical among placental mammals in exhibiting a small superior stapedial artery, a primary supply of the posterior auricular by the posterior stapedial artery, and the development of vascular plexuses (possibly with relevance for heat exchange) in the posterior and dorsal regions of its neck. In addition, the posterior aspect of Meckel's cartilage increases its medial deflection in larger embryonic specimens as the mandibular condyle extends mediolaterally during embryogenesis. We also map the distribution of the coronoid canal across mammals, and discuss potential confusion of this feature with alveoli of the posterior teeth. The widespread distribution of the coronoid canal among living and fossil proboscideans, sirenians, and hyracoids supports previous interpretations that a patent coronoid canal is a synapomorphy of paenungulates, but not afrotherians as a whole.
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Affiliation(s)
- Robert J Brocklehurst
- Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom; Department of Zoology, University of Cambridge, Cambridge, United Kingdom
| | - Nick Crumpton
- Department of Zoology, University of Cambridge, Cambridge, United Kingdom; Research Department of Cell & Developmental Biology, University College London, United Kingdom
| | - Evie Button
- Department of Zoology, University of Cambridge , Cambridge , United Kingdom
| | - Robert J Asher
- Department of Zoology, University of Cambridge , Cambridge , United Kingdom
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Bertrand OC, Amador-Mughal F, Silcox MT. Virtual endocasts of Eocene Paramys (Paramyinae): oldest endocranial record for Rodentia and early brain evolution in Euarchontoglires. Proc Biol Sci 2016; 283:20152316. [PMID: 26817776 PMCID: PMC4795019 DOI: 10.1098/rspb.2015.2316] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Accepted: 01/07/2016] [Indexed: 11/12/2022] Open
Abstract
Understanding the pattern of brain evolution in early rodents is central to reconstructing the ancestral condition for Glires, and for other members of Euarchontoglires including Primates. We describe the oldest virtual endocasts known for fossil rodents, which pertain to Paramys copei (Early Eocene) and Paramys delicatus (Middle Eocene). Both specimens of Paramys have larger olfactory bulbs and smaller paraflocculi relative to total endocranial volume than later occurring rodents, which may be primitive traits for Rodentia. The encephalization quotients (EQs) of Pa. copei and Pa. delicatus are higher than that of later occurring (Oligocene) Ischyromys typus, which contradicts the hypothesis that EQ increases through time in all mammalian orders. However, both species of Paramys have a lower relative neocortical surface area than later rodents, suggesting neocorticalization occurred through time in this Order, although to a lesser degree than in Primates. Paramys has a higher EQ but a lower neocortical ratio than any stem primate. This result contrasts with the idea that primates were always exceptional in their degree of overall encephalization and shows that relative brain size and neocortical surface area do not necessarily covary through time. As such, these data contradict assumptions made about the pattern of brain evolution in Euarchontoglires.
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Affiliation(s)
- Ornella C Bertrand
- Department of Anthropology, University of Toronto Scarborough, Toronto, Ontario, Canada M1C 1A4
| | - Farrah Amador-Mughal
- Department of Anthropology, University of Toronto Scarborough, Toronto, Ontario, Canada M1C 1A4
| | - Mary T Silcox
- Department of Anthropology, University of Toronto Scarborough, Toronto, Ontario, Canada M1C 1A4
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Crumpton N, Kardjilov N, Asher RJ. Convergence vs. Specialization in the ear region of moles (Mammalia). J Morphol 2015; 276:900-14. [PMID: 25858660 DOI: 10.1002/jmor.20391] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2014] [Revised: 03/03/2015] [Accepted: 03/10/2015] [Indexed: 11/05/2022]
Abstract
We investigated if and how the inner ear region undergoes similar adaptations in small, fossorial, insectivoran-grade mammals, and found a variety of inner ear phenotypes. In our sample, afrotherian moles (Chrysochloridae) and the marsupial Notoryctes differ from most other burrowing mammals in their relatively short radii of semicircular canal curvature; chrysochlorids and fossorial talpids share a relatively long interampullar width. Chrysochlorids are unique in showing a highly coiled cochlea with nearly four turns. Extensive cochlear coiling may reflect their greater ecological dependence on low frequency auditory cues compared to talpids, tenrecids, and the marsupial Notoryctes. Correspondingly, the lack of such extensive coiling in the inner ear of other fossorial species may indicate a greater reliance on other senses to enable their fossorial lifestyle, such as tactile sensation from vibrissae and Eimer's organs. The reliance of chrysochlorids on sound is evident in the high degree of coiling and in the diversity of its mallear types, and may help explain the lack of any semiaquatic members of that group. The simplest mallear types among chrysochlorids are not present in the basal-most members of that clade, but all extant chrysochlorids investigated to date exhibit extensive cochlear coiling. The chrysochlorid ear region thus exhibits mosaic evolution; our data suggest that extensive coiling evolved in chrysochlorids prior to and independently of diversification in middle ear ossicle size and shape.
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Affiliation(s)
- Nick Crumpton
- Department of Zoology, University of Cambridge, Downing Street, CB2 3EJ, UK.,Natural History Museum, Cromwell Road, London, SW7 5BD, UK
| | - Nikolay Kardjilov
- Helmholtz-Zentrum Berlin, Hahn-Meitner-Platz 1, D-14109, Berlin, Germany
| | - Robert J Asher
- Department of Zoology, University of Cambridge, Downing Street, CB2 3EJ, UK
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Frąckowiak H, Dębiński D, Komosa M, Zdun M. The arterial circle of the brain, its branches and connections in selected representatives of the Antilopinae. J Morphol 2015; 276:766-71. [PMID: 25694115 DOI: 10.1002/jmor.20377] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2014] [Revised: 01/19/2015] [Accepted: 01/25/2015] [Indexed: 11/09/2022]
Abstract
The arterial circle of the brain, that is, the circle of Willis, and its branches in ruminants have been chiefly described in farm animals and only in selected wild species. In view of the deficit of information about this vascular region in numerous other species of the Ruminantia, the arteries of the encephalic base were analyzed in five antelope species representing different genera of the Bovidae, Antilopinae. Specimens of the following species were examined: springbuck (Antidorcas marsupialis), blackbuck (Antilope cervicapra), dik-dik (Madoqua kirkii), saiga (Saiga tatarica), and oribi (Ourebia ourebi). Post-autopsy material received from domestic zoological gardens was used to inject the bilateral common carotid arteries with a stained acetone solution of vinyl superchloride. When the material was polymerized, the specimens were macerated enzymatically. The process resulted in casts of arteries of the head and encephalic base on a skeletal scaffold. The investigations revealed that the bilateral components of the arterial circle of the brain, that is, the rostral cerebral artery and caudal communicating artery, arose from the division of the intracranial segment of the internal carotid artery, which emerges from the rostral epidural rete mirabile. The extracranial segment of the internal carotid artery was obliterated. In consequence of this process, the blood reaches the brain chiefly from the maxillary artery. The research proved that the arteries of the encephalic base in the Antilopinae are most similar to the vessels described in antelopes of Tragelaphus, Taurotragus, and Boselaphus genera and small domestic ruminants. However, they are different from the arterial pattern of the encephalic base in bovines and other species classified as the Bovini.
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Affiliation(s)
- Hieronim Frąckowiak
- Department of Anatomy of Animals, Poznan University of Life Sciences, PL-60-625, Poznań, Poland
| | - Dariusz Dębiński
- Department of Anatomy of Animals, Poznan University of Life Sciences, PL-60-625, Poznań, Poland
| | - Marcin Komosa
- Department of Anatomy of Animals, Poznan University of Life Sciences, PL-60-625, Poznań, Poland
| | - Maciej Zdun
- Department of Anatomy of Animals, Poznan University of Life Sciences, PL-60-625, Poznań, Poland
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Billet G, de Muizon C, Schellhorn R, Ruf I, Ladevèze S, Bergqvist L. Petrosal and inner ear anatomy and allometry amongst specimens referred to Litopterna (Placentalia). Zool J Linn Soc 2015. [DOI: 10.1111/zoj.12219] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Guillaume Billet
- Steinmann-Institut für Geologie; Mineralogie und Paläontologie; Rheinische Friedrich-Wilhelms-Universität Bonn; Nussallee 8 53115 Bonn Germany
- CR2P - UMR 7207 CNRS; MNHN; Univ Paris 06 - Muséum national d'Histoire naturelle; 8 rue Buffon CP 38 75005 Paris France
| | - Christian de Muizon
- CR2P - UMR 7207 CNRS; MNHN; Univ Paris 06 - Muséum national d'Histoire naturelle; 8 rue Buffon CP 38 75005 Paris France
| | - Rico Schellhorn
- Steinmann-Institut für Geologie; Mineralogie und Paläontologie; Rheinische Friedrich-Wilhelms-Universität Bonn; Nussallee 8 53115 Bonn Germany
| | - Irina Ruf
- Steinmann-Institut für Geologie; Mineralogie und Paläontologie; Rheinische Friedrich-Wilhelms-Universität Bonn; Nussallee 8 53115 Bonn Germany
- Senckenberg Forschungsinstitut und Naturmuseum Frankfurt; Abteilung Paläoanthropologie und Messelforschung; Senckenberganlage 25 60325 Frankfurt am Main Germany
| | - Sandrine Ladevèze
- CR2P - UMR 7207 CNRS; MNHN; Univ Paris 06 - Muséum national d'Histoire naturelle; 8 rue Buffon CP 38 75005 Paris France
| | - Lilian Bergqvist
- Avenida Athos da Silveira Ramos; 274, bloco G; Centro de Ciências Matemáticas e da Natureza; Universidade Federal do Rio de Janeiro; Rio de Janeiro 21941-916 Brasil
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Benoit J, Crumpton N, Merigeaud S, Tabuce R. Petrosal and Bony Labyrinth Morphology Supports Paraphyly of Elephantulus Within Macroscelididae (Mammalia, Afrotheria). J MAMM EVOL 2013. [DOI: 10.1007/s10914-013-9234-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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25
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Persistent stapedial arteries in human: from phylogeny to surgical consequences. Surg Radiol Anat 2013; 35:883-91. [DOI: 10.1007/s00276-013-1127-z] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2013] [Accepted: 04/22/2013] [Indexed: 10/26/2022]
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Rougier GW, Wible JR, Beck RMD, Apesteguía S. The Miocene mammal Necrolestes demonstrates the survival of a Mesozoic nontherian lineage into the late Cenozoic of South America. Proc Natl Acad Sci U S A 2012; 109:20053-8. [PMID: 23169652 PMCID: PMC3523863 DOI: 10.1073/pnas.1212997109] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The early Miocene mammal Necrolestes patagonensis from Patagonia, Argentina, was described in 1891 as the only known extinct placental "insectivore" from South America (SA). Since then, and despite the discovery of additional well-preserved material, the systematic status of Necrolestes has remained in flux, with earlier studies leaning toward placental affinities and more recent ones endorsing either therian or specifically metatherian relationships. We have further prepared the best-preserved specimens of Necrolestes and compared them with newly discovered nontribosphenic Mesozoic mammals from Argentina; based on this, we conclude that Necrolestes is related neither to marsupials nor placentals but is a late-surviving member of the recently recognized nontherian clade Meridiolestida, which is currently known only from SA. This conclusion is supported by a morphological phylogenetic analysis that includes a broad sampling of therian and nontherian taxa and that places Necrolestes within Meridiolestida. Thus, Necrolestes is a remnant of the highly endemic Mesozoic fauna of nontribosphenic mammals in SA and extends the known record of meridiolestidans by almost 45 million years. Together with other likely relictual mammals from earlier in the Cenozoic of SA and Antarctica, Necrolestes demonstrates the ecological diversity of mammals and the mosaic pattern of fauna replacement in SA during the Cenozoic. In contrast to northern continents, the Cenozoic faunal history of SA was characterized by a long period of interaction between endemic mammalian lineages of Mesozoic origin and metatherian and eutherian lineages that probably dispersed to SA during the latest Cretaceous or earliest Paleocene.
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Affiliation(s)
- Guillermo W Rougier
- Department of Anatomical Sciences and Neurobiology, University of Louisville, Louisville, KY 40202, USA.
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LUO ZHEXI, RUF IRINA, MARTIN THOMAS. The petrosal and inner ear of the Late Jurassic cladotherian mammalDryolestes leiriensisand implications for ear evolution in therian mammals. Zool J Linn Soc 2012. [DOI: 10.1111/j.1096-3642.2012.00852.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Ekdale EG. Morphological variation in the ear region of pleistocene elephantimorpha (Mammalia, Proboscidea) from central Texas. J Morphol 2011; 272:452-64. [PMID: 21284018 DOI: 10.1002/jmor.10924] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2010] [Revised: 09/01/2010] [Accepted: 09/30/2010] [Indexed: 11/07/2022]
Abstract
A large sample of isolated elephantimorph petrosal bones was recovered from Pleistocene deposits in Friesenhahn Cave, Bexar County, Texas. Morphology of the middle and inner ear of the elephantimorphs is described and variation within the sample is identified. Observed variations occur in the stapedial ratio, morphology of the aquaeductus Fallopii, and connection of the crista interfenestralis to the tympanohyal on the posterior portion of the petrosal to form a foramen for passage of the stapedius muscle. The morphology of the aquaeductus Fallopii supports an ontogenetic explanation for some variation, and a sequence of ossification surrounding the aquaeductus Fallopii, from the anterior end of the canal to the posterior, is hypothesized. The stapedial ratio varies to a high degree across the sample, and such variation should be considered when the ratio is used in phylogenetic analyses. Within the inner ear, the absence of the secondary lamina suggests evolution of low-frequency hearing in extinct proboscideans, which is known for extant elephants. The morphology of the petrosals from Friesenhahn Cave is compared to published descriptions of the ear regions of other extinct proboscideans, and the distribution and evolution of morphologic characters are discussed. J. Morphol., 2011. © 2011 Wiley-Liss, Inc.
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Affiliation(s)
- Eric G Ekdale
- Department of Geological Sciences, Jackson School of Geological Sciences, The University of Texas at Austin, Austin, Texas 78712, USA.
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SILCOX MARYT, BLOCH JONATHANI, BOYER DOUGM, HOUDE PETER. Cranial anatomy of Paleocene and Eocene Labidolemur kayi (Mammalia: Apatotheria), and the relationships of the Apatemyidae to other mammals. Zool J Linn Soc 2010. [DOI: 10.1111/j.1096-3642.2009.00614.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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LADEVÈZE SANDRINE, DE MUIZON CHRISTIAN. Evidence of early evolution of Australidelphia (Metatheria, Mammalia) in South America: phylogenetic relationships of the metatherians from the Late Palaeocene of Itaboraí (Brazil) based on teeth and petrosal bones. Zool J Linn Soc 2010. [DOI: 10.1111/j.1096-3642.2009.00577.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Silcox MT, Benham AE, Bloch JI. Endocasts of Microsyops (Microsyopidae, Primates) and the evolution of the brain in primitive primates. J Hum Evol 2010; 58:505-21. [PMID: 20444495 DOI: 10.1016/j.jhevol.2010.03.008] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2009] [Revised: 03/18/2010] [Accepted: 03/23/2010] [Indexed: 11/24/2022]
Abstract
We describe a virtual endocast produced from ultra high resolution X-ray computed tomography (CT) data for the microsyopid, Microsyops annectens (middle Eocene, Wyoming). It is the most complete and least distorted endocast known for a plesiadapiform primate and because of the relatively basal position of Microsyopidae, has particular importance to reconstructing primitive characteristics for Primates. Cranial capacity is estimated at 5.9 cm(3), yielding encephalization quotients (EQ) of 0.26-0.39 (Jerison's equation) and 0.32-0.52 (Eisenberg's equation), depending on the body mass estimate. Even the lowest EQ estimate for M. annectens is higher than that for Plesiadapis cookei, while the range of estimates overlaps with that of Ignacius graybullianus and with the lower end of the range of estimates for fossil euprimates. As in other plesiadapiforms, the olfactory bulbs of M. annectens are large. The cerebrum does not extend onto the cerebellum or form a ventrally protruding temporal lobe with a clear temporal pole, suggesting less development of the visual sense and a greater emphasis on olfaction than in euprimates. Contrasts between the virtual endocast of M. annectens, and both a natural endocast of the same species and a partial endocast from the earlier-occurring Microsyops sp., cf. Microsyops elegans, suggest that the coverage of the caudal colliculi by the cerebrum evolved within the Microsyops lineage. This implies that microsyopids expanded their cerebra and perhaps evolved an improved visual sense independent of euprimates. With a growing body of data on the morphology of the brain in primitive primates, it is becoming clear that many of the characteristics of the brain common to euprimates evolved after the divergence of stem primates from other euarchontans and likely in parallel in different lineages. These new data suggest a different model for the ancestors of euprimates than has been assumed based on the anatomy of the brain in visually specialized diurnal tree shrews.
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Affiliation(s)
- Mary T Silcox
- Department of Anthropology, University of Winnipeg, 515 Portage Avenue, Winnipeg, MB R3B 2E9, Canada.
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32
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Forasiepi AM, Rougier GW. Additional data on early Paleocene metatherians (Mammalia) from Punta Peligro (Salamanca Formation, Argentina): comments based on petrosal morphology. J ZOOL SYST EVOL RES 2009. [DOI: 10.1111/j.1439-0469.2008.00519.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Wible JR. The Ear Region of the Pen-tailed Treeshrew, Ptilocercus lowii Gray, 1848 (Placentalia, Scandentia, Ptilocercidae). J MAMM EVOL 2009. [DOI: 10.1007/s10914-009-9116-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Cranial Morphology of a Pantolestid Eutherian Mammal from the Eocene Bridger Formation, Wyoming, USA: Implications for Relationships and Habitat. J MAMM EVOL 2007. [DOI: 10.1007/s10914-007-9055-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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LADEVÈZE SANDRINE. Petrosal bones of metatherian mammals from the Late Palaeocene of Itaboraí (Brazil), and a cladistic analysis of petrosal features in metatherians. Zool J Linn Soc 2007. [DOI: 10.1111/j.1096-3642.2007.00282.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Giannini NP, Wible JR, Simmons NB. On the Cranial Osteology of Chiroptera. I. Pteropus (Megachiroptera: Pteropodidae). BULLETIN OF THE AMERICAN MUSEUM OF NATURAL HISTORY 2006. [DOI: 10.1206/0003-0090(2006)295[0001:otcooc]2.0.co;2] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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GEISLER JONATHANH, SANDERS ALBERTE, LUO ZHEXI. A New Protocetid Whale (Cetacea: Archaeoceti) from the Late Middle Eocene of South Carolina. AMERICAN MUSEUM NOVITATES 2005. [DOI: 10.1206/0003-0082(2005)480[0001:anpwca]2.0.co;2] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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WIBLE JOHNR, NOVACEK MICHAELJ, ROUGIER GUILLERMOW. NEW DATA ON THE SKULL AND DENTITION IN THE MONGOLIAN LATE CRETACEOUS EUTHERIAN MAMMAL ZALAMBDALESTES. BULLETIN OF THE AMERICAN MUSEUM OF NATURAL HISTORY 2004. [DOI: 10.1206/0003-0090(2004)281<0001:ndotsa>2.0.co;2] [Citation(s) in RCA: 95] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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MENG JIN, HU YAOMING, LI CHUANKUI. THE OSTEOLOGY OF RHOMBOMYLUS (MAMMALIA, GLIRES): IMPLICATIONS FOR PHYLOGENY AND EVOLUTION OF GLIRES. BULLETIN OF THE AMERICAN MUSEUM OF NATURAL HISTORY 2003. [DOI: 10.1206/0003-0090(2003)275<0001:toormg>2.0.co;2] [Citation(s) in RCA: 110] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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TING SUYIN, MENG JIN, McKENNA MALCOLMC, LI CHUANKUEI. The Osteology of Matutinia (Simplicidentata, Mammalia) and Its Relationship to Rhombomylus. AMERICAN MUSEUM NOVITATES 2002. [DOI: 10.1206/0003-0082(2002)371<0001:toomsm>2.0.co;2] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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SANCHEZ-VILLAGRA MR, WIBLE JR. Patterns of evolutionary transformation in the petrosal bone and some basicranial features in marsupial mammals, with special reference to didelphids. J ZOOL SYST EVOL RES 2002. [DOI: 10.1046/j.1439-0469.2002.00173.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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ASHER ROBERTJ. Cranial Anatomy in Tenrecid Insectivorans: Character Evolution Across Competing Phylogenies. AMERICAN MUSEUM NOVITATES 2001. [DOI: 10.1206/0003-0082(2001)352<0001:caitic>2.0.co;2] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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GEISLER JONATHANH. New Morphological Evidence for the Phylogeny of Artiodactyla, Cetacea, and Mesonychidae. AMERICAN MUSEUM NOVITATES 2001. [DOI: 10.1206/0003-0082(2001)344<0001:nmeftp>2.0.co;2] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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WIBLE JOHNR, ROUGIER GUILLERMOW, NOVACEK MICHAELJ, McKENNA MALCOLMC. Earliest Eutherian Ear Region: A Petrosal Referred to Prokennalestes from the Early Cretaceous of Mongolia. AMERICAN MUSEUM NOVITATES 2001. [DOI: 10.1206/0003-0082(2001)322<0001:eeerap>2.0.co;2] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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WIBLE JOHNR, ROUGIER GUILLERMOW. CRANIAL ANATOMY OF KRYPTOBAATAR DASHZEVEGI (MAMMALIA, MULTITUBERCULATA), AND ITS BEARING ON THE EVOLUTION OF MAMMALIAN CHARACTERS. BULLETIN OF THE AMERICAN MUSEUM OF NATURAL HISTORY 2000. [DOI: 10.1206/0003-0090(2000)247<0001:caokdm>2.0.co;2] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Qiu M, Bulfone A, Ghattas I, Meneses JJ, Christensen L, Sharpe PT, Presley R, Pedersen RA, Rubenstein JL. Role of the Dlx homeobox genes in proximodistal patterning of the branchial arches: mutations of Dlx-1, Dlx-2, and Dlx-1 and -2 alter morphogenesis of proximal skeletal and soft tissue structures derived from the first and second arches. Dev Biol 1997; 185:165-84. [PMID: 9187081 DOI: 10.1006/dbio.1997.8556] [Citation(s) in RCA: 385] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The Dlx homeobox gene family is expressed in a complex pattern within the embryonic craniofacial ectoderm and ectomesenchyme. A previous study established that Dlx-2 is essential for development of proximal regions of the murine first and second branchial arches. Here we describe the craniofacial phenotype of mice with mutations in Dlx-1 and Dlx-1 and -2. The skeletal and soft tissue analyses of mice with Dlx-1 and Dlx-1 and -2 mutations provide additional evidence that the Dlx genes regulate proximodistal patterning of the branchial arches. This analysis also elucidates distinct and overlapping roles for Dlx-1 and Dlx-2 in craniofacial development. Furthermore, mice lacking both Dlx-1 and -2 have unique abnormalities, including the absence of maxillary molars. Dlx-1 and -2 are expressed in the proximal and distal first and second arches, yet only the proximal regions are abnormal. The nested expression patterns of Dlx-1, -2, -3, -5, and -6 provide evidence for a model that predicts the region-specific requirements for each gene. Finally, the Dlx-2 and Dlx-1 and -2 mutants have ectopic skull components that resemble bones and cartilages found in phylogenetically more primitive vertebrates.
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Affiliation(s)
- M Qiu
- Center for Neurobiology and Psychiatry, Department of Psychiatry, University of California at San Francisco, 94143-0984, USA
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López-Fuster MJ, Ventura J. Anatomical study of the abdominal arterial system in soricids (Insectivora, Mammalia): functional and phylogenetic implications. Anat Rec (Hoboken) 1997; 248:142-7. [PMID: 9143678 DOI: 10.1002/(sici)1097-0185(199705)248:1<142::aid-ar17>3.0.co;2-p] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
BACKGROUND Information on the anatomy of the abdominal arterial system in Insectivora is scarce. We described the origin, distribution, and variations of the visceral abdominal arteries in some Soricidae in order to provide the first comprehensive data on this subject in Insectivora. Results were interpreted from a functional and phylogenetic viewpoint. METHODS The sample examined consisted of 46 shrews (25 Crocidura russula, 12 Sorex araneus, 5 S. coronatus, 4 S. minutus) captured in the field. Animals were analyzed by injection of coloured latex solution through the left ventricle of the heart and subsequent dissection. RESULTS The coeliacomesenteric trunk was the first visceral branch of the abdominal aorta. The cranial mesenteric artery supplied those parts of the digestive tract attached to the cranial mesentery and usually gave rise to the colic, the caudal pancreaticoduodenal, and the jejunum-ileumcolic arteries. The coeliac artery mainly vascularized the stomach, the liver and the first portion of the duodenum, and the spleen by means of several branches of the left gastric, the "common" hepatic, and the lienal arteries, respectively. The lienal arteries were double. The renal, gonadal, and median sacral arteries were also branches of the abdominal aorta. The caudal mesenteric artery emerged either from the abdominal aorta or from one of the common iliac arteries. CONCLUSIONS Differences in the abdominal blood supply between soricids and more advanced mammals are basically focused on the irrigation of the digestive tract. The presence of double lienal arteries and the absence of right gastric artery and left and right gastroepiploic arteries are related to the primitive type of gut presented in the order and are thought to be the plesiomorphic condition in Eutheria.
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Affiliation(s)
- M J López-Fuster
- Department of Animal Biology, Faculty of Biology, University of Barcelona, Spain
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Reexamination of the morphological evidence for the cohort Epitheria (Mammalia, Eutheria). J MAMM EVOL 1996. [DOI: 10.1007/bf01454253] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Wible JR, Zeller U. Cranial circulation of the pen-tailed tree shrewPtilocercus lowii and relationships of Scandentia. J MAMM EVOL 1994. [DOI: 10.1007/bf01464275] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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