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Segura V, Rasia LL, Candela AM, Flores DA. Postnatal Skull Development Reveals a Conservative Pattern in Living and Fossil Vizcachas Genus Lagostomus (Rodentia, Chinchillidae). J Morphol 2024; 285:e21775. [PMID: 39256990 DOI: 10.1002/jmor.21775] [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: 04/07/2024] [Revised: 08/18/2024] [Accepted: 08/27/2024] [Indexed: 09/12/2024]
Abstract
The plains vizcacha, Lagostomus maximus, is the only living species in the genus, being notably larger than fossil congeneric species, such as Lagostomus incisus, from the Pliocene of Argentina and Uruguay. Here, we compare the skull growth allometric pattern and sexual dimorphism of L. maximus and L. incisus, relating shape and size changes with skull function. We also test whether the ontogenetic trajectories and allometric trends between both sexes of L. maximus follow the same pattern. A common allometric pattern between both species was the elongation of the skull, a product of the lengthening of rostrum, and chondrogenesis on the spheno-occipitalis synchondrosis and coronalis suture. We also detected a low proportion of skull suture fusion. In some variables, older male specimens did not represent a simple linear extension of female trajectory, and all dimorphic traits were related to the development of the masticatory muscles. Sexual dimorphism previously attributed to L. incisus would indicate that this phenomenon was present in the genus since the early Pliocene and suggests social behaviors such as polygyny and male-male competition. Ontogenetic changes in L. incisus were similar to L. maximus, showing a conservative condition of the genus. Only two changes were different in the ontogeny of both species, which appeared earlier in L. incisus compared to L. maximus: the development of the frontal process of the nasals in a square shape, and the straight shape of the occipital bone in lateral view. Juveniles of L. maximus were close to adult L. incisus in the morphospace, suggesting a peramorphic process. The sequence of suture and synchondroses fusion showed minor differences in temporozygomatica and frontonasalis sutures, indicating major mechanical stress in L. maximus related to size. We suggest a generalized growth path in Chinchillidae, but further analyses are necessary at an evolutionary level, including Lagidium and Chinchilla.
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Affiliation(s)
- Valentina Segura
- Unidad Ejecutora Lillo (CONICET-Fundación Miguel Lillo), San Miguel de Tucumán, Argentina
| | - Luciano L Rasia
- CONICET, División Paleontología Vertebrados, Museo de La Plata, La Plata, Argentina
| | - Adriana M Candela
- CONICET, División Paleontología Vertebrados, Museo de La Plata, La Plata, Argentina
| | - David A Flores
- Unidad Ejecutora Lillo (CONICET-Fundación Miguel Lillo), San Miguel de Tucumán, Argentina
- Instituto de Vertebrados, Fundación Miguel Lillo, San Miguel de Tucumán, Argentina
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Fishman R, Kralj-Fišer S, Marglit S, Koren L, Vortman Y. Fathers and sons, mothers and daughters: Sex-specific genetic architecture for fetal testosterone in a wild mammal. Horm Behav 2024; 161:105525. [PMID: 38452612 DOI: 10.1016/j.yhbeh.2024.105525] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Revised: 01/13/2024] [Accepted: 02/29/2024] [Indexed: 03/09/2024]
Abstract
Testosterone plays a critical role in mediating fitness-related traits in many species. Although it is highly responsive to environmental and social conditions, evidence from several species show a heritable component to its individual variation. Despite the known effects that in utero testosterone exposure have on adult fitness, the heritable component of individual testosterone variation in fetuses is mostly unexplored. Furthermore, testosterone has sex-differential effects on fetal development, i.e., a specific level may be beneficial for male fetuses but detrimental for females, producing sexual conflict. Such sexual conflict may be resolved by the evolution of a sex-specific genetic architecture of the trait. Here, we quantified fetal testosterone levels in a wild species, free-ranging nutrias (Myocastor coypus) using hair-testing and estimated testosterone heritability between parent and offspring from the same and opposite sex. We found that in utero accumulated hair testosterone levels were heritable between parents and offspring of the same sex. Moreover, there was a low additive genetic covariance between the sexes, and a low cross-sex genetic correlation, suggesting a potential for sex-specific trait evolution, expressed early on, in utero.
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Affiliation(s)
- Ruth Fishman
- Department of Brain Sciences, Weizmann Institute of Science, Rehovot 76100, Israel(1); The Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 5290002, Israel.
| | - Simona Kralj-Fišer
- Scientific and Research Centre of the Slovenian Academy of Sciences and Arts, Jovan Hadži Institute of Biology, Evolutionary Zoology Laboratory, Ljubljana, Slovenia.
| | - Sivan Marglit
- Hula Research Center, Department of Animal Sciences, Tel-Hai College, Upper Galilee 1220800, Israel
| | - Lee Koren
- The Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 5290002, Israel.
| | - Yoni Vortman
- Hula Research Center, Department of Animal Sciences, Tel-Hai College, Upper Galilee 1220800, Israel; MIGAL-Galilee Research Institute, 11016 Kiryat Shmona, Israel
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Fishman R, Vortman Y, Shanas U, Koren L. Non-model species deliver a non-model result: Nutria female fetuses neighboring males in utero have lower testosterone. Horm Behav 2019; 111:105-109. [PMID: 30790563 DOI: 10.1016/j.yhbeh.2019.02.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Revised: 01/06/2019] [Accepted: 02/14/2019] [Indexed: 12/15/2022]
Abstract
Neighboring fetuses may impact their siblings in various respects, depending on their in utero location and sex. The effects of the intrauterine position (IUP) are widely studied in model organisms, especially laboratory bred murine strains that are characterized by short gestations and altricial offspring. In some species, the proximity to a male fetus and its higher circulating testosterone masculinizes neighboring female fetuses. In utero testosterone exposure might be manifested as higher testosterone concentrations, which contribute to a variation in morphology, reproductive potential and behavior. In this study, we examined the influence of neighboring an opposite sex fetus on testosterone levels in a feral animal model characterized by a long gestation and precocious offspring. Using necropsies of culled nutria (Myocastor coypus), we accurately determined the IUP and quantified testosterone immunoreactivity in fetal hair. We found that as expected, both male and female fetuses neighboring a male in utero had longer anogenital distance. However, females adjacent to males in utero showed lower testosterone levels than male fetuses, while testosterone levels of females without a male neighbor did not differ from those of males. This surprising result suggests an alternative mode by which local exogenous steroids may modify the local fetal environment. Our study emphasizes the importance of examining known phenomena in species with different life histories, other than the traditional murine models, to enhance our understanding of the evolutionary mechanisms that are driving sexual differentiation.
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Affiliation(s)
- Ruth Fishman
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 5290002, Israel
| | - Yoni Vortman
- Hula Research Center, Department of Animal Sciences, Tel-Hai College, Upper Galilee 1220800, Israel
| | - Uri Shanas
- Faculty of Life Sciences, University of Haifa-Oranim, Tivon 3600600, Israel
| | - Lee Koren
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 5290002, Israel.
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Fishman R, Vortman Y, Shanas U, Koren L. Cortisol advantage of neighbouring the opposite sex in utero. ROYAL SOCIETY OPEN SCIENCE 2018; 5:171636. [PMID: 30839724 PMCID: PMC6170571 DOI: 10.1098/rsos.171636] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Accepted: 08/09/2018] [Indexed: 05/14/2023]
Abstract
Population sex ratios naturally fluctuate around equality. It is argued that the production of an equal number of male and female offspring by individual parents should be favoured by selection, if all costs and benefits are equal. Theoretically, an even sex ratio should yield the highest probability for a fetus to be adjacent to a fetus of the opposite sex in utero. This may cause developmental costs or benefits that have been overlooked. We examined the physiological and developmental parameters associated with in utero sex ratios in the nutria (Myocastor coypus), an invasive wildlife species with a strong reproductive output. Using hair testing, we found that litters with even sex ratios had the highest average cortisol levels. Fetuses neighbouring the opposite sex exhibited longer trunks than those neighbouring the same sex, which might imply better lung development. Our results are the first, to our knowledge, to link intra-utero sex ratios and fetal cortisol and suggest that fetal cortisol might be a mechanism by which even sex ratios are maintained via developmental advantages.
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Affiliation(s)
- R. Fishman
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 5290002, Israel
| | - Y. Vortman
- Hula Research Center, Department of Animal Sciences, Tel-Hai College, Upper Galilee 1220800, Israel
| | - U. Shanas
- Faculty of Life Sciences, University of Haifa—Oranim, Tivon 3600600, Israel
| | - L. Koren
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 5290002, Israel
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Female-biased sex ratios are associated with higher maternal testosterone levels in nutria (Myocastor coypus). Behav Ecol Sociobiol 2018. [DOI: 10.1007/s00265-018-2517-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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Nasif NL, Abdala F. Craniodental ontogeny of the pacaranaDinomys branickiiPeters 1873 (Rodentia, Hystricognathi, Caviomorpha, Dinomyidae). J Mammal 2015. [DOI: 10.1093/jmammal/gyv131] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Wysocki MA, Feranec RS, Tseng ZJ, Bjornsson CS. Using a Novel Absolute Ontogenetic Age Determination Technique to Calculate the Timing of Tooth Eruption in the Saber-Toothed Cat, Smilodon fatalis. PLoS One 2015; 10:e0129847. [PMID: 26132165 PMCID: PMC4489498 DOI: 10.1371/journal.pone.0129847] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Accepted: 05/12/2015] [Indexed: 11/19/2022] Open
Abstract
Despite the superb fossil record of the saber-toothed cat, Smilodon fatalis, ontogenetic age determination for this and other ancient species remains a challenge. The present study utilizes a new technique, a combination of data from stable oxygen isotope analyses and micro-computed tomography, to establish the eruption rate for the permanent upper canines in Smilodon fatalis. The results imply an eruption rate of 6.0 millimeters per month, which is similar to a previously published average enamel growth rate of the S. fatalis upper canines (5.8 millimeters per month). Utilizing the upper canine growth rate, the upper canine eruption rate, and a previously published tooth replacement sequence, this study calculates absolute ontogenetic age ranges of tooth development and eruption in S. fatalis. The timing of tooth eruption is compared between S. fatalis and several extant conical-toothed felids, such as the African lion (Panthera leo). Results suggest that the permanent dentition of S. fatalis, except for the upper canines, was fully erupted by 14 to 22 months, and that the upper canines finished erupting at about 34 to 41 months. Based on these developmental age calculations, S. fatalis individuals less than 4 to 7 months of age were not typically preserved at Rancho La Brea. On the whole, S. fatalis appears to have had delayed dental development compared to dental development in similar-sized extant felids. This technique for absolute ontogenetic age determination can be replicated in other ancient species, including non-saber-toothed taxa, as long as the timing of growth initiation and growth rate can be determined for a specific feature, such as a tooth, and that growth period overlaps with the development of the other features under investigation.
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Affiliation(s)
- M. Aleksander Wysocki
- Department of Biological Sciences, Clemson University, Clemson, South Carolina, United States of America
| | - Robert S. Feranec
- Research and Collections Division, New York State Museum, Albany, New York, United States of America
- * E-mail:
| | - Zhijie Jack Tseng
- Division of Paleontology, American Museum of Natural History, New York, New York, United States of America
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