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Sigvardt ZMS, Worsaae K, Savatenalinton S, Kerbl A, Olesen J. Transitions in functional morphology from "large branchiopods" to Cladocera: Video and confocal microscopic studies of Cyclestheria hislopi (Cyclestherida) and Sida crystallina (Cladocera: Ctenopoda). J Morphol 2020; 281:1241-1259. [PMID: 32815589 DOI: 10.1002/jmor.21244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 07/09/2020] [Accepted: 07/17/2020] [Indexed: 11/11/2022]
Abstract
Great diversity is found in morphology and functionality of arthropod appendages, both along the body axis of individual animals and between different life-cycle stages. Despite many branchiopod crustaceans being well known for displaying a relatively simple arrangement of many serially post-maxillary appendages (trunk limbs), this taxon also shows an often unappreciated large variation in appendage morphology. Diplostracan branchiopods exhibit generally a division of labor into locomotory antennae and feeding/filtratory post-maxillary appendages (trunk limbs). We here study the functionality and morphology of the swimming antennae and feeding appendages in clam shrimps and cladocerans and analyze the findings in an evolutionary context (e.g., possible progenetic origin of Cladocera). We focus on Cyclestheria hislopi (Cyclestherida), sister species to Cladocera and exhibiting many "large" branchiopod characters (e.g., many serially similar appendages), and Sida crystallina (Cladocera, Ctenopoda), which likely exhibits plesiomorphic cladoceran traits (e.g., six pairs of serially similar appendages). We combine (semi-)high-speed recordings of behavior with confocal laser scanning microscopy analyses of musculature to infer functionality and homologies of locomotory and filtratory appendages in the two groups. Our morphological study shows that the musculature in all trunk limbs (irrespective of limb size) of both C. hislopi and S. crystallina comprises overall similar muscle groups in largely corresponding arrangements. Some differences between C. hislopi and S. crystallina, such as fewer trunk limbs and antennal segments in the latter, may reflect a progenetic origin of Cladocera. Other differences seem related to the appearance of a specialized type of swimming and feeding in Cladocera, where the anterior locomotory system (antennae) and the posterior feeding system (trunk limbs) have become fully separated functionally from each other. This separation is likely one explanation for the omnipresence of cladocerans, which have conquered both freshwater and marine free water masses and a number of other habitats.
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Affiliation(s)
- Zandra M S Sigvardt
- Natural History Museum of Denmark, University of Copenhagen, Copenhagen, Denmark.,Marine Biological Section, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Katrine Worsaae
- Marine Biological Section, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | | | - Alexandra Kerbl
- Marine Biological Section, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Jørgen Olesen
- Natural History Museum of Denmark, University of Copenhagen, Copenhagen, Denmark
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Shu S, Sigvardt ZMS, Chen X, Olesen J, Rogers DC, Sanoamuang LO. Lynceus amplopedia sp. nov., A New Laevicaudatan Clam Shrimp with Asymmetrically Modified Thoracopods from Yunnan, China (Crustacea: Branchiopoda). Zool Stud 2019; 58:e28. [PMID: 31966329 PMCID: PMC6917564 DOI: 10.6620/zs.2019.58-28] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2019] [Accepted: 07/26/2019] [Indexed: 11/18/2022]
Abstract
Laevicaudata has a nearly global distribution, but only a few records from China. We present a new Lynceus (Crustacea: Branchiopoda: Laevicaudata) species, Lynceus amplopedia sp. nov., from Yunnan, China, which shows significant left-right differences in some non-clasper thoracopods. It can be distinguished from all congeners by asymmetrically modified thoracopods III-VI. In the 'explanate modified' side (usually the left side, occasionally the right) the following modifications are present: endites 4, 5, and endopod enlarged (explanate) (thoracopods III and IV); exopod with 14-15 digitiform processes dorsomedially (thoracopods V and VI); and broad muscular basis (thoracopods III-V). The following modifications are seen in the thoracopods of the opposing 'spinose modified' side (usually the right side, occasionally the left): endite 4 with robust, specialized spines medially (thoracopods V and VI); endite 3 elongate protruding (thoracopod VI), and broad muscular basis (thoracopod V). Other unique characters of the new species include: male and female rostrum sinuate, compound eyes protruding, male claspers with endopod constricted, and endite 3 with two scale patches. We suggest the modified thoracopods may be involved in mating and/or respiration. The diversity of Chinese Lynceus is also discussed.
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Affiliation(s)
- Shusen Shu
- Applied Taxonomic Research Center, Department of Biology,
Faculty of Science, Khon Kaen University, Khon Kaen 40002, Thailand
- Southeast Asia Biodiversity Research Institute, Chinese
Academy of Sciences, Yezin, Nay Pyi Taw 05282, Myanmar
- Kunming Institute of Zoology, 650223, Chinese Academy of
Sciences, Kunming, China
| | - Zandra M. S. Sigvardt
- Natural History Museum of Denmark, University of
Copenhagen, Universitetsparken 15, DK-2100 Copenhagen Ø, Denmark
| | - Xiaoyong Chen
- Southeast Asia Biodiversity Research Institute, Chinese
Academy of Sciences, Yezin, Nay Pyi Taw 05282, Myanmar
- Kunming Institute of Zoology, 650223, Chinese Academy of
Sciences, Kunming, China
| | - Jørgen Olesen
- Natural History Museum of Denmark, University of
Copenhagen, Universitetsparken 15, DK-2100 Copenhagen Ø, Denmark
| | - D. Christopher Rogers
- Kansas Biological Survey and the Natural History Museum
(Biodiversity Institute), Kansas University, Kansas 66047-3759, USA.
| | - La-orsri Sanoamuang
- Applied Taxonomic Research Center, Department of Biology,
Faculty of Science, Khon Kaen University, Khon Kaen 40002, Thailand
- International College, Khon Kaen University, Khon Kaen
40002, Thailand.
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Sigvardt ZMS, Rogers DC, De los Ríos P, Palero F, Olesen J. First molecular phylogeny of Laevicaudata (Crustacea: Branchiopoda) with description of a new species of Lynceus from Chile and an updated key to species in the Americas. INVERTEBR SYST 2019. [DOI: 10.1071/is18073] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The first molecular phylogeny of Lynceus (Crustacea: Branchiopoda: Laevicaudata) is presented together with a description of a new species of laevicaudatan branchiopod from Chile, Lynceus huentelauquensis, sp. nov. DNA sequences were obtained from six species of Lynceus using freshly collected specimens from Europe, North America, South America, and Australia and combined with GenBank sequences from previous studies. Specimens of the new species were collected from a pool on the Huentelauquén Plains near Huentelauquén City. Our molecular analyses placed L. huentelauquensis, sp. nov. within Lynceus and close to a cluster of Australian species, and revealed morphological misidentifications, cross-contamination, or incorrect upload in earlier GenBank sequences. L. huentelauquensis, sp. nov. is separated from other Lynceus primarily by the morphology of the rostrum and the male claspers. L. huentelauquensis, sp. nov. is the first described laevicaudatan from Chile, the sixth from South America, and the 13th from the Americas. The morphology of laevicaudatans from the Americas is reviewed and an updated key to the (male) Lynceidae of the region is provided. Our study highlights the necessity of a revision of Laevicaudata using multiple genetic markers as well as thorough morphological studies on a greater number of taxa.
urn:lsid:zoobank.org:pub:9A783D96-B270-40DF-8361-11BA063C9A0F
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Sigvardt ZMS, Rogers DC, Olesen J. Functional morphology of amplexus (clasping) in spinicaudatan clam shrimps (Crustacea, Branchiopoda) and its evolution in bivalved branchiopods: A video-based analysis. J Morphol 2017; 278:523-546. [DOI: 10.1002/jmor.20649] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Revised: 12/06/2016] [Accepted: 12/10/2016] [Indexed: 11/05/2022]
Affiliation(s)
- Zandra M. S. Sigvardt
- Natural History Museum of Denmark; University of Copenhagen; Universitetsparken 15 DK-2100 Copenhagen Ø Denmark
| | - D. Christopher Rogers
- Kansas Biological Survey and the Natural History Museum (Biodiversity Institute), Kansas University; Higuchi Hall, 2101 Constant Avenue Lawrence KS 66047-3759 USA
| | - Jørgen Olesen
- Natural History Museum of Denmark; University of Copenhagen; Universitetsparken 15 DK-2100 Copenhagen Ø Denmark
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Kaji T, Palmer AR. How reversible is development? Contrast between developmentally plastic gain and loss of segments in barnacle feeding legs. Evolution 2017; 71:756-765. [PMID: 28012177 DOI: 10.1111/evo.13152] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Accepted: 11/17/2016] [Indexed: 01/14/2023]
Abstract
Segmented organisms and structures have fascinated biologists since William Bateson first described homeotic transformation and recognized the fundamental evolutionary significance of segmental organization. On evolutionary time scales, segments may be lost or gained during major morphological transitions. But how segment loss compares to gain on developmental time scales remains mysterious. Here, we examine the ease of reverse development (opposite to normal growth) by comparing developmentally plastic leg segment loss versus gain in individual barnacles transplanted between different water flow conditions. Plastic segment addition occurred rapidly (one to two molts) and exclusively near the limb base. In contrast, developmentally plastic segment loss-the first observation in any arthropod-took much longer (>10 molts) and, remarkably, occurred throughout the leg (23% of losses occurred mid-limb). Segment loss was not a simple reversal of segment addition. Intersegmental membranes fused first, followed by elimination of duplicate tendons and gradual shortening (but not loss) of duplicate setae. Setal loss, in particular, may impose a severe developmental constraint on arthropod segment fusion. This asymmetric developmental potential (time lag of phenotypic response)-plastic segment addition (amplified normal development) is faster and more orderly than segment loss (reverse development)-adds a new dimension to models of developmental plasticity because the cost of making a developmental mistake in one direction will be greater than in the other.
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Affiliation(s)
- Tomonari Kaji
- Systematics and Evolution Group, Department of Biological Sciences, University of Alberta, Edmonton, Alberta, T6G 2E9, Canada.,Bamfield Marine Sciences Centre, Bamfield, British Columbia, V0R 1B0, Canada
| | - A Richard Palmer
- Systematics and Evolution Group, Department of Biological Sciences, University of Alberta, Edmonton, Alberta, T6G 2E9, Canada.,Bamfield Marine Sciences Centre, Bamfield, British Columbia, V0R 1B0, Canada
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