The Structure of Molar Surfaces of the Mandibles of Sidoidea (Crustacea: Daphniiformes). 1. <i>Holopediurn gibberum</i> Z<scp>ADDACH</scp>, 1848

Glagolev, S. M.; Korovchinsky, N. M.

doi:10.1002/iroh.19920770212

Cited by 2 publications

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“…Mandible gnathal edge: (0) with incisor and molar process; (1) ellipsoid molar process, with pores; (2) with separate teeth Two different kinds of mandibular gnathal edges exist in branchiopods (Linder, 1945;Richter, 2004). Representatives of Anostraca (Mura, 1995(Mura, , 1996, Spinicaudata, Cyclestherida (Richter, 2004) and certain Cladocera (Edwards, 1980;Glagolev and Korovchinsky, 1992;Kotov, 1998Kotov, , 2000a) have a molar process that covers the entire gnathal edge (scored 1). In these taxa, the pars molaris consists of several rows of comb-like projections originating from the primary surface of the gnathal edge.…”

Section: Two Segmentsmentioning

confidence: 98%

Phylogeny of Branchiopoda (Crustacea) based on a combined analysis of morphological data and six molecular loci

2007

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The phylogenetic relationships of branchiopod crustaceans have been in the focus of a number of recent morphological and molecular systematic studies. Although agreeing in some respects, major differences remain. We analyzed molecular sequences and morphological characters for 43 branchiopods and two outgroups. The branchiopod terminals comprise all eight ''orders''. The molecular data include six loci: two nuclear ribosomal genes (18S rRNA, 28S rRNA), two mitochondrial ribosomal genes (12S rRNA, 16S rRNA), one nuclear protein coding gene (elongation factor 1a), and one mitochondrial protein coding gene (cytochrome c oxidase subunit I). A total of 65 morphological characters were analyzed dealing with different aspects of branchiopod morphology, including internal anatomy and larval characters. The morphological analysis resulted in a monophyletic Phyllopoda, with Notostraca as the sister group to the remaining taxa supporting the Diplostraca concept (''Conchostraca'' + Cladocera). ''Conchostraca'' is not supported but Cyclestheria hislopi is the sister group to Cladocera (constituting together Cladoceromorpha) and Spinicaudata is closer to Cladoceromorpha than to Laevicaudata. Cladocera is supported as monophyletic. The combined analysis under equal weighting gave results in some respects similar to the morphological analysis. Within Phyllopoda, Cladocera, Cladoceromorpha and Spinicaudata + Cladoceromorpha are monophyletic. The combined analysis is different from the morphological analysis with respect to the position of Notostraca and Laevicaudata. Here, Laevicaudata is the sister group to the remaining Phyllopoda and Notostraca is sister group to Spinicaudata and Cladoceromorpha. A sensitivity analysis using 20 different parameter sets (different insertion-deletion [indel] ⁄ substitution and transversion ⁄ transition ratios) show the monophyly of Anostraca, Notostraca, Laevicaudata, Spinicaudata, Cladoceromorpha, Cladocera, and within Cladocera, of Onychopoda and Gymnomera under all or almost all (i.e., 19 of 20) parameter sets. Analyses with an indel-to-transversion ratio up to 2 result in monophyletic Phyllopoda, with Laevicaudata as sister group to the remaining Phyllopoda and with Spinicaudata and Cladoceromorpha as sister groups. Almost all analyses (including those with higher indel weights) result in the same topology when only ingroup taxa are considered.Ó The Willi Hennig Society 2007.Branchiopoda comprise approximately 1180 described species of mainly freshwater dwelling crustaceans (Adamowicz and Purvis, 2005). It includes taxa with a general, archaic morphology very similar to that of some Cambrian and Devonian crustacean fossils (Anostraca, Notostraca, Spinicaudata), as well as taxa that are highly specialized for predatory, scraping, parasitism, and advanced filtration such as the water fleas (Scourfield

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Section: Two Segmentsmentioning

confidence: 98%

Phylogeny of Branchiopoda (Crustacea) based on a combined analysis of morphological data and six molecular loci

2007

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A comparison of the mandibular gnathal edges in branchiopod crustaceans: implications for the phylogenetic position of the Laevicaudata

Richter

2003

Zoomorphology

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Two significantly different types of mandibular gnathal edges present in extant Branchiopoda are documented by using SEM. The Anostraca, Spinicaudata, Cyclestherida, and certain Cladocera have a pars molaris that forms the entire gnathal edge. In these taxa, the pars molaris consists of comb-like projections originating from the primary surface of the gnathal edge. The 'comb teeth' form the grinding surface at a second, more distal level. The central area of the molar surface is formed as a smooth plate, perforated by numerous small pores. These corresponding features are interpreted as homologous and indicate the homology of this type of gnathal edge. In comparison with the mandibular gnathal edges of other mandibulate taxa, the ellipsoid pars molaris forming the entire gnathal edge can be interpreted as an apomorphy of the Branchiopoda. Another type of gnathal edge is found in the Notostraca and Laevicaudata. It is characterized by several parallel-oriented teeth. Each of these teeth possesses a dorsal and a ventral cusp, both connected by a concave ridge. In addition, a smaller tooth-like structure, but showing more differences to the other teeth, is present anteriorly, and an incisor or canine-like tooth posteriorly. These similarities between laevicaudatan and notostracan gnathal edges are detailed enough to accept primary homology also of the second type of gnathal edge. Differences between the gnathal edges concern the distinct asymmetry of the mandibles in Notostraca and their symmetry in Laevicaudata. In comparison with the other type of gnathal edge, this type has to be interpreted as a synapomorphy of Notostraca and Laevicaudata. This is in conflict with other characters supporting a monophyletic Diplostraca, with the Laevicaudata as sister group to Spinicaudata + Cladoceromorpha.

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The Structure of Molar Surfaces of the Mandibles of Sidoidea (Crustacea: Daphniiformes). 1. Holopediurn gibberum ZADDACH, 1848

Abstract: The morphology of mandibles of Holopedium gibberum was studied using scanning electron microscopy. They are strongly asymmetric and differ with that of Anemia and Podonidae and similar with that of Branchinecta and Daphniiformes especially Penilia.

Cited by 2 publications

References 7 publications

Phylogeny of Branchiopoda (Crustacea) based on a combined analysis of morphological data and six molecular loci

Phylogeny of Branchiopoda (Crustacea) based on a combined analysis of morphological data and six molecular loci

A comparison of the mandibular gnathal edges in branchiopod crustaceans: implications for the phylogenetic position of the Laevicaudata

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