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Putative Synapomorphies (putative + synapomorphy)
Selected Abstracts1 Taxon sampling and inferences about diatom phylogenyJOURNAL OF PHYCOLOGY, Issue 2003A. J. Alverson Proper taxon sampling is one of the greatest challenges to understanding phylogenetic relationships, perhaps as important as choice of optimality criterion or data type. This has been demonstrated in diatoms where centric diatoms may either be strongly supported as monophyletic or paraphyletic when analyzing SSU rDNA sequences using the same optimality criterion. The effect of ingroup and outgroup taxon sampling on relationships of diatoms is explored for diatoms as a whole and for the order Thalassiosirales. In the latter case, SSU rDNA and rbcL sequence data result in phylogenetic relationships that appear to be strongly incongruent with morphology and broadly incongruent with the fossil record. For example, Cyclotella stelligera Cleve & Grunow behaves like a rogue taxon, jumping from place to place throughout the tree. Morphological data place C. stelligera near the base of the freshwater group as sister to the extinct genus Mesodictyon Theriot and Bradbury, suggesting that it is an old, long branch that might be expected to "misbehave" in poorly sampled trees. Cyclotella stelligera and C. bodanica Grunow delimit the diameter of morphological diversity in Cyclotella, so increased sampling of intermediate taxa will be critical to resolving this part of the tree. Morphology is sampled for a much greater number of taxa and many transitional states of putative synapomorphies seem to suggest a robust morphological hypothesis. The Thalassiosirales are unstable with regards to taxon sampling in the genetic data, suggesting that perhaps the morphological hypothesis is (for now) preferable. [source] Phylogeny of the Eucoilinae (Hymenoptera: Cynipoidea: Figitidae)CLADISTICS, Issue 2 2002F.M. Fontal-Cazalla The Eucoilinae are a diverse and important group of parasitoids of Diptera, particularly in the tropics, but they are poorly known systematically and their generic classification is partly chaotic. Here, we present the first comprehensive cladistic analysis of higher eucoiline relationships. The analysis is based on 148 skeletal characters of adults documented in more than 1100 digital images available in an Internet-accessible database. The characters were coded for 45 taxa representing 35 eucoiline genera, spanning the entire diversity of the group, and 7 outgroup genera. Relationships were partly difficult to resolve and parsimony analysis under implied weights performed considerably better than analysis under uniform weights. The results support the monophyly of the Eucoilinae and show that eucoilines are most closely related to the figitid subfamilies Emargininae and Pycnostigminae, but are ambiguous concerning the exact relationships among these three lineages. Of the 6 eucoiline genus groups recognized by Nordlander in 1982 (Entomol. Scand. 13, 269,292), only 2 are supported as monophyletic: the Trybliographa and Kleidotoma groups. The Gronotoma group is a paraphyletic assemblage of two different basal clades of eucoilines. The Rhoptromeris group is unnatural and only the 2 core genera, Rhoptromeris and Trichoplasta, form a monophyletic lineage. The data are ambiguous concerning the Ganaspis group, which appears to be paraphyletic, and the Chrestosema group, which may be a good clade. Based on the results we propose a modified system of informal genus groups in the Eucoilinae and discuss putative synapomorphies supporting each genus group. The proposed relationships imply that the first eucoilines were parasitoids of leaf-mining agromyzids. The earliest split in the group was apparently between an Afrotropical and a Neotropical lineage, and much of the early radiation of the group occurred in these regions, particularly in the Neotropics. [source] Ontogeny and homology of the claustra in Otophysan Ostariophysi (Teleostei)JOURNAL OF MORPHOLOGY, Issue 8 2006Ralf Britz Abstract We studied the ontogeny of the claustrum comparatively in representatives of all otophysan subgroups. The claustrum of cypriniforms has a cartilaginous precursor, the claustral cartilage, which subsequently ossifies perichondrally at its anterior face and develops an extensive lamina of membrane bone. The membrane bone component of the claustrum and its close association with the atrium sinus imparis, a perilymphatic space of the Weberian apparatus, are both synapomorphies of cypriniforms. The characiform claustrum is not preformed in cartilage and originates as a membrane bone ossification, a putative synapomorphy of that taxon. Among siluriforms, the claustrum is present only in more basal groups and originates as an elongate cartilage that ossifies in a characteristic ventrodorsal direction, possibly a synapomorphy of catfishes. Gymnotiforms lack the claustral cartilage and claustrum. We review all previous hypothesis of claustrum homology in light of the above findings and conclude that the most plausible hypothesis is the one originally proposed by Bloch ([1900] Jen Z Naturw 34:1,64) that claustra are homologs of the supradorsals of the first vertebra. J. Morphol. © 2006 Wiley-Liss, Inc. [source] New results concerning the morphology of the most ancient dragonflies (Insecta: Odonatoptera) from the Namurian of Hagen-Vorhalle (Germany)JOURNAL OF ZOOLOGICAL SYSTEMATICS AND EVOLUTIONARY RESEARCH, Issue 4 2001G. Bechly The holotype specimen of the ,protodonate'Erasipteroides valentini (Brauckmann in Brauckmann et al., 1985) and the paratype specimen K-13 of the giant ,protodonate'Namurotypus sippeliBrauckmann and Zessin, 1989 from the Upper Carboniferous (Namurian B) of Hagen-Vorhalle (Germany) are redescribed, and a new specimen of Erasipteroides cf. valentini is described. The new evidence is used to refine the groundplan reconstruction of Odonatoptera and the reconstruction of odonatoid phylogeny. Prothoracic winglets for Erasipteroides and the absence of an archaedictyon are documented. Furthermore, a very long and sclerotized ovipositor with gonangulum is described from the female holotype specimen of Erasipteroides valentini, and it is proposed that it was not used for endophytic but for endosubstratic oviposition. The record of prothoracic winglets in early odonatoids, and their presence in fossil Palaeodictyoptera and ,protorthopteres', indicates that the groundplan of Pterygota indeed included three pairs of wings. A phylogenetic analysis suggests that the Palaeozoic giant Meganisoptera and "higher" odonatoids (incl. crowngroup Odonata) together form a monophyletic group which is here named Euodonatoptera. Erasipteroides and the other ,Erasipteridae' are shown to be more closely related to Euodonatoptera than to Eugeropteridae. The description of the male primary genital structures of Namurotypus sippeli is emended and a new interpretation is proposed, including new hypotheses concerning their function. The males of Namurotypus had a paired penis with a pair of lateral parameres, and a pair of leaf-like, but still segmented, gonopods. Segmented leg-like male gonopods are considered as a groundplan character of insects, while a paired penis is regarded as a putative synapomorphy of the palaeopterous insect orders Palaeodictyopteroida, Ephemeroptera, and Odonatoptera. It is proposed that Namurotypus did not mate by direct copulation but retained the archaic deposition of external spermatophores, just like the primarily wingless insects. The sigmoidal male cerci may have been placed behind the female head and used to drag the female over the spermatophore, which is remotely similar to the mating behaviour of some extant arachnids (e.g. Amblypygi). Three hypothetical scenarios regarding the evolution of secondary copulation in modern Odonata are proposed. Neue Erkenntnisse zur Morphologie der ältesten Libellen (Insecta: Odonatoptera) aus dem Namurium von Hagen-Vorhalle (Deutschland) Das Holotypusexemplar der ,Protodonate'Erasipteroides valentini (Brauckmann in Brauckmann et al., Geol. Paläont. Westfalen 3, 1,131, 1985) und das Paratypusexemplar K-13 der riesenwüchsigen ,Protodonate'Namurotypus sippeliBrauckmann and Zessin, 1989 aus dem Oberkarbon (Namurium B) von Hagen-Vorhalle (Deutschland) werden wiederbeschrieben. Die neuen Erkenntnisse werden zu einer Präzisierung der Grundplanrekonstruktion der Odonatoptera und für die Rekonstruktion der Libellenstammesgeschichte verwendet. Für Erasipteroides werden prothorakale Flügelchen beschrieben und das Fehlen eines Archaedictyons wird belegt. Des weiteren wird ein sehr langer und sklerotisierter Ovipositor mit Gonangulum für das weibliche Holotypusexemplar von Erasipteroides valentini beschrieben, und es wird vorgeschlagen, dass dieser nicht zur endophytischen Eiablage, sondern zur endosubstratischen Eiablage diente. Der Nachweis prothorakaler Flügelchen bei frühen Libellen sowie deren Vorkommen bei fossilen Palaeodictyoptera und ,Protorthopteren', deutet darauf hin, dass zum Grundplan der Pterygota drei Flügelpaare gehörten. Eine phylogenetische Analyse legt nahe, dass die riesenwüchsigen Meganisoptera des Paläozoikums und die ,höheren' Odonaten (inkl. Kronengruppe Odonata) gemeinsam eine monophyletische Gruppe bilden, die hier als Euodonatoptera benannt wird. Es wird gezeigt, dass Erasipteroides und die übrigen ,Erasipteridae' näher mit den Euodonatoptera verwandt sind als die Eugeropteridae. Die Beschreibung der primären männlichen Geschlechtsorgane von Namurotypus sippeli wird ergänzt, und eine neue Interpretation sowie neue Hypothesen zu deren Funktion werden vorgestellt. Die Männchen von Namurotypus besaßen einen paarigen Penis mit einem Paar lateraler Parameren und einem Paar blattartiger, aber noch segmentierter Gonopoden. Segmentierte, beinartige, männliche Gonopoden werden als Grundplanmerkmale der Insekten angesehen, während ein paariger Penis als potentielle Synapomorphie der paläopteren Insektenordnungen Palaeodictyopteroida, Ephemeroptera und Odonatoptera betrachtet wird. Es wird vorgeschlagen, dass die Paarung bei Namurotypus nicht durch eine direkte Kopulation ablief, sondern durch das Absetzen freier Spermatophoren, so wie bei den primär flügellosen Insekten. Die sigmoidalen männlichen Cerci könnten hinter dem weiblichen Kopf platziert worden sein, um das Weibchen über die Spermatophore zu dirigieren, ähnlich dem Paarungsverhalten mancher rezenter Spinnentiere (z.B. Amblypygi). Drei hypothetische Szenarien zur Evolution der sekundären Kopulation bei modernen Libellen werden vorgestellt. [source] | ||||||||||