摘要:

A numerical cladistic analysis, based on 23 terminal groups and 63 morphological characters, was done to infer phylogenetic relationships within the Eurasian catfish family Siluridae. Nine hundred and forty‐five equally most parsimonious trees (134 steps, consistency index 0.634) were found that differ in their resolutions of four polychotomies. Strict consensus of these trees includes ten internal nodes, does not support monophyly ofSilurus, OmpokandKryptopterus, as usually defined, and offers ambiguous support for monophyly ofWallago. SilurusandKryptopterusare each composed of two non‐sister group clades, andOmpokis composed of at least two such clades. Heuristic searches constrained by monophyly ofSilurus, OmpokorKryptopterusyielded trees five or six steps longer than the shortest trees free of constraints. The strict consensus also infers a basal dichotomy that separates the Siluridae into a temperate Eurasian clade with about 20 nominal species and a subtropical/tropical south and southeast Asian clade with about 75 nominal species. The distributions of these clades overlap in a relatively narrow region of east Asia. A heuristic search for trees 1 step longer than the shortest trees yielded 253890 trees. A strict consensus of these trees also infers a basal dichotomy between the above‐mentioned clades. This analysis revealed four additional putative synapomorphies of the Siluridae, pending further resolution of the family's outgroup relation

ISSN:0024-4082    

DOI:10.1111/j.1096-3642.1995.tb02322.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

Based on the internal anatomy of petrosal bones as shown in radiographs and scanning electron microscopy, the inner ear structures of Late Cretaceous marsupials and placentals (about 65 Myr ago) from the Bug Creek Anthills locality of Montana, USA, are described. The inner ears of Late Cretaceous marsupials and placentals are similar to each other in having the following tribosphenic therian synapomorphies: a fully coiled cochlea, primary and secondary osseous spiral laminae, the perilymphatic recess merging with the scala tympani of the cochlea, an aqueductus cochleae, a true fenestra cochleae, a radial pattern of the cochlear nerve and an elongate basilar membrane extending to the region between the fenestra vestibuli and fenestra cochleae. The inner ear structures of living therians differ from those of their Late Cretaceous relatives mainly in having a greater number of spiral turns of the cochlea and a longer basilar membrane. Functionally, a coiled cochlea not only permits the development of an elongate basilar membrane within a restricted space in the skull but also allows a centralized nerve system to innervate the elongate basilar membrane. Qualitative and quantitative analyses show that, with a typical therian inner ear, Late Cretaceous marsupials and placentals were probably capable of high‐frequency hearin

ISSN:0024-4082    

DOI:10.1111/j.1096-3642.1995.tb02323.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

A comparative study of the external chorion morphology of West‐Palaearctic satyrine butterflies is attempted, based on descriptions of 38 species and a survey of previously published data. The correlations between selected characters, the results of phylogenetic analysis based on egg characters, and their congruence with the current taxonomy of these butterflies, are tested, in order to estimate the potential use of egg characters in systematic studies. A relatively high number of characters may be derived from the outer chorion morphology, although decisions on homology may require detailed knowledge of the fine structure of chorion. There is evidence for correlation between some quantitative traits, like egg size and number of micropyles, which might in turn depend on adult size. Egg morphology can sometimes be interpreted in terms of ecological adaptations, and hence provides information that should be used in systematics. Evidence from satyrine butterflies suggests that the external chorionic features are highly homoplasious, and probably more useful at low than at high taxonomic levels within Satyrina

ISSN:0024-4082    

DOI:10.1111/j.1096-3642.1995.tb02324.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

ISSN:0024-4082    

DOI:10.1111/j.1096-3642.1995.tb02322a.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY