Cryptic species,taxonomic inflation,or a bit of both? New species phenomenon in Sri Lanka as suggested by a phylogeny of dwarf geckos (Reptilia,Squamata, Gekkonidae,Cnemaspis)

We evaluated the status of 16 of 22 recognized Sri Lankan Cnemaspis Strauch species, and flagged overlooked diversity with two mitochondrial (cyt b & ND2) and two nuclear markers (RAG1 & PDC) totalling 2829 base pairs. A fossil-calibrated timetree and sampling of other South Asian Cnemaspis provide insights into the diversification of the genus in peninsular India and Sri Lanka. Phylogenetic analyses consistently inferred two broad clades within South Asian Cnemaspis, with Sri Lankan species in two clades, which we call the podihuna and kandiana clades. Each Sri Lankan clade as a whole is sister to Indian taxa and nested within Indian lineages. Cnemaspis modigliani Das from Indonesia is a member of the kandiana clade. This suggests a minimum of two dispersal events between India and Sri Lanka and one between Sri Lanka/India and South-east Asia. South Asian Cnemaspis date back to at least the Eocene, in Sri Lanka to the early Miocene, with late Miocene diversification in the kandiana clade. All but one of the named species we sampled is likely to be valid, and 10 divergent unnamed lineages may warrant specific recognition. A resolution of Sri Lankan Cnemaspis taxonomy will require thorough sampling and the use of both morphological and molecular data.     

Evidence and hypothesis in biogeography

Evidence can provide support for or against a particular biogeographical hypothesis. Treating a hypothesis as if it were evidence or an empirical observation confounds many biogeographical analyses. We focus on two recent publications that address, in part, the evolution of the biota of Sulawesi, the large Indonesian island in the centre of the Indo‐Australian Archipelago. Many biogeographical explanations are hampered by invoking simple notions of mechanism or process – dispersal and vicariance – or constraints, such as dispersal from a centre of origin, and, in so doing, dismiss more complex geological phenomena such as emergent volcanoes within island chains or composite areas as irrelevant. Moreover, they do not search for, therefore never discover, biogeographical patterns that may better explain the distribution of biota through time.     

Oceanic transport of calcified eggs: taphonomic and biogeographic implications

Estimates of the temporal and spatial resolution of fossil egg assemblages are required to constrain the inferences that can logically be drawn during assemblage analysis. Consequently, understanding egg transport mechanisms is required before conclusions are developed. Bird eggs are buoyant during part of development and can float from near shore nests during high tides, storm surges, or flooding. Complete and unbroken eggs have survived transoceanic transport. Evidence of these transport processes operating in the past is suggested by the recovery of fossil eggshell in marine deposits. Transport of eggs can potentially confound fossil assemblage spatial analysis since evidence of oceanic transport may not be present on an eggshell when collected. Bird embryos exposed to cold temperatures and immersed in both fresh and salt water can survive from hours to two days, suggesting that oceanic transport of viable eggs is possible, a conclusion further supported by field observations. Eggs of other taxa show similar environmental survival trends and may also be capable of surviving oceanic transport through floatation or rafting. In addition, if viable eggs are transported across seas and hatch, emigration or gene flow of terrestrial egg-laying vertebrates may be possible between landmasses.     

A new blunt-snouted dyrosaurid,Anthracosuchus balrogus gen. et sp. nov. (Crocodylomorpha,Mesoeucrocodylia), from the Palaeocene of Colombia

A new exceptionally brevirostrine dyrosaurid is described from the middle Palaeocene (58–60 million years ago) Cerrejón Formation, northeastern Colombia, based on four partial skulls and associated postcrania. This taxon is unique among dyrosaurids not only in skull shape, but also in having orbital tuberosities, and osteoderms that are dorsoventrally thick and unpitted, a trait otherwise unknown in Crocodylomorpha. Results from a cladistic analysis of Dyrosauridae suggest that the new taxon, together with Cretaceous–Palaeocene Chenanisuchus lateroculi from Africa and Cerrejonisuchus improcerus also from the Cerrejón Formation, are the most basal members of the family. Results from a biogeographic analysis indicate at least three independent dispersals of dyrosaurids from Africa to the New World occurred in the Late Cretaceous or early Palaeocene. Widely set orbits in the new taxon indicate a deviation from surface-based predation, characteristic of other dyrosaurids, to sub-surface predation, as in modern Gavialis. Tooth impressions found on turtle shells recovered from the same locality match well with teeth of the new taxon indicating possible predation.http://www.zoobank.org/urn:lsid:zoobank.org:pub:AB2B24A5-27CC-4D3F-B580-F11F17851CE6     

溪蛉科研究进展

溪蛉是脉翅目中比较稀少的一个类群,可以作为天敌资源和研究昆虫演化的"活化石"材料,但历史上溪蛉科在脉翅目中的系统地位一直是个颇具争议难以解决的问题。本文综述了溪蛉科国内外分类研究简史,探讨了溪蛉科的地理分布,以及溪蛉科生物学、化石等其他方面的研究进展。最后提出了溪蛉科分类研究中亟须解决的几个问题并呼吁应该加强对其应用价值的研究。     

The biology of the Northeastern Pacific Turridae. V. Demersal development,synchronous settlement and other aspects of the larval biology of Oenopota levidensis

Summary

The larval development and metamorphosis of a turrid gastropod is described for the first time. This snail, Oenopota levidensis, is typical of the boreal genus Oenopota, which has over 150 described species. Development to a veliger occurs within a lenticular capsule in about 50 days. The capsules hatch to release veligers which swim for less than a week. The remainder of their planktotrophic larval period is spent demersally. Demersal veligers assumed one of two characteristic postures; they remain on the bottom with the velum either extended laterally or folded over the shell. These demersal veligers continue development and metamorphose after another 25 days. The majority of the veligers in the 55 cultures examined metamorphosed and settled within a 96-h period, even though their oviposition occurred over a 47-day period. Potential selective forces leading to this synchronous settlement are proposed.