Did Komodo dragons evolve to eat pygmy elephants?

Nature 326: 832.

All the large mammal species on which Komodo Dragons now prey were introduced to Flores by humans after BC 3000. What did they eat before then? During the Pleistocene, Flores supported two species of now-extinct elephants, the small Stegodon trigonocephalus florensis and the pygmy S. sompoensis (also called S. timoriensis). Hence Auffenberg's suggestion' that the Dragons evolved as a specialized predator on pygmy elephants, formerly the sole large prey available on Flores.

diamond-biblio

Limitations of Climatic Data for Inferring Species Boundaries: Insights from Speckled Rattlesnakes.

PLoS ONE 10(6): e0131435. doi:10.1371/journal.pone.013143

Abstract:

Phenotypes, DNA, and measures of ecological differences are widely used in species delimitation. Although rarely defined in such studies, ecological divergence is almost always approximated using multivariate climatic data associated with sets of specimens (i.e., the “climatic niche”); the justification for this approach is that species-specific climatic envelopes act as surrogates for physiological tolerances. Using identical statistical procedures, we evaluated the usefulness and validity of the climate-as-proxy assumption by comparing performance of genetic (nDNA SNPs and mitochondrial DNA), phenotypic, and climatic data for objective species delimitation in the speckled rattlesnake (Crotalus mitchellii) complex. Ordination and clustering patterns were largely congruent among intrinsic (heritable) traits (nDNA, mtDNA, phenotype), and discordance is explained by biological processes(e.g., ontogeny, hybridization). In contrast, climatic data did not produce biologically meaningful clusters that were congruent with any intrinsic dataset, but rather corresponded to regional differences in atmospheric circulation and climate, indicating an absence of inherent taxonomic signal in these data. Surrogating climate for physiological tolerances adds artificial weight to evidence of species boundaries, as these data are irrelevant for that purpose. Based on the evidence from congruent clustering of intrinsic datasets, we recommend that three subspecies of C.mitchellii be recognized as species: C.angelensis,C.mitchellii, and C.Pyrrhus.

meik-biblio

Evolution of rattlesnakes (Viperidae; Crotalus) in the warm deserts of western North America shaped by Neogene vicariance and Quaternary climate change.

Molecular Ecology (2006) 15, 3353 – 3374. doi: 10.1111/j.1365-294X.2006.03007.x

Abstract:

During Pleistocene, the Laurentide ice sheet rearranged and diversified biotic distributionsin  eastern  North  America,  yet  had  minimal  physical  impact  in  western  North  Americawhere  lineage  diversification  is  instead  hypothesized  to  result  from  climatic  changes.  If Pleistocene climatic fluctuations impacted desert species, the latter would reflect patterns of restricted gene flow concomitant with indications of demographic bottlenecks. Accordingly, molecular evidence for refugia should be present within these distributions and for subsequent range expansions as conditions improved. We sought answers to these questions by evaluating mitochondrial DNA (mtDNA) sequences from four species of rattle-snakes [Crotalus mitchellii (speckled rattlesnake), Crotalus cerastes (sidewinder), Crotalus tigris (tiger rattlesnake), Crotalus ruber (red  diamond  rattlesnake)] with distributions restricted to desert regions of southwestern North  America. We inferred relationships using  parsimony  and  maximum likelihood, tested  intraspecific  clades  for  population expansions, applied an isolation-with-migration model to determine bi-directional migration rates (m) among  regions, and inferred divergence times for species and clades by applying a semiparametric penalized likelihood approach to our molecular data. Evidence for significant range expansion was present in two of eight  regions in  two  species (Crotalus mitchellii pyrrhus, C. tigris region north). Two species (C. cerastes, C. mitchellii) showed a distribution concomitant with northward displacement of Baja California from mainland México, followed by vicariant separation into subclades. Effects of Pleistoceneclimate  fluctuations were found in the distributions of all four species. Three regional diversification patterns were  identified: (i) shallow genetic diversity that resulted  from Pleistocene climatic events (C. tigris, C. ruber); (ii)  deep Pleistocene divisions indicating allopatric segregation of subclades within refugia (C. mitchellii, C. cerastes); and (iii) line-age diversifications that extended to Pliocene or Late Miocene (C. mitchellii, C. cerastes). Clade-diversifying and clade-constraining effects impacted the four species of rattlesnakes unequally.  We found relatively high levels of molecular  diversification in the two most broadly distributed species (C. mitchellii, C. cerastes), and lower levels of genetic diversification in the two species (C. tigris, C. ruber) whose ranges are relatively more restricted. Furthermore, in several cases, the distributions of subspecies were not congruent with our molecular information. We suggest  regional conservation perspectives for southwestern deserts cannot rely upon subspecies as biodiversity surrogates, but must instead employ a molecular and deep historical perspective as a primary mechanism to frame biodiversity reserves within this region.

douglas-biblio

A preliminary analysis of phylogenetic relationships and biogeography of the dangerously venomous Carpet Vipers, Echis (Squamata, Serpentes, Viperidae) based on mitochondrial DNA sequences.

Amphibia-Reptilia 30(2):273-282. DOI: 10.1163/156853809788201090.

Abstract:

Phylogenetic analysis of 1117 bp of mitochondrial DNA sequences (731 bp of cytochrome b and 386 bp of 16S rRNA) indicate that Echis consists of four main clades: E. ocellatus, and the E. coloratus, E. pyramidum, and E. carinatus groups. In the E. coloratus group, E. coloratus itself shows substantial genetic divergence from E. omanensis, corroborating their separate species status. In the E. pyramidum clade, E. pyramidum from Egypt and E. leucogaster from West Africa are genetically very similar, even though samples are separated by 4000 km. South Arabian populations of the E. pyramidum group are much better differentiated from these and two species may be present, animals from Dhofar, southern Oman probably being referable to E. khosatzkii. In the E. carinatus group, specimens of E. carinatus sochureki and E. multisquamatus are very similar in their DNA. The phylogeny indicates that the split between the main groups of Echis was followed by separation of African and Arabian members of the E. pyramidum group, and of E. coloratus and E. omanensis. The last disjunction probably took place at the lowlands that run southwest of the North Oman mountains, which are likely to have been intermittently covered by marine incursions; they also separate the E. pyramidum and E. carinatus groups and several sister taxa of other reptiles. The E. carinatus group may have spread quite recently from North Oman into its very extensive southwest Asian range, and there appears to have been similar expansion of E. pyramidum (including E. leucogaster) in North Africa. Both these events are likely to be associated with the marked climatic changes of the Pleistocene or late Pliocene. Similar dramatic expansions have also recently occurred in three snake species in Iberia.

arnold-biblio

Constraints, Allometry, and Adaptation: Food Habits and Reproductive Biology of Australian Brownsnakes (Pseudonaja: Elapidae).

Herpetologica. 45 (2): 195–207.

shine-biblio

De Arabische Cobra (Naja arabica) Scortecchi 1932 in gevangenschap.

Litteratura Serpentium 34 (2): 200-215.

Introduction:

The Arabian cobra (Naja arabica) is a species that has not been noted in zoological collections or in private collections outside the countries of its natural occurrence. This species was thought to be a subspecies of the Egyptian cobra (Naja haje), but was raised at the specific rank by Trape et al. (2009). The species is categorised by IUCN as Least Concern but threats due to intense collecting for venom extraction and local animal trade markets may have serious longterm effects on wild populations (Cox, Mallon, Bowles, Els, Tognelli, 2012) Much is unknown about the species and its captive husbandry requirements. Due to a recent collaboration between the authors of two institutions a more in-depth understanding of the species captive management can be concluded to ensure their sustainable management in captive collections.

els-biblio

A Contribution to the Herpetology of West Pakistan.

Bulletin of the American Museum of Natural History 134 (Article 2): 27-184.

Inhalt:

The present paper is a report on a collection of approximately 1500 amphibians and reptiles from West Pakistan and an account of natural historyo bservations made on the herpetofauna during a period of aboutfour years.A definitive herpetology of the province must await more complete zoologicale xploration and the examination of larger and more representative collections.

minton-biblio

Herpetologische Bemerkungen.

Jahrbuch der Hamburgischen Wissenschaftlichen Anstalten 2: 82-121.

Inhalt:

Es werden 19 Arten von Schlangen und Echsen beschrieben. Teilweise handelt es sich um Erstbeschreibungen.

fischer-biblio

Eine neue Art der Gattung Bitis (SERPENTES VIPERIDAE) aus Äthiopien.

Monitore Zoologico Italiano. Supplemento, 9:1,59-68, DOI: 10.1080/03749444.1977.10736843.

Zusammenfassung:

Aus dem bewaldeten Bergland SW-Athiopiens wird Bitis parviocula n.sp. beschrieben, eine große, B. nasicornis (Schaw, 1802), B. gabonica (Dumeril, Bibron & Dumeril, 1854) und B. arietans (Merrem, 1820) nahestehende Art. Ihre Merkmale werden hinsichtlich ihrer phylogenetischen Beziehungen und einer wahrscheinlich unterirdischen Lebensweise diskutiert.

böhme-biblio

First record of Brown Snakes Pseudonaja cf. textilis (DUMÉRIL, BIBRON & DUMÉRIL, 1854) from  Papua, Indonesia (Squamata: Serpentes: Elapidae).

HERPETOZOA 15 (1/2): 75-78.

Kurzfassung:

Braunschlangen {Pseudonaja) sind in Australien weit verbreitet und stellen dort eine der medizinisch bedeutsamsten Schlangengattungen dar. Auf der Insel Neuguinea wurden Braunschlangen erstmals 1953 entdeckt. Heute sind sie dort aus einem kleinen Gebiet im Südosten Papua-Neuguineas (Central Province, Milne Bay Province und Oro Province) bekannt. Dieses disjunkte Vorkommen wurde mit einer möglichen unbeabsichtigten Einschleppung während des Zweiten Weltkrieges erklärt. Wir berichten über den Erstnachweis von Braunschlangen - Pseudonaja cf. textilis (DUMÉRIL, BIBRON & DUMÉRIL, 1854) - aus der Gegend um Merauke imSüdosten von Papua (Indonesien), ca. 800 km westlich der bisher bekannten Fundorte. Die Schlangen wurden dort erstmals 1993 gefunden und seitdem regelmäßig gefangen. Mit gegenwärtiger Kenntnis betrachten wir Braunschlangen auf der Insel Neuguinea daher als autochthonen Bestandteil der Fauna und nicht als das Resultat einer kürzlich erfolgten Verschleppung australischer Tiere.

kuch-biblio