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Phylogenetic relationships of old world ratsnakes based on visceral organ topography, osteology, and allozyme variation

(by Notker Helfenberger, a review by Rex Knight)

Recently Mr. N. Helfenberger published his most recent work on the Elaphe complex in the Russian Journal of Herpetology. (Supplement to the Journal, ISSN 1026-2296). This paper is 62 pages long and contains several tables and charts, diagrams of "likelihood trees" and some diagrams of vertebral structures. There are no photographs, except the cover, which shows five preserved specimens arranged together for the photo titled "Pedigree Required".

Foreword: Phylogenetic relationships of 30 species and subspecies of Old World ratsnakes, are estimated using visceral topography, vertebrae and allozyme variation. Distances between the taxa were calculated from positions and lengths of vertebra, and frequencies or proteins encoded by 19gene loci. The Indo-Malayan species group with conservative features has large phylogenetic distances to the Euro-Mediterranean and Siberian, and to the East and High Asian species. The latter cluster exhibits parallel evolution with species from the Euro-Mediterranean and Siberian region.
The East Asian Elaphe rufodorsata and the Mediterranean Elaphe scalaris show derived features and large distances to related taxa.
This study represents a step towards a definitive reconstruction of phylogenetic relationships within Old World Elaphe species.
The geographical terms used are from Banarescu, (1992).

There are several chapters including "Material and Methods", "Results", "Discussion", "Conclusions", "Taxonomic changes" and "Summary".

Species of Elaphe used for this study include Elaphe bellaE. bimaculata, E. cantoris, E. carinata, E. climacophora, E. conspicillata, E. davidi, E. dione, E. erythrurus, E.flavolineata, E. frenata, E. helena, E.hodgsoni, E. hohenackeri, E. janseni, E. longissima, E. mandarina, E. moellendorffi, E. persica, E. porphyracea, E. quadrivirgata, E. quatuorlineata, E. radiata, E. schrencki, E. situla, E. subradiata, and E. taeniura. Elaphe perlacea was not listed. Mr. Helfenberger also used more than just species of Elaphe for this study, also included were specimens of the Genus Coronella, Gonyosoma, Hierophis, and Ptyas for comparisons.
I'm not going to get into all of this, as far as discussions, but rather just give you the main changes within this work. If you need to know more of the technical aspects of this paper, I will include information below on obtaining a copy.

The species are broken into different groups based on the methods used.

The Mediterranean and Siberian taxa result in three different groups or branches: 
1. "Quatuorlineata group" which includes E. quatuorlineataE. anomalaE. dioneE. sauromates, and E. schrencki
He states that "Genetic distances" argue for Specific status of E. anomala and E. sauromates
2. The "Longissima group", which includes E. longissima, E. hohenackeriE. persica, and E. situla
3. Rhinechis scalaris, stating that scalaris is outstanding with large distances from the other groups and is therefore separated from the Elaphe Genus. He further states that this species should be compared to racers of the genera Coluber and Hierophis.

East and High Asian taxa result in four groups: 
1. The "Moellendorffi-group", which includes E. moellendorffi , E. cantoris, E. frenata, E. hodgsoni, E. mandarina, E. prasina,and E. taeniura
2. The "Carinata group" which includes E. carinata, E. davidi, and E. quadrivirgata
3. The "Porphyracea group" which includes E. porphyracea and E. conspicillata
4. The "Climacophora group" which includes E. climacophora and E. bimaculata.

He states here that the "Climacophora group also shows close affinities to the Quatuorlineata group." Also, "the molecular data suggest that the Euro-Mediterranean and Siberian groups evolved slowly from a common ancestor shared with the East and High Asian species, which evolved rapidly."

Oocatochus rufodorsatus: "In all investigated aspects, the egg-retending, semiaquatic O. rufodorsata is outstanding", and is removed from the Elaphe genus. He states that "this species probably split from a common ancestor shared with East and High Asian Elaphe and evolved rapidly". The name Oocatochus is derived and "latinised" from the Greek words "oon" = egg and "katochos" = retending, egg-retending.

Gonyosoma is accepted as a valid Genus and includes G. janseni and G. oxycephala.

Coelognathus: C. erythrurus, C. flavolineata, C. helena, C. radiatus, and C. subradiatus the Indo-Malayan species (formerly E. erythrurus, E. flavolineata, E. helena, E. radiatus, and E. subradiatus) are separated from the Elaphe Genus and referred to the revalidated Genus Coelognathus. This name was first used by Fitzinger for radiatus in 1843. He states here that Coelognathus species evolved slowly compared to Asian Elaphe, and also that Gonyosoma and Coelognathus show affinities to the Elaphe moellendorffi-group.

Now remember these groups are based on the methods used: organ topography, vertebrae, Phylogenetic Analysis and such. You may be like me and when you read that E. prasina and E. frenata are grouped with E. moellendorffi, you think "How can this be?!" But these are the findings from his study, and I'm sure this is not the last word on the very complex Elaphe Genus. I fully agree with all the taxonomic changes herein, but I, like most of you, have my own ideas, and with keeping and working with both E. conspicillata and E. mandarina, I see them more related than E. mandarina and E. moellendorffi. BUT, again, the methods used…..

A note on other works, Urs Utiger of the Zoological Museum, Zurich, Switzerland recently completed a mtDNA study of the three endemic Elaphe species of Japan and found that the construed trees show a close relationship between E. climacophora and E. quadrivirgata with each other and to the mainland species E. carinata. The distance of E. conspicillata to the other Japanese species as well as mainland species was very large. Stating that "the possibly close relationship of E. climacophora and E. quadrivirgata with palearctic mainland species is explained by a scenario in which their ancestors crossed the unique land bridge between Korea and Southwest Japan in the Pleistocene, 160,000 years ago, while the ancestor of E. conspicillata reached the islands long ago, most likely in tertiary times." And speaking of the "Last Word" on the Elaphe, there are three more works to be published in the near future. Two separate studies based on DNA sequences (nuclear and mitochondrial genes) and a study of the hemipenial morphology of Old and New World Elaphe.

Ultimo aggiornamento Domenica 21 Novembre 2010 22:22