If you need an accessible version of this item please contact JSTOR User Support

Systematics of the Eastern Ratsnake Complex (Elaphe obsoleta)

Frank T. Burbrink
Herpetological Monographs
Vol. 15 (2001), pp. 1-53
Published by: Herpetologists' League
DOI: 10.2307/1467037
Stable URL: http://www.jstor.org/stable/1467037
Page Count: 53
  • Download PDF
  • Cite this Item

You are not currently logged in.

Access your personal account or get JSTOR access through your library or other institution:

login

Log in to your personal account or through your institution.

If you need an accessible version of this item please contact JSTOR User Support
Systematics of the Eastern Ratsnake Complex (Elaphe obsoleta)
Preview not available

Abstract

The eastern ratsnake, Elaphe obsoleta currently includes seven highly variable and taxonomically confusing subspecies. Recently, maximum likelihood and maximum parsimony phylogenetic analyses of two mitochondrial gene sequences suggested that the complex of E. obsoleta (including E. bairdi) is composed of four distinct evolutionary lineages found in four geographical areas: 1) an eastern clade located east of the Apalachicola River and the Appalachian Mountains, 2) a central clade located west of the Apalachicola River and the Appalachian Mountains and east of the Mississippi River, 3) a western clade located west of the Mississippi River, and 4) E. bairdi is located in southwest Texas and northeastern Mexico. With respect to this phylogeographic hypothesis, the former seven subspecies of E. obsoleta do not represent distinct evolutionary lineages. In this paper, the morphology of Elaphe obsoleta and E. bairdi is compared to the results of the previous molecular study. Univariate and multivariate analyses of 67 morphological characters scored from 1006 specimens provided statistical support for the recognition of the same four evolutionary lineages identified in the phylogeographic study. Specimens can be classified morphologically by using canonical discriminant function analysis into the four molecular clades more accurately than they can be grouped into subspecific categories. Moreover, the identification of these subspecies proved difficult when using the traditional characters ascribed to them. In light of the corroborating molecular and morphological evidence, it is suggested that the recognition of the subspecies of E. obsoleta be discontinued. Instead, the four molecular clades should be recognized as four species: 1) eastern clade = E. alleghaniensis, 2) central clade = E. spiloides, 3) western clade = E. obsoleta, and 4) E. bairdi = E. bairdi.

Page Thumbnails

  • Thumbnail: Page 
1
    1
  • Thumbnail: Page 
2
    2
  • Thumbnail: Page 
3
    3
  • Thumbnail: Page 
4
    4
  • Thumbnail: Page 
5
    5
  • Thumbnail: Page 
6
    6
  • Thumbnail: Page 
7
    7
  • Thumbnail: Page 
8
    8
  • Thumbnail: Page 
9
    9
  • Thumbnail: Page 
10
    10
  • Thumbnail: Page 
11
    11
  • Thumbnail: Page 
12
    12
  • Thumbnail: Page 
13
    13
  • Thumbnail: Page 
14
    14
  • Thumbnail: Page 
15
    15
  • Thumbnail: Page 
16
    16
  • Thumbnail: Page 
17
    17
  • Thumbnail: Page 
18
    18
  • Thumbnail: Page 
19
    19
  • Thumbnail: Page 
20
    20
  • Thumbnail: Page 
21
    21
  • Thumbnail: Page 
22
    22
  • Thumbnail: Page 
23
    23
  • Thumbnail: Page 
24
    24
  • Thumbnail: Page 
25
    25
  • Thumbnail: Page 
26
    26
  • Thumbnail: Page 
27
    27
  • Thumbnail: Page 
28
    28
  • Thumbnail: Page 
29
    29
  • Thumbnail: Page 
30
    30
  • Thumbnail: Page 
31
    31
  • Thumbnail: Page 
32
    32
  • Thumbnail: Page 
33
    33
  • Thumbnail: Page 
34
    34
  • Thumbnail: Page 
35
    35
  • Thumbnail: Page 
36
    36
  • Thumbnail: Page 
37
    37
  • Thumbnail: Page 
38
    38
  • Thumbnail: Page 
39
    39
  • Thumbnail: Page 
40
    40
  • Thumbnail: Page 
41
    41
  • Thumbnail: Page 
42
    42
  • Thumbnail: Page 
43
    43
  • Thumbnail: Page 
44
    44
  • Thumbnail: Page 
45
    45
  • Thumbnail: Page 
46
    46
  • Thumbnail: Page 
47
    47
  • Thumbnail: Page 
48
    48
  • Thumbnail: Page 
49
    49
  • Thumbnail: Page 
50
    50
  • Thumbnail: Page 
51
    51
  • Thumbnail: Page 
52
    52
  • Thumbnail: Page 
53
    53