Systematics of the blindsnakes (Serpentes: Scolecophidia: Typhlopoidea) based on molecular and morphological evidence
Author
Pyron, Robert Alexander
Author
Wallach, Van
text
Zootaxa
2014
3829
1
1
81
journal article
36820
10.11646/zootaxa.3829.1.1
a4b69269-5a4c-4b5b-9f89-6b314d3ba284
1175-5326
286556
75210CDC-AC6A-4624-A6F1-1BC969BC7CAA
Letheobia
Cope, 1869
Type
species.
Onychocephalus caecus
Duméril, 1856
Species content.
Letheobia acutirostrata, Let.
caeca, Let.
crossii, Let.
debilis,
Let.
episcopus, Let.
erythraea,
Let.
feae, Let.
gracilis, Let.
graueri, Let.
jubana, Let.
kibarae, Let.
largeni, Let.
leucosticta, Let.
lumbriciformis,
Let.
newtoni, Let.
pallida, Let.
pauwelsi, Let.
pembana, Let.
praeocularis, Let.
rufescens,
Let.
simoni, Let.
somalica, Let.
stejnegeri, Let.
sudanensis, Let.
swahilica, Let.
toritensis, Let.
uluguruensis
,
and
Let
.
wittei
.
Diagnosis.
Letheobia
can be distinguished from all other typhlopoids by the combination of the following characters: T-0 or T-II
SIP
, lateral snout profile rounded, gracile body form, eye invisible or reduced to faint spot, and coloration pink (pigmentless). Small- to large-sized (total length
106–550 mm
), moderate- to slender-bodied (length/width ratio 42–129) snakes with 18–30 scale rows (with or without reduction), 336–737 total middorsals, short to moderate tail (0.7–2.6% total length) with 5–17 subcaudals (length/width ratio 0.6–2.0), and apical spine absent or bare nubbin. Dorsal and lateral head profiles rounded, moderate to broad rostral (0.36–0.83 head width), inferior nasal suture in contact with first or second supralabial (and rarely, rostral), preocular in contact with second or second and third supralabials, subocular present or absent, and postoculars 2–6. Lateral tongue papillae absent; left lung absent, tracheal lung multicameral (with 17–45 chambers), cardiac lung multicameral (with 3–8 chambers), paucicameral (with 1–9 pockets) or unicameral and right lung unicameral, paucicameral (with 2–5 pockets) or multicameral (with 2–21 chambers); testes segmented or unsegmented; hemipenis eversible, lacking retrocloacal sacs; rectal caecum small to large (0.5–6.3% SVL) or absent.
Phylogenetic definition.
Includes the MRCA of
Letheobia episcopus
and
Let
.
feae
and all descendants thereof, and all species more closely related to
Let
.
caeca
than to the
type
species of the 16 other typhlopid genera listed here.
Etymology.
Possibly a reference to the river Lethe in Hades, associated with the Greek spirit of forgetfulness and oblivion.
Distribution.
Ranges across most of the central and eastern portion of sub-Saharan Africa, with some species in
Turkey
(
Letheobia episcopus
) and the Middle East (
Let
.
simoni
).
Remarks.
Note that the West African species
Typhlops coecatus
and
T. zenkeri
were moved to
Letheobia
by
Hedges
et al.
(2014)
, but we suggest they are not allied with this group. They resemble
Typhlops
based on the preocular shape, 18–20 scale rows, narrow rostral, and primitive unicameral lung system, as do several of the examined Caribbean
Typhlops
(
T. hectus
,
T. monensis
,
T. pusillus
,
and
T. rostellatus
). We thus restore them to
Typhlops
. Those authors also placed
Let
.
jubana
in
Afrotyphlops
, but this species is clearly allied with
Letheobia
on the basis of faint or absent eyespot, absence of left lung and other visceral measurements (
Table 6
).
TABLE 6.
Visceral character states comparing
Letheobia jubana
and
Let
.
leucosticta
with
Afrotyphlops
(
AFR
)
and
Letheobia
(
LET
),
based on measurement of the specimens in Appendix II (part). Characters are as follows: data in sections
(A)-(D)
represent sample means as % SVL; organ lengths (PT = posterior tip) are included in section
(A)
; organ midpoints (MP) are listed in section
(B)
; organ gaps (GAP) and intervals (INT) are compiled in section
(C)
; organ midpoint intervals (MP-MP INT) are included in section
(D)
; meristic values are listed in section
(E)
; ratios of two characters listed in
(F)
.
| Taxon |
AFR
|
jubana
|
LET
|
leucosticta
|
| Sample size |
n
= 150
|
n =
5
|
n
= 84
|
n =
1
|
| (A) |
| Hyoid PT |
12.4 |
8 |
6.3 |
8.7 |
| Heart |
4.5 |
4 |
3.6 |
5.5 |
| Right kidney |
4 |
3.5 |
3.3 |
3.9 |
| Left kidney |
3.8 |
3.3 |
3.2 |
4.6 |
| Total (left + right) kidney |
7.8 |
6.9 |
6.6 |
8.5 |
| Rectal caecum |
2.9 |
1.6 |
1.9 |
1.4 |
| Trachea |
34.6 |
27.8 |
28.7 |
33 |
| Tracheal lung |
22.1 |
11.8 |
16.8 |
20.6 |
| Right lung PT |
53.6 |
43.6 |
47.2 |
45.3 |
| Right bronchus |
3.4 |
7.1 |
7.3 |
4.1 |
| Right bronchus PT |
39.4 |
35.8 |
36.8 |
38.4 |
| Trachea + bronchus |
38 |
34.9 |
36 |
37.1 |
| (B) |
| Heart MP |
33.7 |
26.7 |
27.7 |
31.6 |
| Total (left + right) liver MP |
49 |
41.3 |
44.4 |
45.4 |
| Right kidney MP |
80.3 |
83.8 |
85.6 |
89.4 |
| Left kidney MP |
82.6 |
87.4 |
87.4 |
90.6 |
| Total (left +right) kidney MP |
81.5 |
85.6 |
86.5 |
90 |
| Trachea MP |
18.7 |
14.8 |
15.1 |
17.8 |
| Right lung MP |
44.8 |
36.2 |
38.4 |
39.8 |
| Trachea + bronchus MP |
20.4 |
18.3 |
18.8 |
37.1 |
| Tracheal lung MP |
20.2 |
13.8 |
17.3 |
19.9 |
| (C) |
| Snout-heart INT |
36 |
28.7 |
29.5 |
34.3 |
| Heart-gall baldder GAP |
27.3 |
33.5 |
36.8 |
32 |
| Liver-gall bladder GAP |
2.1 |
9.1 |
7.5 |
7.3 |
| Liver-gall bladder INT |
27 |
33.9 |
36 |
31.6 |
| Liver-kidney GAP |
17.2 |
29.5 |
25.2 |
28.4 |
| Liver-kidney INT |
46.5 |
58.8 |
57.5 |
61.1 |
| Gall bladder-kidney GAP |
13.3 |
18.3 |
16.5 |
19.5 |
| Kidney-vent GAP |
15.4 |
11 |
11 |
7.1 |
| Kidney-vent INT |
21.6 |
17.9 |
16 |
12.6 |
.
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