Letheobia Cope, 1869

Pyron, Robert Alexander & Wallach, Van, 2014, Systematics of the blindsnakes (Serpentes: Scolecophidia: Typhlopoidea) based on molecular and morphological evidence, Zootaxa 3829 (1), pp. 1-81 : 50-51

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 ).

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Tables

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