Leptotyphlops nigricans (SCHLEGEL, 1839)
Can you confirm these amateur observations of Leptotyphlops nigricans?
|Higher Taxa||Leptotyphlopidae, Leptotyphlopinae, Leptotyphlopini, Typhlopoidea, Serpentes, Squamata (snakes)|
|Common Names||E: Black Thread Snake|
|Synonym||Typhlops nigricans SCHLEGEL 1839: 38|
Leptotyphlops nigricans — FIT ZINGER 1843
Stenostoma nigricans — DUMÉRIL & BIBRON 1844: 326
Glauconia nigricans — GRAY 1845: 139
Stenostoma nigricans — JAN 1861
Stenostoma nigricans — BOCAGE 1866: 46
Glauconia nigricans — BOULENGER 1893: 67
Leptotyphlops nigricans — SCHMIDT 1923
Leptotyphlops nigricans nigricans — BROADLEY & WATSON 1976: 490
Leptotyphlops nigricans — MCDIARMID, CAMPBELL & TOURÉ 1999: 39
Leptotyphlops nigricans — BROADLEY & WALLACH 2007: 60
Leptotyphlops nigricans — ADALSTEINSSON, BRANCH, TRAPE, VITT & HEDGES 2009
Leptotyphlops nigricans — WALLACH et al. 2014: 368
|Distribution||S Republic of South Africa (Western and Eastern Cape Provinces) (BROADLEY 1999: 16-17), Republic of South Sudan (RSS)|
Type locality: Cape of Good Hope, South Africa.
|Types||Syntypes: MNHN-RA 3232, RMNH, ZMB 5244|
|Diagnosis||Diagnosis (genus): Species of Leptotyphlops have 14 midbody scale rows, 10–12 midtail scale rows, 171–322 middorsal scale rows, 18–44 subcaudals, two supralabials, a small anterior supralabial (moderate in L. howelli), 126–292 mm maximum adult total length, a body shape of 36–106 (total length/width), a relative tail length of 5.1–13.7 %, a tail shape of 3.4–9.2, no striped pattern, and usually a dark brown or brown dorsum and venter (Table 2). Members of Leptotyphlops can be distinguished from the other genus in the Tribe Leptotyphlopini (described below) by having a heart-shaped or subtriangular (rather than semilunate) cloacal shield, a lower number (on average) of middorsal scales (171–322 versus 241–387), and a less attenuate body shape (36–106 versus 45–142). The support for this group was 100% BP and 100% PP for the four-gene tree (Fig. 3) and 100% BP and 100% PP for the nine-gene tree (Fig. 4). [from ADALSTEINSSON et al. 2009].|
Diagnosis (family). Small and thin snakes sharing with other members of Scolecophidia cylindrical bodies, ventral scales not enlarged, reduced eyes with a single visual cell type in the retina, and the absence of neural spines. They have solidly constructed skulls with toothless premaxillary, maxillary, and palatine bones sutured to the braincase along with the nasals and prefrontals. They lack a left lung, a tracheal lung, and a left oviduct (Dowling & Duellman 1978; Underwood 1967; Vitt & Caldwell 2009). Except for two species having 16 midbody scale rows and two others having 14 or 16 rows, all of the other members of the family usually have 14 midbody scale rows. The maximum adult size of each species ranges from 104 mm (Leptotyphlops carlae) to 460 mm (Rhinoleptus koniagui) in total length; see discussion of body size in leptotyphlopid snakes (Hedges 2008) [from ADALSTEINSSON et al. 2009].
|Comment||Distribution: According to Wallach 1996 not known from Kenya. Leptotyphlops nigricans is not listed by BROADLEY & POYNTON 1998 for the Democratic Republic of the Congo (Zaire). Hahn 1980 gave as range “Southern Cape Province from Calvinia to lower Transkei; central Transvaal; central Zambia through eastern Angola, eastern Zaire, Rwanda, Tanzania; Kenya and Uganda to the southern Sudan.” The record from Calvinia (Peters, 1882) was based on L. gracilior (BROADLEY 1999). LARGEN & RASMUSSEN 1993 listed this species for Ethiopia.|
Synonymy: SCHMIDT’s (1923) Leptotyphlops nigricans seems to be L. emini (fide ROUX-ESTEVE 1975). Kaiser et al. 2013 considered the generic names Karimdaouesus Hoser 2012, Ottobreus Hoser 2012, Teesleptotyphlops Hoser 2012, Bobbottomus Hoser 2012 invalid and rejected their use instead of Leptotyphlops.
Subspecies: Leptotyphlops nigricans pembae has been elevated to species status.
Type species: Typhlops nigricans SCHLEGEL 1839 is the type species of the genus Leptotyphlops Fitzinger, 1843. Leptotyphlops is the type genus of the family Leptotyphlopidae.
Key to genera: Martins et al. 2020 provide a key to the genera of New World Leptotyphlopidae.
Key to species in NE Africa and SW Arabia: (Broadley & Wallach 2007: 70)
Phylogenetics: Martins et al. 2020 provide a phylogenetic analysis of Leptotyphlopidae and classify them into 4 tribes, Leptotyphlopini, Myriopholini, Epictini, and Rhinoleptini.
Type genus: Leptotyphlops Fitzinger, 1843 is the type genus of the family Leptotyphlopidae Stejneger, 1892 and the type genus of the subfamily Leptotyphlopinae (see Adalsteinsson et al. 2009: 25).
|Etymology||Named after the dark color of the species.|
The generic name is masculine and derived from the Greek adjective leptos (thin) and Greek noun typhlops (blind), in allusion to the attenuate body shape and reduced vision of these snakes.