Madatyphlops arenarius (GRANDIDIER, 1872)
Can you confirm these amateur observations of Madatyphlops arenarius?
|Higher Taxa||Typhlopidae (Madatyphlopinae), Typhlopoidea, Serpentes, Squamata (snakes)|
|Common Names||Sand Worm Snake|
|Synonym||Onychocephalus arenarius GRANDIDIER 1872: 9|
Typhlops arenarius — BOULENGER 1893: 49
Typhlops arenarius — GLAW & VENCES 1994: 349
Typhlops arenarius — MCDIARMID, CAMPBELL & TOURÉ 1999: 91
Typhlops arenarius — WALLACH et al. 2014: 758
Madatyphlops arenarius — HEDGES et al. 2014
Type locality: “Mouroundava”
|Types||Holotype: MNHN 1895-216|
|Diagnosis||Diagnosis (genus). Species of Madatyphlops have (1) eye, distinct, (2) snout, rounded, (3) head scale arrangement, non-circular, (4) frontorostral, absent, (5) nasal, incompletely (sometimes completely) divided, (6) nasal suture origin, supralabial 2, (7) suboculars or subpreoculars, absent, (8) postoculars, 2–3 (rarely 1 or 4; average, 2.27), (9) preocular-labial contact, supralabials 2 & 3, (10) midbody scale rows, 20–28 (average, 22.9), (11) scale row reduction, present or absent, (12) total scale rows, 252–600 (average, 429), (13) caudals, 6–18 (average, 11.2), (14) maximum total length, 176–600 (average, 320) mm, (15) total length/midbody diameter, 27–85 (average, 45.6), (16) total length/tail length, 33–125 (average, 53.7), (17) dorsal color, usually brown but variable (sometimes white, pink, cream, yellow, gray), (18) ventral color, variable (white, pink, cream, yellow, gray, brown), (19) dorsum darker than venter, (20) overall, usually patternless (rarely with line or yellow nuchal collar) (Tables 1–2); molecular phylo- genetic support (Fig. 1).|
Madatyphlops is distinguished from all genera of Afrotyphlopinae in having fewer postocular scales (2.27 versus 3.68), fewer midbody scales (22.9 versus 24.8), smaller body size (320 versus 403 mm TL), and longer tails (TL/TA = 53.7 versus 68.2; averages). It is distinguished from all genera of Typhlopinae in having more postocular scales (2.27 versus 1.66), more midbody scales (22.9 versus 20.3), more total scale rows (429 versus 369; averages), and larger body size (320 versus 264 mm TL). Madatyphlops is distinguished from individual genera of Asiaty- phlopinae in the following ways: Acutotyphlops has a frontorostral and complete nasal division (versus absent, and suture incomplete), Cyclotyphlops has a circular arrangement of head scales (versus non-circular), Grypotyphlops has suboculars present (versus absent), Indotyphlops has 1 postocular (versus 2–3), Asiatyphlops, Malayotyphlops, and Xerotyphlops have fewer average total scale rows (339, 367, and 355 versus 429), Ramphotyphlops and Sunda- typhlops have longer tails (TL/TA = 31.8 and 33.3 versus 53.7; averages), and Anilios has a solid, awn-like protrusible hemipenis and retrocloacal sacs (versus non-protrusible hemipenis and retrocloacal sacs absent). Xenotyphlop- idae (Xenotyphlops) also occurs on Madagascar, but it differs from Madatyphlops in having a circular rostral scale and single enlarged anal shield (Vidal et al. 2010) [HEDGES et al. 2014: 42]. For an alternative diagnosis see PYRON & WALLACH 2014: 53.
|Comment||Habitat: extremely arid coastal thornbush savannah|
Synonymy: Typhlops boettgeri Boulenger (1893) was recognized as a valid species until 1958 when it was synonymized with T. arenarius by Guibé. These two taxa are perhaps sibling species because they are very similar with considerable variation and overlap in many characters. Typhlops boettgeri exhibits 20–21 midbody scale rows, T. arenarius has 20–24 midbody rows, T. mucronatus has 24–26 midbody rows, and T. decorsei has 26–28 midbody rows; none of the remaining species in Madagascar varies in midbody scale rows.
Sympatry: Typhlops boettgeri and T. arenarius are known to be sympatric from at least four localities (Andrahomana, Mahafaly, Tsimanapetsotsa, and Vohisandria: see Appendix). Typhlops boettgeri can be distinguished from T. arenarius by the following characters: coloration (bicolored with distinct separation of dorsal and ventral colors vs. unicolored), lateral head shape (not depressed and domed vs. depressed and obtusely pointed), dorsal rostral shape (circular vs. parallel), lateral rostral shape (angled vs. curved), position of eyes (prefrontal vs. frontal-prefrontal suture), “X”-shaped cross on head dorsum (absent vs. present), body proportion (< 50 vs. > 50), lateral tongue papillae (present vs. absent), anterior liver lobe extension (0–4% vs. 15–25%), right systemic arch junction craniad of heart tip (5–6% vs. 3–4%), total lung midpoint (29–35% vs. 28–29%), right lung midpoint (40–46% vs. 38–39%), posterior tip of lung (50–62% vs. 47–49%), and total kidney length (8–9% vs. 5–7%). WALLACH & GLAW (2009) therefore do not recognize the synonymy of T. boettgeri and T. arenarius and consider Typhlops boettgeri to be a valid species.
Type species: Onychocephalus arenarius GRANDIDIER 1872: 9 is the type species of the genus Madatyphlops HEDGES et al. 2014: 42.
Type genus: Madatyphlops HEDGES et al. 2014: 42 is the type genus of the subfamily Madatyphlopinae HEDGES et al. 2014: 41.
|Etymology||The generic name is a masculine noun formed from the adjective madagascarianus (a, um; ‘from Madagascar’) and the Greek noun typhlops (the blind).|