Tricheilostoma joshuai ( Dunn 1944 )

Pinto, Roberta Richard, Passos, Paulo, Portilla, José Rances Caicedo, Arredondo, Juan Camilo & Fernandes, Ronaldo, 2010, Taxonomy of the Threadsnakes of the tribe Epictini (Squamata: Serpentes: Leptotyphlopidae) in Colombia, Zootaxa 2724, pp. 1-28 : 7-10

Tricheilostoma joshuai ( Dunn 1944)

Figs. 4, 5

Leptotyphlops joshuai Dunn 1944 , Caldasia 3:53.

Leptotyphlops joshuai— Bailey 1946, Occasional Papers of the Museum of Zoology the University of Michigan, 492:4. Leptotyphlops joshuai— Dunn 1946, Caldasia, 4:122.

Leptotyphlops joshuai— Peters & Orejas-Miranda 1970, Bulletin of the United States National Museum, 297:170. Leptotyphlops joshuai— Hahn 1980, Das Tierreich, 101:19.

Leptotyphlops joshuai— McDiarmid, Campbell & Touré 1999, Snakes Species of the World, 1:33–34. Leptotyphlops joshuai— Passos, Caramaschi & Pinto 2006, Amphibia-Reptilia, 27:349. Tricheilostoma joshuai— Hedges, Adalsteinsson & Branch in Adalsteisson et al. 2009, Zootaxa, 2244:11.

Holotype. MLS 13, from municipality of Jericó (05o 47' N, 0 75o 47' W; ca. 1967 m), department of Antioquia, Colombia (see remarks).

Paratypes: MLS 11, MLS 2646–2647 from municipality of Jericó, department of Antioquia. MLS 12 from “Río Cauca”, department of Antioquia. MLS 14 lacking specific locality, department of Antioquia. MLS 15 from Villamaría (05o 62' N, 0 75o 31' W; ca. 1840 m), department of Caldas, Colombia.

Diagnosis. Tricheilostoma joshuai is distinguished from all congeners by the following combination of characters: snout rounded in dorsal view, truncate in lateral view; supraocular present; rostral triangular in dorsal view; ocular subhexagonal, with rounded shape in the eye level; temporal distinct; fused caudals; eye in anterior portion of expanded area of ocular scale; three supralabials (2+1); four infralabials; 174–193 middorsal scales in males and 184–199 in females; 169–181 midventral scales in males and 172–187 in females; 13–17 subcaudals in males and 13–15 in females; 12 scales around the middle of tail; seven dark brown dorsal scale rows with pale brown edge, venter and labial scales cream.

Redescription of the holotype. Adult female, 259 mm TL, 16 mm TAL; 8.3 mm MB; 16.2 TL/TAL; 31.2 TL/ MB; 4.9 mm HL; 3.0 mm relative eye diameter; 0.3 mm relative rostral width; head slightly depressed; body subcylindrical, slightly enlarged on head and slightly tapered caudally near the tail.

Head subcylindrical, almost twice as long as wide; cervical constriction barely distinct; snout slightly truncate in dorsal and ventral views, slightly obtuse in lateral view; rostral straight in frontal and ventral views, dorsal apex triangular, reaching an imaginary transverse line between anterior margins of ocular scales; rostral contacting supranasal and infranasal laterally and frontal dorsally; nasal completely divided horizontally by oblique suture crossing nostril; nostril roughly elliptic, obliquely oriented and placed in the middle of the nasal suture; supranasal about twice as high as long, bordering rostral anteriorly, infranasal inferiorly, first supralabial and ocular posteriorly, and frontal and supraocular dorsally; supranasal as long as upper border of infranasal scale; infranasal about twice as high as long; upper lip border formed by rostral, infranasal, two anterior supralabials, ocular and posterior supralabial scales; temporal scale distinct from dorsal scales of lateral rows; three supralabials (five according to Dunn 1944), two anterior and one posterior to ocular (2+1); first supralabial small, not reaching level of nostril and eye; second supralabial about twice as high as long, exceeding nostril and the lower portion of eye level; third supralabial with trapezoidal shape, lower than second one, slightly longer than high, reaching eye level, its posterior margin in broad contact with temporal; ocular enlarged, subhexagonal, rounded in the eye level, twice as high as long, contacting the posterior margins of supranasal and second supralabial anteriorly, parietal and third supralabial posteriorly, and supraocular dorsally, its dorsal apex straight; eye distinct (0.6 mm), placed in the anterior area of the expanded upper part of ocular, displaced above the nostril level; supraocular three times longer than wide, subtly longer and slender than frontal scale, contacting supranasal anteriorly, frontal, postfrontal and ocular scales laterally, and parietal posteriorly; midsaggital head scales (postfrontal, interparietal and interoccipital) subequal in size, hexagonal in dorsal view, weakly imbricate; frontal not enlarged, smaller than other midsaggital scales, as wide as long, contacting rostral and supranasals anteriorly, supraoculars laterally, and postfrontal posteriorly; postfrontal as wide as long, contacting frontal, supraoculars, parietals and interparietal; interparietal wider than long, contacting postfrontal, parietals, occipitals, and interoccipital; interoccipital contacting interparietal, occipitals, and the first dorsal scale of the vertebral row; parietal and occipital similar in shape, irregularly pentagonal; parietal twice as wide as long, lower margin contacting the upper border of third supralabial, posterior margin contacting temporal, occipital and interparietal, anterior border in broad contact with ocular, supraocular and postfrontal; occipital twice as wide as long, its lower limit not attaining the level of the upper margin of third supralabial, though separated of the latter by temporal; symphysial trapezoidal, anterior and posterior borders respectively straight and slightly convex, three times as wide as long; four infralabials behind symphysial on both sides; first three infralabials subequal, slightly higher than long; fourth longer than other infralabials, approximately as long as second one; dorsal scales homogeneous, cycloid, smooth, slightly imbricate, and almost two times as wide as long; 195 (191 according to Dunn 1944) middorsal scales; 181 midventral scales; 14 scale rows around midbody, reducing to 12 rows in the middle of the tail; cloacal shield short and semicircular, wider than long; 15 subcaudals; caudals fused; terminal spine short, conical, with stout base, longer than wide.

Colour of the holotype in preservative: Seven dorsal scale rows uniformly dark brown and seven ventral scale rows cream; head dorsally paler than dorsal scales of body, with some brown pigmentation concentrated on centre portion of cephalic scales; paler colour extending from rostral to interoccipital; lower margins of scales forming the creamish upper lip border; cloacal shield pale brown, slightly darker than general ventral coloration; terminal spine not pigmented.

Sexual dimorphism: Females were significantly longer (F(1,13) = 11.8; p <0.01) and showed a higher TL/TAL ratio (F(1, 13) = 7.1; p <0.05) than males. However, males have significantly more subcaudal scales (F(1,13) = 11.2; p <0.01) and largest tail F(1, 13) = 8.1; p <0.01) than females.

Variation: Middorsal scales 174–193 (x¯ = 187.4 ± 5.2, n = 10) in males and 184–199 (x¯ = 193.8 ± 6.7, n = 4) in females; midventral scales 169–181 (x¯ = 173.9 ± 4.2, n = 8) in males and 172–187 (x¯ = 180.0 ± 7.6, n = 3) in females; subcaudal scales 13–17 in males (x¯ = 16.0 ± 1.2, n = 10) and 13–15 (x¯ = 13.8 ± 1.1, n = 5) in females; TL 90–218 mm (x¯ = 149.3 ± 49.5, n = 10) in males and 163–300 mm (x¯ = 246.2 ± 55.6, n = 5) in females; TL/TAL ratio 10.8–17.0 (x¯ = 13.1 ± 1.9, n = 10) in males and 13.6–24.6 (x¯ = 17.3 ± 4.3, n = 5) in females; TAL 5.9–9.3% of TL in males (x¯ = 7.8 ± 0.0, n = 10) and 4.1–7.4% in females (x¯ = 6.0 ± 0.0, n = 5); TL/MB ratio 37.8–50.0 (x¯ = 42.3 ± 4.2, n = 10) in males and 34.0–55.2 (x¯ = 43.9 ± 9.4, n = 5) in females; TAL/MT ratio 2.8–3.6 (n = 2) in males and 2.9–3.5 (x¯ = 3.2 ± 0.3, n = 3) in females; relative eye diameter 0.3–0.4 (n = 2) in males and 0.4–0.5 (x¯ = 0.5 ± 0.0, n = 3) in females; rostral width 2.4–3.7 (n = 2) in males and 2.1–2.3 (x¯ = 2.2 ± 0.1, n = 3) in females.

Distribution. Cauca valley between the Cordilleras Occidental and Central of Colombia, from Jericó (05º47’39”N, 75º47’23”W), department of Antioquia south to San Antonio (03º13’N, 76º39’W), department of Valle del Cauca; between altitudes of 1600 up to 2200 m ( Fig. 3 ).

Remarks. Dunn (1944) described Leptotyphlops joshuai on the basis of seven specimens from the Cauca Valley. However, the author did not provide the institutional number for all specimens in the type series. Although La Salle types actually are kept together in a separate cabinet from remaining collection, the specimen currently labelled as holotype did not match with morphometric and meristic data given in the original description. As most of the bottles and labels in the La Salle collection were replaced after the fire accident in 1948 (frequently without the maintenance of the original species label), many types were mixed with specimens from the main collection or lost (P. Passos pers. obs.). Besides, the specimen separated in the type’s cabinet (MLS 11) was not labelled as such, while other leptotyphlopid types were properly labelled (e.g., L. brevissimus and L. nicefori ). In this context, we here propose the recognition of MLS 13 as the holotype based on the similarity of morphometric and meristic data with the original description.

Figures

FIGURE 3. Geographic distribution of species of the tribe Epictini in Colombia. Type localities correspond to white symbols.

FIGURE 5. Dorsal (A), lateral (B), and ventral (C) views of head of the Tricheilostoma joshuai (MVZ 68688).