Typhlops tycherus, Townsend & Wilson & Ketzler & Luque-Montes, 2008

Townsend, Josiah H., Wilson, Larry David, Ketzler, Lorraine P. & Luque-Montes, Ileana R., 2008, The largest blindsnake in Mesoamerica: a new species of Typhlops (Squamata: Typhlopidae) from an isolated karstic mountain in Honduras, Zootaxa 1932 (1), pp. 18-26 : 20-23

Typhlops tycherus new species

( Figs. 2 , 3 )

Holotype. Adult female ( UF 151797), on road between San José de Los Andes and El Cedral (14°54.241’N, 88°05.489’W), 1550 m elevation, western slope of Montaña de Santa Bárbara ( Fig. 4 ), Parque Nacional Montaña de Santa Bárbara, Depto. Santa Bárbara, Honduras, collected 3 February 2008 by Laura E. Chakerian and Lorraine P. Ketzler, original field number JHT 2376.

Diagnosis. Typhlops tycherus can be most readily distinguished from all other snakes in the mainland of the Western Hemisphere based on the number of scale rows around the body (22); all other Typhlops found in the mainland of the Western Hemisphere have 18–18–18 ( T. amoipira , T. microstomus , T. paucisquamis , T. stadelmani , T. tenuis and T. yonenagae ), 20–20–20 ( T. brongersmianus , T. costaricensis , T. lehneri , T. reticulatus , and T. trinitatus ), or 20–18–16 or 18–16–14 ( T. minuisquamis ). Of the Mesoamerican Typhlops , T. tycherus is further differentiated as follows: from T. costaricensis by having a well-defined pale yellowish gray to immaculate white venter (venter somewhat lighter but grading into dorsal coloration throughout most of the body with yellowish gray or unpigmented scales restricted to chin and throat and posterior portion of body, with scattered pale spots along the midventral line in T. costaricensis ); from T. microstomus by having fewer dorsal scales between the rostral and tail tip (395, versus 487–566 in T. microstomus ), a relatively longer tail (TL/TTL = 1.51, versus 0.37–1.36 in T. microstomus ) and by lacking a subocular; from T. stadelmani in having more dorsal scales between the rostral and tail tip (395, versus 341–369 in T. stadelmani ) and larger maximum total length (371 mm, versus 310 mm in T. stadelmani ); and from T. tenuis in lacking spots on median dorsal scale rows (dorsal spots present on at least median scale rows in T. tenuis ) and having larger maximum total length (371 mm, versus 326 mm in T. tenuis ). Additional comparative data, measurements, and ratios for the Mesoamerican Typhlops are given in Table 1. From the South American species (other than T. lehneri , which has 18–18–18 scales around the body), T. tycherus is further distinguished by having a completely divided nasal with the suture contacting the rostral (nasal not completely divided in T. amoipira , T. brongersmianus , T. reticulatus , T. trinitatus , T. paucisquamis , and T. yonenagae ). In the Western Hemisphere outside of Mesoamerica and South America, T. tycherus most closely resembles the 11 members of the T. biminiensis species group from the Bahamas, the Cayman Islands, and Cuba, from which it may be distinguished as follows: having 22–22–22 scales around the body (26–24– 24 in T. arator and 20–20– 20 in T. caymanensis ) and 395 scales between rostral and tail tip (453–579 in T. anchaurus , T. anousius , T. biminiensis , T. contorhinus , T. epactius , T. notorachius , T. paradoxus , T. perimychus , and T. satelles ).

Description. A large Typhlops , total length 371 mm, tail length 5.6 mm; 22–22–22 scales around body; 395 dorsal scales between rostral and tail tip; subcaudals 8; head width at level of eye 6.3 mm; anterior body width 7.6, midbody width 9.1, posterior body width 8.7 mm; tail length 1.51% of total length; mid-tail width 5.6 mm; rostral length 2.9 mm, width 2.1 mm, reaching posteriorly to level of anterior edge of eyespots, widest point about halfway between tip of snout and posterior tip of rostral; rostral bordered by two prefrontals that extend posteriorly beyond tip of rostral; nasal suture complete, dividing anterior and posterior nasals; inferior nasal suture contacts second supralabial; eye diameter 0.4 mm; eye-nostril distance 2.3 mm; interor- bital distance 4.2 mm, 66.7% of head width; parietals 2/2, anterior parietals cycloid, bordered posteriorly by second pair of wide, narrow occipitals; occipitals spanning about two dorsal scales; frontal contacted at posterior apex by two small scales that interrupt contact between occipitals; 4/4 supralabials, becoming large posteriorly; second and third supralabials contacting preocular; supralabial imbrication pattern T-III; preoculars about twice as high as wide, contacting anterior edge of eye spot; ocular about twice as high as wide at maximum; mental small, roughly equal in size to adjacent infralabials and chin scales; infralabials 4/4, roughly equivalent in size to each other and adjacent scales.

Dorsal color in preservative uniform dark brownish-gray, pigmented dorsal scale rows number from 13 to 19; some pale yellowish gray coloration around nostrils and on anteriormost portions of the head, ventral surface pale yellowish gray anteriorly, becoming immaculate white on posterior half of body; ventral coloration abruptly differentiated from dorsal coloration, extending unbroken for full length of body; unpigmented ventral region ranges from three to nine scales in width, uninterrupted throughout length of body, becoming broadest towards posterior end of body.

Distribution. The single known specimen of Typhlops tycherus ( Fig. 3 ) was found dead on the road at 1550 m elevation in the Zona de Amortiguamiento (buffer zone) of Parque Nacional Montaña de Santa Bárbara, between two small communities at the lower edge of the cloud forest in early February. This locality lies in the Lower Montane Wet Forest formation ( Holdridge, 1967; McCranie & Wilson, 2002), where the habitat comprises agriculture and fragments of remnant cloud forest below about 1650 m elevation, and intact cloud forest extending above this point to the peak at approximately 2750 m elevation. There are three ecosystems found on Montaña de Santa Bárbara ( House et al., 2002): Bosque tropical siempreverde latifoliado montano superior, cárstica (Karstic Upper Montane Evergreen Broadleaf Forest), Bosque tropical siempreverde latifoliado altimontano, cárstica (Karstic Altimontane Evergreen Broadleaf Forest), and, above 2000 m elevation, Bosque tropical siempreverde mixto altimontano, cárstica (Karstic Altimontane Evergreen Mixed Forest). These unique ecosystems exist only on Montaña de Santa Bárbara, and are characterized by having distinctive plant communities, including endemic species, on well drained karstic soils ( House et al., 2002); the type locality of T. tycherus lies in the Karstic Upper Montane Evergreen Broadleaf Forest.

Etymology. The specific name tycherus is derived from the Greek word “tycheros,” meaning “lucky,” and is given in reference to a remarkable string of providential events that preceded the acquisition of the holotype.

Remarks. Another species of the family Typhlopidae , Ramphotyphlops braminus , has been introduced to localities throughout Mesoamerica. Typhlops tycherus is distinguished from R. braminus by having 22–22–22 scales around the body (20–20– 20 in R. braminus ), more dorsal scales between rostral and tail tip (395, versus 290–338 in New World R. braminus ), and larger maximum total length (371 mm, versus 173 mm in New World R. braminus ).

Figures

FIGURE 2. Scalation of the head of the holotype of Typhlops tycherus. A = dorsal view, B = lateral view.

FIGURE 3. Dorsal and ventral aspects of the preserved holotype of Typhlops tycherus.

FIGURE 4. Montaña de Santa Bárbara, Depto. Santa Bárbara, Honduras, seen from the community of El Cedral, 1580 m elevation, in the vicinity of the type locality of Typhlops tycherus. The highest part of the mountain is>2700 m elevation. Photographed 28 January 2008 by JHT.