Tantilla psittaca, Mccranie, James R., 2011

Mccranie, James R., 2011, A new species of Tantilla of the taeniata species group (Reptilia, Squamata, Colubridae, Colubrinae) from northeastern Honduras, Zootaxa 3037, pp. 37-44 : 38-42

Tantilla psittaca sp. nov.

Figures 1–3

Tantilla taeniata: Wilson & Meyer 1971: 32 (part); Wilson 1982: 56 (part); Wilson & Meyer 1982: 109 (part); Wilson 1983: 344.1 (part); Wilson & Meyer 1985: 103 (part); Wilson & McCranie 1999: 328 (part); McCranie et al. 2002: 28; McCranie et al. 2006: 179 (part); McCranie 2011: 227 (part).

Holotype. USNM 578389, an adult male from Rawa Kiamp (15°06’N, 84°26’W, 60 m) along Río Siksatingni, department of Gracias a Dios, Honduras, collected 15 July 2008 by James R. McCranie.

Paratypes (6). Honduras, department of Gracias a Dios: USNM 559707, 570459, 578390 from Rus Rus (14°43’N, 84°27’W, 60 m), LSUMZ 21770 from Tánsin (15°18’N, 83°53’W, 5 m), SMF 86170 from Río Cuyamel (15°34’N, 84°59’W, 200 m); department of Colón: SMF 86171 from El Ocotillal (15°22’N, 85°13’W, 420 m).

Diagnosis. Tantilla psittaca can be distinguished from T. taeniata (herein restricted to the Guatemalan populations discussed by Campbell 1998; see Discussion below) by having 153–163 ventrals in males (143–152 ventrals in male T. taeniata ; Campbell did not study any females). Six other named species of Tantilla assigned to the T. taeniata species group have been reported from Guatemala and southern Belize ( T. cuniculator , T. hendersoni , T. impensa , T. jani , T. tecta , and T. vulcani ). Tantilla psittaca differs from all of those species in having the middorsal pale stripe complete and involving all of the vertebral scale row and the adjacent one-third to one-half of the paravertebral scale rows (versus middorsal stripe absent or faintly indicated only on anterior body in T. cuniculator , middorsal stripe confined to vertebral scale row and narrowly interrupted in T. hendersoni , middorsal stripe confined to vertebral scale row in T. impensa , middorsal stripe absent or reduced to series of small spots on vertebral row in T. jani , middorsal stripe confined to median third of vertebral scale row in T. tecta , and middorsal stripe reduced to series of spots on vertebral row in T. vulcani ). Two named species of the T. taeniata species group are known to occur in Honduras ( T. impensa [discussed above] and T. tritaeniata ). Tantilla psittaca can be distinguished from T. tritaeniata in having the pale middorsal stripe narrowing anteriorly and beginning on the fourth or fifth scale row posterior to the parietals (versus pale middorsal stripe not narrowing anteriorly and beginning on third scale row posterior to parietals in T. tritaeniata ) and in having red ventral surfaces in life, at least on the posterior third of the body and all of subcaudal surface (versus yellow ventral surfaces in life in T. tritaeniata ). Another named species of the T. taeniata species group, T. reticulata , has been reported from Nicaragua to Panama. Tantilla psittaca differs from T. reticulata in having red ventral surfaces in life and in lacking darker pigment on the anterior portion of many lateral dorsal scales (versus ventral surfaces yellow in life and darker pigment present anteriorly on many lateral dorsal scales in T. reticulata ). In addition, five of the seven T. psittaca have a complete nuchal collar, whereas T. reticulata always has dark pigment broadly interrupted the nuchal collar medially.

Description of holotype. An adult male; TL 354 mm; SVL 268 mm; TAL 86 mm (24.3% of TL); HL 6.7 mm from front face of rostral to posterior end of mandible; HW 4.2 mm at broadest point (level of angle of mouth); head barely distinct from neck; snout broadly rounded in dorsal view; eye length 1.1 mm; snout length 2.8 mm, about 2.5 times as long as eye; pupil circular; rostral about 1.5 times wider than high (1.1 mm x 0.6 mm); internasal length about one-half of width (0.6 mm x 1.3 mm); prefrontal much larger than internasal, slightly wider than long (1.3 mm x 1.1 mm); median prefrontal suture 0.9 mm, about one-third times as long as frontal; frontal with slight anterior extension, V-shaped posteriorly, about 1.4 times longer than wide (2.8 mm x 2.0 mm), nearly twice as long as distance from its anterior edge to tip of snout (1.5 mm); parietal about 1.9 times longer than wide (3.8 mm x 2.0 mm), median suture 1.7 mm, about 61% length of frontal; parietals contacting seven nuchal scales; supraocular longer than wide (1.4 mm x 0.8 mm), bordering orbit, contacting parietal, upper postocular, preocular, prefrontal, and internasal.

Nasal divided, anterior nasal contacting rostral, internasal, and first supralabial, posterior nasal contacting internasal, prefrontal, preocular, and first and second supralabials, nostril located in center portion of nasal (part of division of nasal); loreal absent; preoculars 1–1, preocular higher than long (0.6 mm x 0.3 mm), lower edge contacting second and third supralabials; postoculars 2–2, upper slightly larger than lower (height 0.6 mm x 0.5 mm); temporals 1+1, anterior temporal 1.4 times longer than high (1.3 mm x 0.9 mm), posterior temporal 2.8 times longer than high (1.7 mm x 0.6 mm); supralabials 7–7, third and fourth bordering orbit, fourth and fifth contacting lower postocular, fifth also contacting anterior temporal, sixth contacting anterior temporal, seventh contacting anterior and posterior temporals; mental 1.6 times wider than long (1.0 mm x 0.6 mm), contacting anterior pair of chinshields; anterior chinshields 2.6 times longer than wide (1.8 mm x 0.7 mm), not extending laterally to border of lip; posterior pair of chinshields 1.8 times longer than wide (0.7 mm x 0.4 mm), separated from first ventral by two gular scales and two preventral scales; infralabials 7–7, first four contacting anterior pair of chinshields; dorsal scales in 15–15–15 transverse rows, smooth throughout, lacking apical pits and supracloacal tubercles; dorsal scales in six rows at level of tenth subcaudal; ventrals 161; cloacal scute divided; subcaudals 70, paired; ventrals plus subcaudals 231; tail tip slightly pointed.

Maxillary teeth number 17–16 (right-left sides, respectively); all teeth of equal length; diastema present; two teeth present posterior to diastema.

Color in life: Dorsal ground color Fuscous (21); middorsal stripe Clay Color (26) with Sepia (219) edges; dorsolateral stripe Light Drab (119C) with Sepia (219) edges; all pale stripes on dorsal surface of tail same color as those of body, except with reddish tinge; nuchal collar Pale Horn Color (92) with scales outlined with brown; postocular spot Pale Horn Color; spot anterior to eye Pale Horn Color with brownish tinge; subocular spot and spot on ultimate supralabial Sepia (219); ventral surface of head cream, changing to cream with reddish tinge on throat; venter of body Peach Red (94) on anterior third, grading to Ferruginous (41) at midbody and continuing onto subcaudal surface to tip of tail; iris Sepia (119).

Color in alcohol: Dorsal surfaces brown with pale brown nuchal collar and pale brown middorsal and lateral stripes; pale middorsal stripe occupying vertebral row and adjacent half of paravertebral rows, bounded on both sides by dark brown continuous stripe on ventrolateral half of paravertebral rows; pale middorsal stripe narrows anteriorly on first scale involved in stripe; pale middorsal stripe extending well onto tail; pale middorsal stripe beginning on fifth scale posterior to parietals; pale lateral stripe present on adjacent halves of scale rows 3–4, bounded above and below by continuous dark brown stripe on other halves of scale rows 3–4; pale lateral stripe extending well onto tail; pale lateral stripe beginning on fifth scale posterior to ultimate supralabial; lower twothirds of scale row 1 cream, area of scale row 1 with pale pigment slightly decreasing posteriorly on body; pale nuchal collar complete, involving posterior tips of parietals plus one and one-third scale rows dorsally, pale nuchal collar also involving posterior half of ultimate supralabial plus one and three-quarters scale rows laterally; dorsal surface of head pale brown; cream spot involving postnasal and supralabials 1–2; another, larger cream spot involving lower postocular, adjacent three-quarters of anterior temporal, all of supralabial 5, and anterior and posterior portions of supralabials 4 and 6, respectively; dark pigment on supralabials 6–7 narrowing dorsally to narrowly contact dark head cap ( Figure 3 ); mental and first infralabials with brown spots, remainder of ventral surface of head cream; ventral surface of body cream on anterior third, middle third pale brown, becoming pale brown with pinkish tinge on posterior third; subcaudal surface pinkish brown, except upper tips of subcaudal scales dark brown.

Hemipenes: Partially everted organ five subcaudal scales long, single, symmetrical, semicapitate; sulcus spermaticus simple, semicentripetal, apparently extending nearly to tip of organ; pedicel naked; truncus with basal hooks and numerous smaller spines above basal hooks; apical region calyculate with spinose edges.

Variation in paratypes. Three males (2 adults, 1 subadult; LSUMZ 21770, SMF 86171, USNM 570459): TL 245–413 (320.0±85.4) mm; SVL 186–312 (241.3±64.4) mm; TAL 24.1–25.2% of TL; ventrals 153–163 (158.0±5.0); subcaudals 63–73 (69.0±5.3); ventrals plus subcaudals 216–234 (227.0±9.6). Three adult females (SMF 86170, USNM 559707, 578390): tail incomplete in all; SVL 255–292 (270.7±19.1) mm; ventrals 154–161 (158.0±3.6). All paratypes have 7–7 supralabials and 6–7 infralabials, except one side is aberrant in SMF 86170 (only 4 supralabials and 4 infralabials).

Color pattern in alcohol in the paratypes is similar to that of the holotype, except for the following slight variations. The pale middorsal stripe narrows anteriorly on the first six or seven scales involved in the stripe in LSUMZ 21770 and USNM 559707 and begins on the fourth scale row posterior to the parietals in SMF 86171 and USNM 559707. The pale middorsal stripe involves the vertebral row and only the adjacent one-third of the paravertebral rows in SMF 86170–71 and USNM 578390. The pale nuchal collar is incomplete in LSUMZ 21770 and SMF 86171, being divided by dark brown on the median scale row. The dark pigment on supralabials 6–7 narrows dorsally and does not contact the dark head cap in USNM 570459, 578390, or does not narrow dorsally and broadly contacts the dark head cap in SMF 86170–71 and USNM 559707.

Wilson and Meyer (1971:33–34) described color in life of a subadult male paratype (LSUMZ 21770): “The dorsal ground color is brown. The middorsal light stripe is gold and occupies the middorsal scale row and adjacent halves of the paravertebral rows. The lateral light stripe is gold and occupies the adjacent halves of scale rows 3 and 4. Each light stripe is outlined on both sides by a dark brown stripe occupying one-half of one scale in each case (A dark stripe, therefore is present on the lower half of scale row 3, upper half of scale row 4, and the lower half of scale row 7.), and both light stripes extend to the end of the tail. In addition, a dark brown stripe is present on the upper half of scale row 1; the lower half is reddish orange. The venter is also reddish orange except for the cream on the neck region. The head is dark brown above. The rostral is yellow with a brown central blotch. Most of the nasal scale, all of the first supralabial, the anterior two-thirds of the second supralabial, and the anteroventral corner of the third supralabial are yellow. A yellow postocular spot occupies the posterior one-half of the fourth supralabial, all of the fifth, the anterior one-half of the seventh, the lower postocular, and the anterolateral corner of the anterior temporal. The collar is yellow and is divided medially by dark brown pigment occupying one dorsal scale. The collar expands laterally to cover the last supralabial and is about one to one and one-half scales wide. The chin is cream with brown pigment present on the posterior border of the third infralabial and the medial portion of the fourth infralabial.”

The hemipenes of a paratype (SMF 86171) are nearly fully everted and are seven subcaudal scales long. The sulcus spermaticus in this specimen extends nearly to the tip of each organ. Otherwise, the hemipenes of SMF 86171 are similar to those of the holotype.

Distribution and habitat. The holotype of Tantilla psittaca (USNM 578389) was found by raking through leaf litter at the base of a tree buttress in primary broadleaf rainforest during July. Upon discovery, the snake moved rapidly into adjacent leaf litter in an attempt to escape. Three others (USNM 559707, 570459, 578390) were crawling on the ground during the day in open pine savanna during August, October, and November. The Tánsin specimen (LSUMZ 21770) was beneath a pine tree stump in pine savanna during July. The two SMF specimens were taken in broadleaf rainforest during July. Both the broadleaf rainforest and pine savanna areas are technically in the Lowland Moist Forest formation of Holdridge (1967), but differ dramatically from each other (see McCranie 2011 for a discussion of the Lowland Moist Forest formation in Honduras). Tantilla psittaca is known from 5 m to 420 m elevation.

The pine savannas where Tantilla psittaca has been found are burned annually during the driest parts of the year. Thus, cover objects such as logs and tree stumps are difficult to find in many areas, and are usually fire scarred and dry when encountered. On the other hand, extensive broadleaf rainforest still occurs in the Mosquitia, but is under increasing attack by the expanding human population, largely by people immigrating to the area from other parts of Honduras (see McCranie 2011). Thus, T. psittaca likely retains healthy populations in parts of its range, but is threatened by increased deforestation, even in the Río Plátano Biosphere Reserve. Tantilla psittaca is classified as Vulnerable using the IUCN categories and criteria (B2ab[iii])

Etymology. The name psittaca is from the Latin psittacus and means parrot. The name alludes to the type locality Rawa (also sometimes spelled Rauha) Kiamp, which translates from the native language Miskito to Parrot Camp in English.

Figures

FIGURE 1. Holotype of Tantilla psittaca (USNM 578389) in life.

FIGURE 2. Ventral surface of the holotype of Tantilla psittaca (USNM 578389) while sedated.

FIGURE 3. Lateral side of the head of the holotype of Tantilla psittaca (USNM 578389) showing the dark pigment on supralabials 6 – 7 narrowing dorsally and narrowly contacting the dark head cap.