Tantilla carolina, Palacios-Aguilar & Fucsko & Jiménez-Arcos & Wilson & Mata-Silva, 2022

Palacios-Aguilar, Ricardo, Fucsko, Lydia Allison, Jiménez-Arcos, Víctor H., Wilson, Larry David & Mata-Silva, Vicente, 2022, Out of the Past: A new species of Tantilla of the calamarina group (Squamata: Colubridae) from southeastern coastal Guerrero, Mexico, with comments on relationships among members of the group, Amphibian & Reptile Conservation (e 320) 16 (2), pp. 120-132 : 121-125

Tantilla carolina , new species

Figs. 1–2 .

Suggested common name. Carolina’s Little Snake.

urn:lsid:zoobank.org:act:B8520FC0-94E1-4A6F-8312-F6D3EA3434EF

Holotype. BMNH 1906.6 .1.241, an apparent subadult or juvenile female from Tezonapan (= Tecoanapa), north of Ayutla , Guerrero, Mexico, collected by Hans Gadow in 1904.

Diagnosis. Tantilla carolina is a member of the T. calamarina group (Table 1). This species differs from Tantilla calamarina by the presence of more ventrals in females (156 versus [hereinafter = vs.] 118–140), more total segmental scales (194 vs. 146–179), a normallysized preocular scale in contact with the postnasal scale (vs. a preocular with a tendency toward a decrease in size to complete the loss of the scale), two postocular scales (vs. one), seven supralabials (vs. usually six), a uniform dorsal head color followed by two pale postparietal spots (vs. a head pattern consisting of a spatulate dark anterior extension of the middorsal dark stripe flanked by prominent pale narrow longitudinal markings confluent with the pale postparietal spots), and a body pattern involving a dark lateral stripe that does not extend to the end of the body (vs. a dark brown lateral stripe on rows 3 and 4 extending the length of the body). The new species differs from Tantilla cascadae by the presence of more ventrals in females (156 vs. 139–144), more total segmental scales (194 vs. 176–192), seven supralabial scales (vs. six), and the dorsum of the head without a pattern but containing a pair of small pale postparietal spots (vs. a spatulate dark anterior extension of the middorsal dark stripe flanked by pale narrow longitudinal markings confluent with pale postparietal spots, or narrowly separated from the pale postparietal spots). The new species differs from Tantilla ceboruca by lacking a pattern and a pair of small pale postparietal scales on the dorsum of the head (vs. a spatulate extension of the middorsal dark stripe flanked by pale longitudinal markings confluent with postparietal spots and extending anteriorly along the sides of the parietal scales and across the supraoculars and prefrontals to join on the internasals), and a lateral portion of the head without a pattern (vs. one having each supralabial with a white border). The new species differs from Tantilla coronadoi by the presence of fewer ventral scales (156 vs. 165– 178), fewer subcaudal scales (38 vs. 40–41), fewer total segmental scales (194 vs. 205–219), the anterior and posterior temporals in contact with one another (vs. those two scales separated from one another by contact of the 7 th supralabial and the parietal scale), and the dorsal and lateral portions of the head lacking a pattern (vs. a dorsal head pattern consisting of a spatulate dark anterior extension of the middorsal dark stripe flanked by pale anterior extensions of the dorsolateral ground color, and a lateral head pattern consisting of supralabials with dark upper and pale lower portions). The new species differs from Tantilla deppei by the presence of fewer subcaudal scales (38 vs. 43–50), fewer total segmental scales (194 vs. 196–214), and the dorsal and lateral portions of the head lack a pattern and a pair of small pale postparietal spots (vs. a spatulate dark anterior extension of the middorsal dark stripe flanked by pale anterior extensions of a middorsally-divided pale nuchal band). The new species differs from Tantilla sertula by the presence of fewer ventrals in females (156 vs.161), more subcaudals in females (38 vs. 30), more total segmental scales (194 vs. 191), and the dorsal and lateral portions of the head lack a pattern (vs. a dorsal head pattern consisting of a spatulate dark anterior extension of the middorsal dark stripe flanked by prominent pale, narrow, longitudinal markings confluent with pale postparietal spots). The new species differs from Tantilla vermiformis by the presence of more ventral scales in females (156 vs. 120–129), more subcaudal scales (38 vs. 19–24), more total segmental scales (194 vs. 140–150), as well as by the presence of a small pair of pale postparietal spots confined to single scales (vs. a single pale spot crossing both parietal scales).

Description of the holotype ( Figs. 1–2 ). An apparent subadult or juvenile female with 15 smooth dorsal scales throughout the trunk, 156 ventrals, a divided cloacal scute (= anal plate), 38 subcaudals, a total length of 112 mm, a tail length of 14 mm, and a tail/total length ratio of 0.125.

Nasal completely divided, posterior section in broad contact with a single preocular on both sides of head; two postoculars, approximately subequal in size; one anterior and one posterior temporal, in contact with one another, anterior temporal separating supralabials five, six, and seven from parietal, posterior temporal shorter than anterior temporal, approximately the shape of a dorsal body scale, although somewhat larger; supralabials 7–7, the 1 st in contact with rostral, prenasal, postnasal, and 2 nd supralabial, the 2 nd with postnasal, preocular, and 3 rd supralabial, the 3 rd with preocular, orbit, and 4 th supralabial, the 4 th with orbit, lower postocular, and 5 th supralabial, the 5 th with lower postocular, anterior temporal, and 6 th supralabial, the 6 th with 5 th supralabial, anterior temporal, and 7 th supralabial, the 7 th with the 6 th Table 1. Comparison of selected morphological features among the eight members of the Tantilla calamarina group. Data summarized from Wilson and Campbell (2000); Savage (2002); Canseco-Márquez et al. (2007); Wilson and Mata-Silva (2014); Cruz-Sáenz et al. (2015); Rocha et al. (2016); and Palacios-Aguilar et al. (2021).

Table 1 Continued. Comparison of selected morphological features among the eight members of the Tantilla calamarina group. Data summarized from Wilson and Campbell (2000); Savage (2002); Canseco-Márquez et al. (2007); Wilson and Mata-Silva (2014); Cruz-Sáenz et al. (2015); Rocha et al. (2016); and Palacios-Aguilar et al. (2021).

supralabial, anterior and posterior temporals, and two post-cephalic scales, with the 7 th the largest; infralabials 6–6, with the 1 st pair separated by contact of mental and anterior chinshields, the first four in contact with anterior chin shields, with the 4 th largest; and anterior chinshields larger than posterior pair.

In preservative, the dorsal and lateral portions of the head are uniform dark brown, without a pattern ( Fig. 1 ). A pair of pale postparietal spots, pale yellow in color, are present on the single scales located at the juncture of the parietal and posterior temporal scales, one each on either side of the head ( Fig. 1 ). The dorsal ground color in preservative is brown with a dark brown middorsal stripe confined to the middorsal scale row, which extends to the end of the tail, breaking up into isolated dark spots, one per scale on the posterior region of the body and tail ( Fig. 2 ). The remainder of the dorsum lacks a pattern. The venter is a uniform (perhaps cream) color in preservative.

Distribution. Known only from the type locality (Fig. 3). Tecoanapa is the seat of the municipality of Tecoanapa in the Pacific lowlands of southeastern Guerrero (coordinates 16°53’N, 99°24’W). Tecoanapa is a city located on Mexico Highway 95, east-northeast of Acapulco and south-southeast of Chilpancingo. The town lies at an elevation of 431 m (http:// PueblosAmerica.com; accessed 30 March 2022). The vegetation in the region consists of a mixture of tropical deciduous forest (selva baja caducifolia), oak forest (bosque de encino), and agricultural lands, according to the available maps (CONABIO 1999).

Conservation assessment. The Environmental Vulnerability Score (EVS) for Tantilla carolina can be calculated as 6 + 8 + 2 = 16, which places its score in the middle of the high vulnerability category, as explained by Wilson et al. (2013).

Etymology. We are privileged to name this small snake in honor of the Hungarian Freedom Fighter Karolina Laszló (Fig. 4), in recognition of her dedication to the maintenance of human rights for all peoples in the face of totalitarianism, beginning with the Hungarian Revolution in 1956. As a young woman, Karolina was forced to join the exodus of her country people, in the company of her new husband, a soldier, Ede Károly Fucskó, who bravely defied the Hungarian dictatorship, communism, and the invading Soviet army. Ede Károly Udvarhelyi was adopted at an early age, when his mother remarried and thus kept the surname Fucskó. As the couple roamed through several European countries, in search of a refuge from the terror of oppressive political regimes, they escaped to England before seeking asylum in Australia. Due to unforeseen circumstances, however, the family of Fig. 3. Geographic distribution of the Tantilla calamarina group species in western Mexico. The black star represents the type locality of Tantilla carolina sp. nov. described herein.

Figures

Fig. 1. Dorsal (A), lateral (B), and ventral (C) views of the head of the holotype of Tantilla carolina sp. nov. (BMNH 1906.6.1.241).

Fig. 2. Dorsal view of the holotype of Tantilla carolina sp. nov. (BMNH 1906.6.1.241).