Tantilla aff. melanocephala Ghizoni et al. (2009)

dos Santos Azevedo, Weverton, Franco, Francisco Luís, Menezes, Lucas, Kunz, Tobias Saraiva & Grazziotin, Felipe Gobbi, 2024, Integrated evidence sheds light on the taxonomy of the widespread Tantilla melanocephala species complex (Serpentes: Colubridae) and indicates the existence of a new species from southern South America, Organisms Diversity & Evolution (New York, N. Y.) 24 (1), pp. 119-147 : 129-137

Tantilla aff. melanocephala Ghizoni et al. (2009)

Holotype and type locality Holotype and type locality An adult male ( Figs. 7 , 10a ), IBSP 92724 (field number of project “ Scales of Biodiversity ,” SB 1957), collected by Ivo R. Ghizoni-Junior on 11 February 2021, in the municipality of Lages (28° 15′ 45.8″ S, 50° 26′ 05.0″ W; approx. 1032 m above sea level), state of Santa Catarina, southern Brazil ( Fig. 6 ) .

Paratypes (Table S 6, supplementary tables). Fifteen specimens (six males and nine females) from southern Brazil: (1) an adult female, IBSP 91713 , collected by L. M. Borges on 17 June 2019, in the municipality of Bagé (Rincão do Inferno) (30° 54′ S, 53° 41′ W), state of Rio Grande do Sul; (2) an adult male, IBSP 91838 , collected by C. M. Rosa on 15 September de 2019, in the municipality of Jari ( Linha Nova ) (29° 22′ S, 54° 17′ W), state of Rio Grande do Sul; (3) an adult male, ZUFSM 3923 , collected by M. S. Conceição on 04 April 2012, in the municipality of São Vicente do Sul ( São Rafael ) (29° 48′ S, 54° 45′ W), state of Rio Grande do Sul ; (4) an adult female, ZUFSM 3180 , collected by S. Alves on 29 October 2012, in the municipality of São Gabriel ( Cerro do Batovi ) (30° 34′ S, 54° 29′ W), state of Rio Grande do Sul ; (5) an adult female, ZUFSM 2040 , collected by C. M. Rosa on 12 August 2017, in the municipality of Rosário do Sul ( Serra do Caverá ) (30° 21′ S, 55° 15′ W), state of Rio Grande do Sul ; (6) an adult female, ZUFSM 0732 , collected by I. Lopes on 15 January 1994, in the municipality of Caçapava do Sul (30° 30′ S, 53° 29′ W), state of Rio Grande do Sul ; (7) an adult female, IBSP 91865 , collected by G. M. Pontes on 25 September 2019, in the municipality of São Jerônimo (29° 58′ S, 51° 43′ W), state of Rio Grande do Sul ; (8) an adult male, IBSP 89878 , collected by R. Balestrin on 29 August 2017, in the municipality of São Jerônimo (29° 57′ S, 51° 43′ W), state of Rio Grande do Sul ; (9) a juvenile male, IBSP 92725 , collected by I. R. Ghizoni-Junior on 11 February 2021 in the municipality of Lages (28° 4′ S 50° 5′ W), state of Santa Catarina ; (10) an adult female, IBSP 92723 , collected by I. R. Ghizoni-Junior on 12 February 2021, in the municipality of painel (28° 16′ S 50° 26′ W), state of Santa Catarina ; (11) an adult female, CHUFSC 1165 , collected by A. Regolin and C. Salvador on 14 April 2009, in the municipality of Capão Alto (28° 8′ S 50° 41′ W), state of Santa Catarina ; (12) an adult male, CHUFSC 1002 , collected by T. S. Kunz on 20 March 2008, in the municipality of Painel (28° 4′ S, 50° 5′ W), state of Santa Catarina; (13) an adult female, IBSP 27560 , collected by C. Dyskska on 16 September 1967, in the municipality of Curitiba (Boqueirão) (25° 30′ S, 49° 14′ W), state of Paraná; (14) an adult female, IBSP 76633 , collected by F. L. Franco on 2004, in the municipality of Capitão Leônidas Marques (25° 29′ S, 53° 35′ W), state of Paraná; (15) an adult male, IBSP 76644 , collected by F. L. Franco on 2004, in the municipality of Capitão Leônidas Marques (25° 29′ S, 53° 36′ W), state of Paraná .

Other specimens examined (Table S6, supplementary tables). Fourteen specimens (five males and nine females) from southern Brazil. State of Rio Grande do Sul: (1) An adult female, IBSP 89626 , municipality of São Jerônimo ; (2) a juvenile male, IBSP 91845 , municipality of São Jerônimo ; (3) a juvenile female, IBSP 91846 , municipality of São Jerônimo ; (4) a juvenile male, IBSP 91644 , municipality of Bagé ( Rincão do Inferno ); (5) an adult female, ZUFSM 3924 , municipality of São Vicente do Sul ( São Rafael ); (6) an adult female, ZUFSM 3177 , municipality of São Gabriel ( Cerro do Batovi ); (7) an adult female, IBSP 45923 , municipality of Porto Alegre ; (8) an adult male, IBSP 90139 , municipality of Rosário do Sul ( Serra do Caverá ). State of Santa Catarina : (9) an adult male, IBSP 18368 , municipality of Lages ; (10) an adult female, CHUFSC 1001 , municipality of Painel. State of Paraná : (11) an adult female, IBSP 3251 , municipality of Cachoeirinha ; (12) an adult female, IBSP 10203 , municipality of Palmeira ; (13) an adult female, IBSP 17223 , municipality of Lapa ; (14) an adult male, IBSP 17841 , municipality of Jaguariaíva .

Etymology The specific epithet is treated as a feminine singular genitive in honor of Dr. Selma Maria de Almeida-Santos for her invaluable contribution to the knowledge of reproductive biology of Brazilian snakes and lizards. Besides her outstanding impact in the field, Dr. Almeida-Santos has mentored dozens of students and she is known by her distinctive welcoming manner. Therefore, in the specific epithet, we allude to her unique personality by joining her name with the word mother in Portuguese: “ Selma ”+ “ mãe ” = selmae .

for the number of ventral and subcaudal scales presented separately for each sex,

comparing Tantilla selmae sp.

nov. with other operational taxonomic units (OTUs)

from the T. melanocephala complex, based on dataset D1.

Abbreviations: n, number of analyzed individuals; r, range;

x, mean; s, standard deviation;

m, median Diagnosis Tantilla selmae is diagnosed and distinguished from the South America species of Tantilla by the unique combination of the following morphological characters: (1) 15–15-15 dorsal scales; (2) supralabials seven, 3rd–4th in contact with orbit; (3) infralabials six, 1st–4th in contact with anterior genials; (4) preocular one; (5) postocular two; (6) temporals 1 + 1; (7) ventrals 128–150 (128–145 in males, 139–150 in females); (8) subcaudals 42–58 (48–58 in males, 42–50 in females); (9) cephalic cap wide and black; (10) lateral extension of the cephalic cap through the temporal region always present (usually extends to the labial border between 6 and 7th supralabials, sometimes does not reach the labial border); (11) lateral extension of the cephalic cap to the subocular region always present; (12) black collar on the neck that extends longitudinally in the vertebral row through four scales (rarely three scales and sometimes five), followed by a pale and discreet collar, more evident laterally; (13) longitudinal connection between cephalic cap and neck collar always present; (14) orange-brown dorsal background color; (15) black vertebral longitudinal line, usually present and dashed, sometimes linear, ranging from evident to vestigial; (16) black vertebral longitudinal line in the tail always present and linear, ranging from evident to vestigial; (17) black diffuse lateral stripe, that extends longitudinally, and varies from evident to vestigial (is denser posteriorly in the trunk and generally occupies the first three rows of dorsal scales and reaches a part of the 4th row); (18) venter color is always cream, with macules only at the lateral edges of the ventrals; (19) bare area on the left side of the asulcate surface of the hemipenial body.

Comparisons Tantilla selmae ( Fig. 8a ) is distinguished from the Tantilla species of the melanocephala complex by presenting a bicolored dorsal pattern, with a black diffuse lateral stripe along the body, which gradually diffuses towards the middorsal row in an orange-brown background color (versus dorsum without stripes, with reddish orange background color in T. boipiranga ) ( Fig. 8b ) and for presenting a low degree of color variation (versus general pattern of highly variable color in T. melanocephala ) ( Fig. 8c ) ( Sawaya & Sazima, 2003; Wilson & Mena, 1980). In addition, new species exhibits a lower number of ventral and subcaudal scales compared to the other species of the melanocephala complex ( Fig. 4 ; Table 1). Tantilla selmae ( Fig. 8a ) is easily distinguished from the other South America Tantilla species as follows characteristics: T. selmae ( Fig. 8a ) has a dorsum of orange-brown background color, with a diffuse lateral stripe along the body (versus dorsum with background color ranging from red–orange to dark red and a black tip present on each dorsal scale in T. capistrata [ Fig. 8d ], and dorsum pale grayish-tan background color in T. petersi [ Fig. 8e ]) ( Wilson, 1979; Wilson & Mata-Silva, 2015); the venter of T. selmae is uniform cream colored, with macules only on the lateral edges of ventral scales (versus venter ranging from cream to bright coral red in T. alticola [ Fig. 9a ] and a venter with a narrow and irregular median dark line, confluent with a narrow irregular edging of dark pigment along the anterior portion of each ventral scale in T. miyatai [ Fig. 9b ]) ( Wilson, 1986, 1987, 1990); T. selmae can be promptly distinguished from T. nigra ( Fig. 9c ) due to its bicolored dorsum pattern, distinct from the cream color of the venter (versus dorsum and venter color totally black and presence of two yellowish pale nuchal bands) ( Wilson, 1992); T. selmae has no lateral line along the body (versus dorsal pattern with multiple faint dark longitudinal lines, and a cream venter with a single brown spot on the lateral edges of each ventral in T. insulamontana [ Fig. 9d ]) ( Arteaga, 2021a; Wilson & Mena, 1980); T. selmae also has the black and wide cephalic cap, which differs from the T. andinista ( Fig. 9e ), which has a reduced dark brown cephalic cap ( Wilson & Mena, 1980); and finally, T. selmae is distinguished from T. semicincta , T. supracincta , and T. tjiasmantoi , by the absence of transverse bands along the body, present in these three species ( Fig. 9f, g, h ). Moreover, T. semicincta has a white venter and can also exhibit a striped dorsal pattern or an intermediate pattern between transverse bands and longitudinal stripes ( Wilson, 1976). Whereas T. supracincta has a venter bright red, with macules only on the lateral edges, which are a continuation of the transverse dorsal bands ( Fig. 9g ) ( Arteaga, 2021b). While T. tjiasmantoi has a sexually dimorphic ventral pattern, with females may have a venter with dark dotted outlines in some parts, and males having irregular bands that sometimes form complete rings around the body or create a checkerboard pattern of black and cream squares ( Fig. 9h ) ( Koch & Venegas, 2016).

Description of the holotype IBSP 92724 The specimen is an adult male. The last body weight in life was 4.7 g. The total length is 278 mm, of which 218 mm is snout-vent length and 60 mm is tail length (the terminal spine of the tail is frayed); the body is elongated and slightly flattened dorsoventrally; the dorsal region of the head is slightly flattened; head is distinguished from the body by a slight cervical constriction of 4.6 mm width; the width of the middle of the body is 6.3 mm and the cloacal region is 4.6 mm; both hemipenis are everted and dehydrated; the dorsal scales are smooth and arranged in 15–15-15 rows; it has three gulars between posterior genial and preventral on the right side of the head; it has one preventral, 136 ventrals, one divided cloacal, and 48 paired subcaudals; the head is 7.1 mm length, 5.1 mm width, and 3.1 mm height; the distance between the nostrils is 2.4 mm; the distance between the eyes is 3.7 mm; the distance from the eye at the lateral edge of the rostral is 2.2 mm; the is pupil round; the rostral 2.1 times wider than high (2.1 × 1.0 mm); it has two internasals and two prefrontals; the frontal is hexagonal, 1.5 times longer than wide (3.0 × 2.0 mm); In both sides of the head it has one preocular, two postoculars, one supraocular, one anterior and one posterior temporal, two nasals, seven supralabials, 3–4 contact the orbit, and six infralabials, 1–4 in contact with anterior genials, and 4th in contact with posterior genials; the mental is triangular, about 1.5 times wider than long (1.9 × 1.2 mm), and is separated from genials by the first pair of infralabials; it has two anterior and two posterior genials. The proportions of scales measured on the right side of the head are as follows: internasal 2.2 times wider than long (1.6 × 0.7 mm); anterior nasal 1.1 times high than long (0.9 × 0.8 mm); posterior nasal 1.4 times longer than high (0.7 × 0.5 mm); prefrontal about 1.2 times wider than long (1.7 × 1.4 mm); paired parietals 1.5 times longer than wide (3.8 × 2.4 mm); supraocular 2.1 times longer than wide (1.9 × 0.9 mm); ocular as high as long (both dimensions 1.2 mm); preocular almost as high as long (0.6 × 0.7 mm); inferior postocular is as long as high (0.6 × 0.6 mm); superior postocular is 1.6 times longer than the high (0.8 × 0.5 mm); anterior temporal is 2 times longer than wide (1.8 × 0.9 mm); posterior temporal is 1.7 times longer than wide (1.7 × 1.0 mm); anterior genial about 1.3 times longer than wide (1.5 × 1.1 mm); the posterior genial 1.6 times longer than wide (1.3 × 0.8 mm).

Coloration of holotype in preservative The specimen exhibits a dorsal background color dark orange-brown with the edges of the scales showing black spots giving a contour aspect. In the middorsal row, there are small black blotches on the anterior and posterior portions of each scale ( Fig. 7 ). There are also macules of the same color, in the center of these scales. Together, these blotches and macules form a partially dashed vertebral longitudinal line, which extend longitudinally along the body. In the tail, this line is linear. In the dorsolateral region of the body, there is a much concentration of small black spots on the scales of the first dorsal rows, mostly on the edges of these scales. These spots form a lateral stripe on each side of the body, which gradually diffuses towards the middorsal row. This diffuse lateral stripe extends to the edges of the ventrals and is denser posteriorly on the body. The ventrals and subcaudals coloration is uniform cream. The dorsal background color of the head is light brown, while laterally and posteriorly the color is cream. On the head, there is a large black cephalic cap. Dorsally, the cephalic cap extends over the entire region of the head. Anteriorly, the cephalic cap extends to the lower edge of the rostral. Laterally, the cephalic cap extends to the labial edge through the scales in contact with the eye (preoculars, supraoculars, postoculars, and supralabials), beyond nasals and temporals. The cephalic cap covers most of the temporals. It extends over most of the 2nd, 3rd, 4th, and 6th supralabials, a small part of the edges of 1st, 5th, and 7th supralabials, passes the edge of labial and reaches the infralabials. Most of the 1st supralabial and half of the 2nd supralabial are not covered by the cephalic cap. Similarly, a portion of the inferior postoculars, anterior temporals and supralabials 5th and 6th scales are not covered by the cephalic cap, forming a rounded cream colored blotch behind the eyes. In the same way, there is a second pale region between the lateral portion posterior to the cephalic cap and anterior to the neck collar, which is continuous with the cream coloration of the gular region. The gular region is slightly maculate. The mental and infralabials are heavily maculates. The cephalic cap connects to the neck collar by a longitudinal union in the region of the parietal suture. The collar on the neck is black and large, extending longitudinally over five scales in the vertebral row and laterally to the outer edges of the preventrals.

Morphological variation The analyzed specimens present a morphological characters pattern fairly conservative. The values of summary statistics for evaluated characters are described in Tables S12 and S13. The values of meristic features of sampled individuals are as follows: (1) three gulars (n = 18), sometimes four gulars (n = 5), or two gulars (n = 4); (2) one preventrals (n = 14), two preventrals (n = 12), and occasionally three preventrals (n = 4); (3) six infralabials (n = 28), rarely five (n = 2); (4) seven supralabials (n = 26), occasionally six (n = 3), and rarely five (n = 1); (5) one preoculars (n = 30); (6) two postoculars (n = 28), rarely one (n = 2); and (7) temporals 1 + 1 (n = 27), occasionally temporals 1 + 2 (n = 3). The 3rd and 4th supralabials scales are in contact with the orbit (n = 28), rarely 2nd and 3rd (n = 1) or 3rd, 4th, and 5th (n = 1). The cephalic cap extends laterally through the temporal region to the labial border, between 6 and 7th supralabials (n = 23), but sometimes does not reach the labial border (n = 7). The cephalic cap also extends laterally to the mouth, through the scales in contact with the eyes (supraocular, preocular, postocular, and supralabials), with the exception of specimens IBSP 17841, ZUFSM 3924, and CHUFSC 1002, where extends below the eyes, to half of the supralabials scales. The connection between the cephalic cap and the neck collar is present in all analyzed specimens. The collar on the neck extends longitudinally in the vertebral row through four scales (n = 25), occasionally five scales (n = 4), and rarely three scales (n = 1). The vertebral longitudinal line is evident and dashed (n = 22), vestigial (n = 7), and rarely evident and linear (n = 1). The vertebral longitudinal line in the tail is present and evident (n = 25) and vestigial (n = 5). All specimens showed a black diffuse lateral stripe, denser posteriorly in the trunk, generally occupying the first three rows of dorsal scales and reaching part of the 4th row. The diffuse lateral stripe was vestigial in the specimens IBSP 45923 and IBSP 17841. The preserved specimens exhibited a uniform cream and immaculate coloration in the gular region, with the exception of specimens IBSP 92723 and the holotype IBSP 92724, which presented black punctuated macules in this region. Likewise, all specimens were cream colored and immaculate in the ventral and subcaudal regions, with macules only at the lateral edges of the ventral and subcaudal scales. The exception was specimen IBSP 92723, which showed some black macules along the venter.

Sexual dimorphism (The abbreviations for the values described below are as follows: x = mean; s = standard deviation; m = median). Females have a longer trunk relative length and more ventral scales (x = 146.17, s = 2.81, m = 146.5, p <0.01) than males (x = 136.75, s = 4.39, m = 136.5, p <0.01). On the other hand, males have a longer relative tail length (RTL) and more subcaudal scales (x = 53.42, s = 3.23, m = 53, p <0.01) than females (x = 46.36, s = 2.34, m = 47, p <0.01). Furthermore, males have a relative head length (RHL) longer than females (p = 0.01) (see Table S 14 in supplementary tables).

Coloration in life Although the general color pattern in the live specimens has been highly conservative, some variations were found ( Fig. 10 ). The background color of the head is pale, ranging from cream to slightly orange. The cephalic cap and collar on the neck are black, as are the vertebral longitudinal line and diffuse lateral stripe. Posterior to collar on the neck, there is a discreet pale band, more evident laterally. The species showed an orange-brown dorsal background color and uniform cream venter, with light orange and dark color macules on the lateral edges of the ventrals. The vertebral longitudinal line is evident and linear ( Fig. 10a, b, c ), dashed ( Fig. 10d, f ), and vestigial ( Fig. 10e ). Likewise, the diffuse lateral stripe is evident ( Fig. 10a, b, c ), poorly evident ( Fig. 10d ), and vestigial ( Fig. 10e, f ).

Hemipenis morphology The fully everted and maximally expanded hemipenis is unilobed, unicalyculate, and noncapitate ( Fig. 11 ). The proximal region of the hemipenial body is predominantly nude, with some spinules irregularly distributed. This region is also ornamented with a distinct spine on the asulcate surface and two large spines on the limits between the sulcate and lateral surfaces. These two spines present different sizes; the most proximal is usually larger than the other. The distal region of the hemipenial body is ornamented with large and spaced spines, which are arranged in transverse rows on the sulcate surface. Furthermore, there is also a bare area on the left side of the asulcate surface this region. The sulcus spermaticus is simple, centrolinearly oriented, extending from the base of the hemipenis to the apex of the lobe, bordered by spinules throughout its extension. The lobe is ornamented with calyces only in asulcate and lateral surfaces. The calyces are formed by a series of spinules that are gradually arranged in transverse rows on the sulcate surface of the lobe. These spinules invade a small part of the most distal region of the hemipenial body on the asulcate surface.

Figures

Fig. 7 Holotype of Tantilla selmae (IBSP 92724). Head views on the (a) dorsal, (b) right lateral, (c) left lateral, and (d) ventral. Body views on the (e) dorsal and (f) ventral. Horizontal scale bar: 2 mm. Vertical scale bar: 10 mm

Fig.10 Specimens of Tantilla selmae in life. a Adult male from Lages, SC, Brazil *IBSP 92724; b adult male from Jari, RS, Brazil **IBSP 91838; c adult female from Capão Alto, SC, Brazil **CHUFSC 1165; d adult female from Bagé, RS, Brazil **IBSP91713; e adult from

Fig.6 Geographical distribu- tion of taxa corresponding to the individuals examined in this study. Stars correspond to types localities of valid species; circles represent the distribution of analyzed indi- viduals; triangles correspond to sequenced samples; crosses and question marks symbolize the type localities of the synonyms of T. melanocephala species; the question marks represent the approximate type locality according to Wilson and Mena (1980). The brown dashed polygon represents the known distribution of the T. melano- cephala complex according to Nogueira et al. (2019); the other non-dashed polygons represent the distribution of evolutionary units recognized within the T. melanocephala complex. Acro- nyms of the Brazilian states: AM, Amazonas; PA, Pará; PB, Paraíba; PE, Pernambuco; MT, Mato Grosso; MG, Minas Ger- ais; SP, São Paulo; PR, Paraná; SC, Santa Catarina; RS, Rio Grande do Sul

Fig. 8 Overview of South American Tantilla species. a T. selmae; b T. boipiranga; c T. melanocephala, Surinam pat- tern (above), Brazilian Cerrado pattern (middle), and trans- Andean pattern (bellow); d T. capistrata; e T. petersi. Illustra- tions by Lucas Kias

Fig. 4 Boxplots for selected variables based on the dataset D1, demonstrating the morpho- logical differences among OTUs of the Tantilla melanocephala complex. Number of ventral scales in (a) females and (b) males; number of subcaudal scales in (c) females and (d) males. The thin (red) horizontal line within the box indicates the mean; the thick (black) horizon- tal line within the box indicates the median; the open circles are data points

Fig. 9 Overview of South American Tantilla species. a T. alticola Colombian pattern; b T. miyatai; c T. nigra; d T. insulamontana; e T. andinista; f T. semicincta; g T. supracincta; h T. tjiasmantoi. Illustrations by Lucas Kias

Fig.11 Hemipenis of Tantilla selmae (IBSP 91838). Asulcate (a), lateral (b), and sulcate (c) views. Vertical scale bar: 2 mm