Chironius brazili, Hamdan, Breno & Fernandes, Daniel S., 2015

Hamdan, Breno & Fernandes, Daniel S., 2015, Taxonomic revision of Chironius flavolineatus (Jan, 1863) with description of a new species (Serpentes: Colubridae), Zootaxa 4012 (1), pp. 97-119 : 107-114

Chironius brazili , sp. nov.

Chironius flavolineatus — Bailey 1955:13 [partim]; Peters & Orejas-Miranda 1970:60 [partim]; Dixon et al. 1993:112 [partim].

Holotype. Adult male, MNRJ 17480, collected by A.C.A. Lopes in October 2008 at RPPN Santuário do Caraça (20º05’, 43º29’W, 1262m asl), municipality of Catas Altas, state of Minas Gerais, Brazil.

Paratypes. Eight specimens all from Brazil: adult female, IVB 3290, collected by T. Filadelfo in February 2013 at Poço Azul waterfall (15º36’03’’S, 48º03’16’’W, 1220m asl), Parque Nacional de Brasília, municipality of Brasília D.C.; adult female, CHUNB 19699, collected at municipality of Alto Paraíso de Goiás (14º12’S, 47º41’W, 1250m asl), state of Goiás; juvenile male, MNRJ 18936, collected by A.C.A. Lopes in April 21 2009 same data as the holotype; adult female, IVB 3342, collected by G.A. Cotta on January 1997 at district of Vila Del Rey (20º00’S, 43º56’W, 1050m asl), municipality of Nova Lima, state of Minas Gerais; adult female, MZUFBA 2448, collected by O.M. Sampaio in November 1986, municipality of Rio Acima (20º05’S, 43º47’W, 740m asl), state of Minas Gerais; adult female, MCNR 2790, collected at municipality of Conceição do Mato Dentro (19º02’S, 43º25’W, 685m asl), state of Minas Gerais; adult male, MCNR 3384, collected at municipality of Igarapé (20º04’S, 44º17’W, 810m asl), state of Minas Gerais; adult male, MCNR 4386, collected at municipality of Ouro Preto (20º19’S, 43º33’W, 1050m asl), state of Minas Gerais.

Diagnosis. Chironius brazili can be distinguished from all congeners by the following unique combination of states of characters: first third of body black or dark gray; vertebral stripe yellowish or creamish white, distinct from dorsals of nape and extending throughout almost whole body length; head dorsum tan to brown, distinct from background color of first third of body; cloacal shield frequently divided (96%); two to four rows of keeled dorsal scales at midbody; ventral ground color gradually darkening towards cloaca; region of medial constriction of hemipenis slightly covered with spinules separating calyces of apex from spines below region of constriction; in lateral view, sulcus spermaticus positioned on convex face of hemipenis; ascending process of premaxilla oblique anteroposteriorly to longitudinal axis of skull; optic fenestra not exceeding frontoparietal suture; posterior border of supratemporal exceeding braincase; dorsoventral axis of quadrate oblique mesolaterally, moving away from longitudinal axis of skull.

Comparisons. Chironius brazili is distinguished from all currently recognized congeners, except C. flavolineatus and C. diamantina , by having first third of body black or dark gray, vertebral stripe yellowish or creamish white, distinct from dorsals of nape and extending throughout almost whole body length, and head dorsum tan to brown distinct from background color of first third of body. Chironius brazili differs from C. flavolineatus (character states in parentheses) by having ventral ground color gradually darkening towards cloaca (vs. venter uniformly creamish white); region of medial constriction of hemipenis slightly covered with spinules separating calyces of apex from spines below region of constriction on asulcate side (vs. region of medial constriction with no spinules separating calyces of apex from spines below region of constriction on the asulcate side); in lateral view, sulcus spermaticus positioned on the convex face of hemipenis (vs. sulcus spermaticus positioned on the concave face of hemipenis in lateral view); ascending process of premaxilla oblique anteroposteriorly to longitudinal axis of skull (vs. perpendicular to longitudinal axis of skull); optic fenestra not exceeding frontoparietal suture (vs. exceeding frontoparietal suture); posterior border of supratemporal exceeding braincase (vs. not exceeding braincase); and dorsoventral axis of quadrate oblique mesolaterally, moving away from longitudinal axis of skull (vs. straight, not moving away from longitudinal axis of skull). Chironius brazili differs from C. diamantina (character states in parentheses) by having two to four rows of keeled dorsal scales at midbody (vs. six to ten); cloacal shield frequently divided (vs. entire).

Description of the holotype ( Fig. 7 ). Adult male; left and right hemipenes everted; head distinct from body; total length 1381 mm; SVL 845 mm; CL 536 mm; head length 287 mm; head width at broadest point 126 mm; snout length 86 mm; snout width 78 mm; body width at midbody 89 mm; body height at midbody 169 mm. Length/ width of rostral (4.4/ 2.6 mm); prenasal (2.4/ 2.5 mm); postnasal (1.6/ 1.8 mm); internasal (3.5/ 2.9 mm); loreal (2.8/ 1.3 mm); prefrontal (3.8/ 3.9 mm); prefrontal suture 2.7 mm; preocular (2.5/ 3.4 mm); supraocular (7.2/ 3.8 mm); frontal (7.3/6.0 mm); frontal-supraocular suture 5.9 mm; parietal (9.6/ 5.9 mm); parietal suture 6.2 mm; anterior temporal (5.9/ 2.6 mm); posterior upper temporal (5.7/ 4.2 mm); posterior temporals fused; first pair of chin shields (7.4/ 2.9 mm); second pair of chin shields (9.7/ 3.3 mm); horizontal eyes diameter 5.3 mm; vertical eyes diameter 4.0 mm. Loreal longer than high, separated from orbit by preocular; loreal contacting postnasal anteriorly, preocular posteriorly, prefrontal dorsally, and second and third supralabials ventrally; preocular single, separated from frontal by suture between supraocular and prefrontal; pupil rounded; postoculars two; anterior temporal 1/1; posterior temporals 2/1; five occipital scales contacting parietals; supralabials 9/9, fourth, fifth, and sixth contacting eye; infralabials 10/10, first to fifth contacting first pair of chin shields; fifth and sixth contacting second pair of chin shields; gulars three. Maxillary teeth 34. Dorsal scales rows 12/12/10; low density of apical pits on the scales of neck; no rows of keeled dorsal scales on the anterior portion of body; two rows of keeled dorsal scales at midbody; two rows of keeled dorsal scales at posterior portion of body; keels very strong, mostly at midbody. Ventrals 156; subcaudals 141; cloacal shield (10.6/ 3.9 mm) divided.

Color of the holotype in preservative (alcohol 70%) ( Fig. 7 ). Dorsal surface of head brown with darker frontal and parietal scales; snout region, postoculars, and temporal region brown; orbit encircled by black; supralabials creamish white with brown spots; infralabials, and ventral surface of head creamish white; indistinct postocular blotch. First third of body blackish gradually fading to brown anteroposteriorly; anterior portion of vertebral stripe yellowish, gradually darkening anteroposteriorly, well distinct until posterior third of body where it gradually merges into body coloration; anterior portion of vertebral stripe two scales wide. First third of ventral ground color creamish white gradually darkening towards cloaca, where venter is dark gray; incomplete slight transversal dark bars corresponding to posterior margins of ventrals visible mostly in first third of venter. Cloacal shield and anterior portion of the ventral surface of tail dark gray gradually lightening towards terminal caudal spine; subcaudal scales occasionally with black or dark gray edges.

Color pattern variation in preservative (alcohol 70%) ( Fig. 8 ). Postocular region without blotches or stripes (80%), with a dark blotch (17%), or with dark postocular stripe reaching postoculars, temporals, and last supralabials (3%). Dorsal ground color of body brown; dorsal scales may show white edges. Vertebral stripe with two (90%), one and a half (5%), or one (5%) scale wide. Venter with longitudinal lines (n = 71; 95%); ground color generally gray to brown ( Figs. 8 B–D), always lighter in first third of venter. Juveniles with dorsolateral ground color of body brown with lighter crossbands (n = 5) ( Fig. 8 C), indicating possible existence of ontogenetic variation.

Color in life ( Fig. 9 ). General color of head, venter and body similar to the color of the preserved specimens. Dorsal color pattern occasionally reaches ventral region, more evident in tail region; dorsal scales occasionally encircled by black or white ( Figs. 9 A, E–F); paraventral scales in first third of body with orange or light brown spots ( Figs. 9 A–D). Ventral scales gradually covered with orange or grayish coloration anteroposteriorly. Some hatchlings and adults may show dark or gray variegated dorsal color pattern.

Morphometric and meristic variation. Largest male (MZUSP 7566) 895 mm SVL, 560 mm CL, largest female (FUNED 1696) 862 mm SVL, 572 mm CL. Total length in males 410–1455 mm (n = 30), females 408– 1434 mm (n = 30); snout length in males 4.0– 9.3 mm (n = 35), females 3.5–10 mm (n = 33); snout width in males 3.3–8.4 mm (n = 35), 3.3–9.6 mm (n = 33) in females; head length in males 14.5–28.8 mm (n = 36), 13.5–31.9 mm (n = 34) in females; head width in males 6.3–13 mm (n = 35), 5.0– 19.3 mm (n = 34) in females; midbody width in males 3.8–15 mm (n = 34), 4.6–15.5 mm (n = 34) in females; midboby height in males 3–17.1 mm (n = 34), 5.1– 19.6 mm (n = 34) in females. Number of occipitals touching parietals 3–7 (x¯ = 4.52; s = 0.82; n = 40); gulars 3–7. Dorsal scales rows 12/12/10 (n = 75; 97.5%) or 12/12/8 (n = 2; 2.5%). Variation of other meristic and morphometric data for C. brazili is summarized in Table 2.

Ornamentation of dorsal scales. Apical pits in adults generally restricted to neck (n = 55; 92%), occasionally also being found at midbody and/or near cloacal region (n = 2; 3%), or apical pits rarely absent (n = 3; 5%). Generally, C. brazili shows conspicuous depressions similar to apical pits, in preocular, postoculars, loreal, temporals, and occasionally in supralabial scales. Rows of keeled dorsal scales along body show variation (see Table 2) but keels are generally more conspicuous in males than in females.

Hemipenis (n = 7, Fig. 3 ). Organ unilobed, cylindrical, and unicalyculate. Hemipenis with large spinulate and well developed calyces on most of the apical portion. Medial portion of hemipenis with pronounced constriction region slightly covered with spinules ( Fig. 3 D), separating calyces of apex from spines below region of constriction on the asulcate side. Medium to large curved spines covering lateral and asulcate sides and spinules covering sulcate side of hemipenis. Sulcus spermaticus simple and centrolineal, bordered by spinules along its extension, and positioned more laterally at basal portion of hemipenis. In lateral view, sulcus spermaticus positioned on the convex face of the organ. Basal portion of hemipenis with few spinules irregularly distributed.

TABLE 2. Summary of meristic characters for Chironius brazili , C. flavolineatus , and C. diamantina . The abbreviation are as follow: SL= supralabials; SO=supralabials contacting orbit; =infralabials; IL /CS=infralabials in contact with chin shields; PO=postocular; TEa= anterior temporals; TEp=posterior temporals; MT=maxillary teeth; KDA, KDM, and KDP=rows of keeled dorsal scales at anterior, midbody, and posterior portion of body, respectively; mean ± standard deviation; r=range; n=sample size. *Data from Fernandes & Hamdan (2014).

Cephalic glands and skulls. The cephalic glands of C. flavolineatus and C. brazili showed similar patterns ( Fig. 4 ), while the main osteological differences in the skull of these taxa ( Fig. 10 ) were those comparatively refereed in the sections “Diagnosis” and “Comparisons”.

Etymology. The epithet " brazili " is a patronymic honoring Vital Brazil Mineiro da Campanha (1865–1950), Brazilian scientist who discovered the specificity of snakebite serum and founded two centers of excellence in research and production of strategic biological products for public health: Instituto Butantan in 1899 and Instituto Vital Brazil in 1919. Despite being a doctor by training, Vital Brazil was among the first Brazilian researchers to be concerned with the correct identification of the snakes received at that time at Instituto Butantan. Vital Brazil was honored with some species of snakes, such as Rachidelus brazili Boulenger, 1908 , Drymoluber brazili ( Gomes, 1918) , and Bothrops brazili Hoge, 1954 , which we can say that is still a modest honor given his great contribution to the science.

Geographic distribution and natural history ( Figs. 6 , 11 ). Chironius brazili is distributed in Cerrado biome of Brazil throughout the states of Goiás, Federal District, Minas Gerais, and São Paulo, from 70 up to 1360m asl (generally 700–900m asl). An apparently disjunct population of C. brazili occurs in the state of Rio Grande do Sul, Brazil.

A female (IVB 3290; total length 995 mm) was observed in a gallery Forest of Parque Nacional de Brasília (1022m asl), foraging around 3:00 PM over rocks on the banks of a river (T. Filadelfo, pers. comm., Fig. 11 ). After approximation, the specimen adopted similar behaviors mentioned by Fernandes & Hamdan (2014) for C. diamantina . Regarding reproductive data, a single preserved female (CHUNB 3632) had five eggs in the oviduct.

Figures

FIGURE 3. Asulcate (A, D), sulcate (B, E), and lateral (C, F) views of the hemipenis of C. flavolineatus (upper, UFS 419) and C. brazili (lower, MZUFV 1746). Arrow indicates region of medial constriction of hemipenis slightly covered with spinules.

FIGURE 4. Lateral (A – C) and ventral (D) views of cephalic glands of C. flavolineatus (B, UFS 1329) and C. brazili (A, C, D, MCNR 2077). D. g. = Duvernoy gland; H. g. = Harder gland; i. g. = Infralabial glands; ls. g. = Lateral sublingual glands; ms. g. = Medial sublingual gland; n. g. = Nasal gland; p. g. = Premaxilar gland; and s. g. = Supralabial glands.

FIGURE 6. Geographic distribution of Chironius flavolineatus, C. brazili, and C. diamantina.

FIGURE 7. Dorsal (A, C) and ventral (B, D) views of the body and right (E) and left (F) lateral views of the head of the holotype of Chironius brazili (MNRJ 17480, SVL 845 mm, CL 536 mm) from Catas Altas, state of Minas Gerais, Brazil.

FIGURE 8. Color pattern variation in preservative of adult (A – B, MCNR 2790, SVL 840 mm, CL 537 mm) and juvenile (C – D, MNRJ 18936, SVL 256 mm, CL 154 mm) of Chironius brazili.

FIGURE 9. General view of adult of Chironius brazili in life (A – F). Photos by C. Cintra (A – B), I. Sazima (C), T. Filadelfo (D – E), and P. Machado (F).

FIGURE 10. Details of the osteological informative characters of C. flavolineatus (left column, UFS 1329) and Chironius brazili (right column, F, FUNED 41 and B, D, H, FUNED 1466). Position of the ascending process of premaxilla (A, B); Optic fenestra (C, D); posterior border of supratemporal (E, F); dorsoventral axis of quadrate (G, H).

FIGURE 11. Landscape of the Cerrado (A) and riparian forests (B) vegetal formations in the Parque Nacional de Brasília, where paratype of C. brazili (IVB 3290) was collected, municipality of Brasília, Federal District, Brazil. Photos by T. Filadelfo.