Chironius diamantina Fernandes & Hamdan, 2014, sp. nov.
Creators: name: Fernandes, Daniel Silva
name: Hamdan, Breno
Publisher: name: Zenodo
Year: 2014
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Reptilia
Squamata
Colubridae
Chironius
Chironius diamantina

description: Chironius diamantina, sp. nov.
Figs. 1–6
Chironius flavolineatus (Jan, 1863) — Freitas & Silva (2007: 182, fig. MAF, Lençóis, BA) Chironius flavolineatus (Jan, 1863) — Hamdan & Lira-da-Silva (2012: 43, fig. 2k) Holotype. Adult female, MZUFBA 1657, collected in November 2005, no collector data, from the municipality of Morro do Chapéu (11o 33’ 9’’S, 41o 9’ 27’’W, about 1000 m above sea level; asl hereafter), oriental zone of Chapada Diamantina, state of Bahia, Brazil.
Paratypes. All specimens from the state of Bahia, Brazil. Adult female, MZUFBA 2394, tail damaged, collected on March 13, 2013 by B. Hamdan, in the municipality of Palmeiras, village of Vale do Capão (12º 30’ 50’’S, 41º 34’ 39’’W, 1310 m asl), in an area of Campos Rupestres along the bank of the river of Cachoeira da Fumaça waterfall; adult male, AAGARDA 7191, collected on January 2013 by W. Pessoa, in the municipality of Palmeiras, village of Vale do Capão, in a tropical grassland environment near Cachoeira Águas Claras waterfall; adult male, UEFS 1519, no collector data, from the municipality of Palmeiras (12º 36’ 34’’S, 41º 30’ 24’’W, 1000 m asl); adult male, MZUSP 7804, tail damaged, and adult female, MZUSP 7805, both collected in 1980 by M. T. Rodrigues, in the municipality of Morro do Chapéu. All other specimens collected in the municipality of Rio de Contas (13o 26’ 30’’S, 41o 50’ 28’’W, about 1000 m asl), collection data from A.J.S. Argôlo. Adult male, MZUESC 2633, collected between 22 November 2001 and 26 June 2002, at Bittencourt farm; adult female, MZUESC 2102, tail damaged, collected between 26 May 2001 and 21 November 2001, at Brejo farm; adult male MZUESC 2642, tail damaged, adult female MZUESC 2643, adult female MZUESC 2644, tail damaged, and adult female MZUESC 2645, all four specimens collected between 22 November 2001 and 26 June 2002 at Brejo farm.
Diagnosis. Chironius diamantina can be distinguished from all congeners by the following combination of states of characters in preserved specimens: first third of body black or dark gray; vertebral stripe yellowish or creamish white, distinct from dorsals of nape and extending throughout almost the whole body length; head dorsum tan to brown, distinct from background color of first third of body; posterior temporal scales two to four; cloacal shield entire; six to ten rows of keeled dorsal scales at midbody; ventral scales with dark edges forming conspicuous transverse bars virtually throughout whole belly length; ventral surface of tail with conspicuous longitudinal dark stripes (in “zigzag”) in midventral portion of subcaudals; 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.
Comparisons. Chironius diamantina is distinguished from all currently recognized congeners, except C. flavolineatus, by having the combination of first third of body black or dark gray, vertebral stripe yellowish or creamish white extending from nape throughout almost the whole body length, and head dorsum tan to brown distinct from background color of first third of body. Additionally, C. diamantina differs from C. flavolineatus (character states in parentheses) by having posterior temporals two to four (vs. single posterior temporal); cloacal shield entire (vs. divided); six to ten (vs. maximum of four rows of keeled dorsal scales at midbody); ventral scales with dark edges forming conspicuous transverse bars virtually throughout whole belly length; conspicuous dark longitudinal stripes (in “zigzag”) in the midventral portion of subcaudals (vs. ventrals and subcaudals uniformly creamish white); region of medial constriction of hemipenis slightly covered with spinules separating calyces of apex from spines below region of constriction (vs. region of medial constriction indistinct); in lateral view, sulcus spermaticus positioned on convex face of hemipenis (vs. sulcus spermaticus positioned on concave face of hemipenis in lateral view). Refers to Table 1 for additional qualitative characters to distinguish C. diamantina and C. flavolineatus.
Description of the holotype (Fig. 1). Adult female; head distinct from neck; body slightly thinner in anterior portion; total length 1018 mm; SVL 645 mm; TL 373 mm; head length 231 mm; head width 126 mm; snout length 86 mm; snout width 78 mm; body width at midbody 110 mm; body height at midbody 128 mm. Length/width of rostral (4.5/ 2.1 mm); prenasals (1.7/ 1.8 mm); postnasals (1.6/ 1.7 mm); internasals (2.7/ 2.4 mm); loreals (2.2/ 1.3 mm); prefrontals (3.0/3.0 mm); prefrontal suture 2.5 mm; preoculars (1.7/3.0 mm); supraoculars (5.5/ 2.8 mm); frontal (6.5/ 4.9 mm); frontal-supraocular suture 4.1 mm; parietals (8.3/ 4.2 mm); parietal suture 6 mm; anterior temporals (4.4/ 2.5 mm); posterior upper temporal (3.2/ 1.5 mm); posterior lower temporal (4.5/ 2.2 mm); first pair of chin shields (6/ 2.1 mm); second pair of chin shields (8.3/ 2.1 mm); horizontal eyes diameter (4.1/ 4.5 mm); vertical eyes diameter (3.5/ 3.4 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 2/2; five occipital scales contacting parietals; supralabials 9/9, fourth, fifth, and sixth contacting orbit; 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 33. Dorsal scales rows formula 12/12/10; low density of apical pits on scales of neck; two rows of keeled dorsal scales at anterior portion of body; ten rows of keeled dorsal scales at midbody; six rows of keeled dorsal scales at posterior portion of body; keels very strong, mostly at midbody. Ventrals 161; subcaudals 137; cloacal shield entire (4.1/ 8.4 mm).
Color of the holotype in preservative (alcohol 70%) (Fig. 1). Head dorsum uniformly brown; orbit slightly encircled by black; supralabials, infralabials, and ventral surface of head creamish white; dark postocular stripe reaching postoculars, temporals, and last supralabials (Fig. 1 E–F). First third of body dark gray gradually fading anteroposteriorly; first portion of vertebral stripe creamish white, gradually darkening anteroposteriorly, well distinct until posterior third of body; anterior portion of vertebral stripe 1.5 scale wide (Fig. 1 C). Row of paraventral scales in first third of body stained by black or dark brown (Fig. 1 E–F). Venter ground color creamish yellow to grayish, conspicuously marked by transversal dark bars corresponding to posterior margins of ventrals; transversal dark bars incomplete on anterior portion of belly (Fig. 1 D). Cloacal shield creamish white with gray spots; anterior portion of ventral surface of tail grayish, gradually getting lighter towards terminal caudal spine; conspicuous dark longitudinal stripes (in “zigzag”) along midventral portion of subcaudals (Fig. 1 B).
Color pattern variation (Figs. 1–2). In alcohol 70%, color pattern of head dorsum possibly reaching lateral regions of head. Dorsal ground color of body dark gray, usually homogeneous; dorsum color pattern may attain lateral edges of ventrals, more conspicuous on tail region. Vertebral stripe 1–2 dorsal scales wide. Row of paraventral scales in first third of body creamish white. Conspicuous lateral stripe on tail region (Fig. 2 F). Venter ground color generally gray, usually lighter on first third; ventral surface of tail creamish white (Fig. 2 B, H).
Color in life (Fig. 3). Head dorsum and snout brownish distinct from anterior portion of body; supralabials creamish white or yellowish; postocular stripe black or grayish; postocular stripe reaching postoculars, temporals, and occasionally last supralabials; infralabials and ventral surface of head creamish white. Dorsolateral ground color of body black, brown or grayish; first third of body darker than rest of dorsum; paraventral region brownish, lighter than rest of dorsum; dorsal scales generally black edged. Vertebral stripe golden extending from dorsal scales of nape to last third of dorsum of body where it gradually merges into body coloration. Venter ground color creamish white or light gray, conspicuously marked by transversal black or dark gray bars, especially after first third of belly; transversal bars correspond to posterior margins of ventrals (Fig. 3 F). Ventral surface of tail light gray with conspicuous black longitudinal stripes (in “zigzag”) along midventral portion of subcaudals. A single juvenile, not collected, showed dorsolateral ground color of body light brown with conspicuous light gray cross bands along the dorsum, which are not observed in adult specimens, and vertebral stripe extending from dorsal scales of nape to approximately midbody (Fig. 3 H).
Morphometric and meristic variation. Largest male (MZUESC 2633) 720 mm SVL, 391 mm TL, largest female (MZUFBA 2394) 895 mm SVL, tail damaged. Total length in males 885–1111 mm (n=3), females 701–1018 mm (n=4); snout length in males 6.4–8.7 mm (n=4), females 6.1–11.8 mm (n=6); snout width 6.3–7 mm in males (n=4), females 4.3–10 mm (n=6); head length in males 22.2–26.3 mm (n=4), females 19.3–33.2 mm (n=7); head width in males 9.3–11.2 mm (n=4), 7.6–13.6 mm (n=7) in females; body width in midbody in males 8.8–12.7 mm (n=4), females 6.4–13.8 mm (n=7); body height in midbody in males 7.2–12.2 mm (n=4), 6.1–12.8 mm (n=7) in females. Variation of meristic and other morphometric data for C. diamantina are summarized in Table 1. Rows of keeled dorsal scales along body show variation (see Table 1) but keels are generally more conspicuous in males than in females.
diagnostic characters (in bold) for both C. diamantina and C. flavolineatus. SO=supralabials contacting orbit; TEp=posterior
temporals; KDA, KDM, and KDP=rows of keeled dorsal scales at anterior, midbody, and posterior portion of body,
respectively; TB=ventrals with posterior dark edges forming transverse bars; LS=dark longitudinal stripes in midventral
portion of subcaudals; CH = region of medial constriction of hemipenis; SS=position of sulcus spermaticus in lateral view of
hemipenis; mean ± standard deviation; r=range; n=sample size.
Hemipenis (n=3, Fig. 4). Organ unilobed, cylindrical, and unicalyculate. Hemipenis with large spinulate and well developed calyces on most apical portion. Medial portion of hemipenis with pronounced constriction region scattered with spinules, separating apical calyces from spines on hemipenial body. Medium to large curved spines covering lateral and assulcate sides and spinules covering sulcate side of organ. Sulcus spermaticus simple, centrolineal, and bordered by spinules along its extension. Sulcus spermaticus positioned more laterally at basal portion of hemipenis, gathering more centralized position from the end of proximal third of hemipenis. In lateral view, sulcus spermaticus situated on convex face of the organ. Basal portion of hemipenis with few spinules irregularly distributed.
Etymology. The specific name, a noun in apposition, refers to the Chapada Diamantina, central region of the state of Bahia from where the new species was described.
Geographic distribution and natural history. The new species is known from municipalities of Morro do Chapéu, Rio de Contas, and Palmeiras in the Chapada Diamantina, state of Bahia, Brazil (Fig. 5). All available specimens were collected in areas up to 1000 m asl.
An individual was observed foraging around 3:00 PM on the banks of a rocky river in an area of Campos Rupestres near Cachoeira da Fumaça waterfall (1148 m asl), village of Vale do Capão, Municipality of Palmeiras, Bahia (Fig. 6). A few minutes later plunged into the river and remained there for about two minutes. When disturbed the specimen tried to escape, but when facing the observer opened its mouth, adopted the “S” posture, and attempted to bite. The specimen also showed the behavior of turning sideways along its axis when head was restrained.
description: Published as part of Fernandes, Daniel Silva & Hamdan, Breno, 2014, A new species of Chironius Fitzinger, 1826 from the state of Bahia, Northeastern Brazil (Serpentes: Colubridae), pp. 563-575 in Zootaxa 3881 (6) on pages 564-570, DOI: 10.11646/zootaxa.3881.6.5, http://zenodo.org/record/226528