Chironius gouveai ENTIAUSPE-NETO, LÚCIO-LYRA, KOCH, MARQUES-QUINTELA, DIESEL-ABEGG & LOEBMANN, 2020
Can you confirm these amateur observations of Chironius gouveai?
|Higher Taxa||Colubridae, Colubrinae, Colubroidea, Caenophidia, Alethinophidia, Serpentes, Squamata (snakes)|
|Common Names||E: Gouvea’s Sipo|
Portuguese: Cobra-cipó de Gouvêa
|Synonym||Chironius gouveai ENTIAUSPE-NETO, LÚCIO-LYRA, KOCH, MARQUES-QUINTELA, DIESEL-ABEGG & LOEBMANN 2020|
Chironius bicarinatus — Dixon et al. 1993: 59
Chironius bicarinatus — Achaval and Olmos 1997: 68
Chironius bicarinatus — Lema 2002: 55
Chironius bicarinatus — Carreira et al. 2005: 99 (in part, misidentification).
|Distribution||Brazil (Rio Grande)|
Type locality: Tapes (30°28’46.7’’S; 51°23’46.1’’W), Rio Grande do Sul, Brazil
|Types||Holotype: CHFURG 4394 (tissue sample CT2635), collected by Fernando Marques Quintela, an adult male.|
Paratypes: ZUFSM 2908, roadkill adult male, collected by Vin ́ıcius Caldart and Samanta Iop on 25 April 2011 on Bage ́ municipality, Rio Grande do Sul, Brazil; ZFMK 103132 (Ex-CHFURG 1504; Fig. 6C,D; tissue sample CT453), adult male collected by Daniel Loebmann on 3 February 2012, Rio Grande municipality, Rio Grande do Sul, Brazil; MCP 2631, an adult female collected by Marcos Di-Bernardo on 17 October 1987 at Rodeio Bonito, Sa ̃o Francisco de Paula municipality, Rio Grande do Sul, Brazil; CHFURG 4823, 4824, adult male and female collected by Marcelo Burns on an unknown date of 2016 at Ilha da Torotama, Rio Grande municipality, Rio Grande do Sul, Brazil; MCP 8968 an adult male collected by students of the Gomercinda Dornelles Fountoura school on an unknown date, Encruzilhada do Sul municipality, Rio Grande do Sul, Brazil; MCP 12762, an adult male collected by Felipe Quadros on 24 January 2002 at Corsan-Sitel, Triunfo municipality, Rio Grande do Sul, Brazil.
|Diagnosis||Diagnosis: Chironius gouveai is distinguished from all its congeners by the following combination of characters: (1) 12/12/10 dorsal scales; (2) preocular single; (3) two postoculars; (4) loreal present, single, rectangular; (5) temporals 1+1 (rarely 1+2); (6) supralabials 8–10, with fourth to sixth in contact with orbit; (7) 8–10 infralabials, with first to sixth in contact with chin shields; (8) ventrals 153–165 (153–165 in males, 155–164 in females); (9) subcaudals 103–146, paired (129–142 in males, 103–146 in females); (10) dorsal coloration background olive green, with black margins and diffuse blue pigmentation, with two longitudinal black stripes and light yellow vertebral stripe, which gradually dissipates to the tail (in preservative, olive green surfaces turn metallic gray and yellow surfaces turn white); (11) ventral surface immaculate white, with discrete black margins on the ventral scales, second third with olive green background, gradually becoming yellow, and black margins on ventral scales, last third with yellow background coloration and strong black margins, on ventral and subcaudal scales; (12) body length moderate, SVL 170–860 mm; (13) head length moderate, 2.44–5.45% of SVL; (14) tail length large, 47–63% of SVL; (15) hemipenis unilobed, unicalyculate, cylindrical, apex with smooth calyces, with spinules restricted to proximal portion, near the medial area; (16) lacrimal foramen with small projection on the anteroventral margin.|
Comparisons: The new species is distinguished from C. bicarinatus (characters in parentheses) on the basis of the presence of strong black margins on the ventral scales, usually more visible near the tail (absent), white gular coloration in life (yellow), reticulated dorsal pattern in adults (uniform green), dorsal pattern with scattered black blotches in juveniles (black transversal bars), absent or vestigial postocular stripe (present on adults and juveniles, rarely vestigial on juveniles), hemipenis smooth calyculate apex (spinulate calyces), presence of lacrimal foramen with a small projection on the anteroventral margin (absent), presence of ventral expansion of the septomaxillar wall (absent), anterior portion of the supratemporal bone surpassing the parietal–pro-otic suture (posterior or above suture), posterior portion of supratemporal slightly curved (straight). Further comparisons are made in Table 1. It is also noteworthy that the new species is, to our current knowledge, not sympatric with C. bicarinatus in most of its range, having a small contact zone in the Araucaria moist forests of Parana ́ , southern Brazil.
The new species differs from C. fuscus, C. leucometapus, C. grandisquamis, and C. scurrulus in having 12/12/12 or 12/ 12/10 dorsal scale rows ([16–13]/12/[10–8]; 10/12/10; 10/10/ 10; 10/10/8); from C. brazili, C. carinatus, C. diamantina, C. dixoni, C. flavolineatus, C. flavopictus, C. foveatus, C. maculoventris, C. laevicollis, C. monticola, C. multiventris, C. quadricarinatus, C. spixii, and C. vincenti in having a unique dorsal coloration composed of olive green background, with black margins and diffuse blue pigmentation, with two black stripes with a clear vertebral stripe, which gradually dissipates to the tail (distinct combinations of uniform green, black, red, olive or brown, with vertical bands, horizontal stripes, light markings or fleckings).
The distinction between the new species and C. exoletus has been proven as challenging in preserved specimens, considering the convoluted taxonomic status of the latter species; as pointed out by Giraudo (2001), the diagnostic dorsal scale row formulae provided by Dixon et al. (1993) encompasses the intraspecific variation of C. bicarinatus. Considering that C. exoletus has an immense geographic distribution range, from Costa Rica and Panama to most of the South America east and west of the Andes, with its southernmost records at Argentina and southern Brazil, added to its extensive intraspecific variation, we herein refer to C. exoletus as strictly the type series of Linnaeus (1758), the specimen ZMUU 135, redescribed by Hoge et al. (1978), tentatively assigning the sympatric populations somewhat congruent with the former description as C. cf. exoletus, to avoid creating taxonomic instability within the group. A taxonomic revision of this species is currently underway, and this group likely constitutes a species complex (V. Sudre, personal communication).
The new species is distinguished from C. exoletus on the basis of its coloration pattern (uniform clear brown with bluish gray on the nuchal region), infralabial scale counts (11 infralabials with first five in contact with anterior mentonian scale), and dorsal scale counts (14/12/8 smooth dorsals).
Chironius gouveai can also be distinguished from the sympatric C. cf. exoletus populations on the basis of its dorsal scale rows (12/12/8 or 12/10/10), distinct dorsal coloration and pattern (uniform bluish gray top of head in preservative, dark olive green in life, with irregular black and white blotches over a brown and olive background on the dorsum), and hemipenis morphology (spinulate calyces on its distal portion).
|Etymology||The species etymology gouveai honors Paulo Roberto Cardoso Gouvêa, first author’s grandfather, who is largely responsible for his scientific career, and has been the most significant source of inspiration, ethics, and funding for the author’s research since then. The name is treated as a noun in apposition.|