Taxonomic revision of Chironius flavolineatus (Jan, 1863) with description of a new species (Serpentes: Colubridae)

Abstract

We conducted a taxonomic review of Chironius flavolineatus on the basis of continuous and discrete morphological characters. We recognize a new species which is distinguished from all currently recognized congeners by the following unique combination 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; posterior temporal scales ranging one to four; cloacal shield frequently divided; two to four rows of keeled dorsal scales at midbody; venter 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 fenestrae not exceeding frontoparietal suture; posterior border of supratemporal exceeding braincase; dorsoventral axis of quadrate oblique mesolaterally, moving away from longitudinal axis of skull. Furthermore, we provide data on morphological variation, distribution, and an emended diagnosis for C. flavolineatus.

Inclusão, exclusão e reinclusão: Chironius brazili (Serpentes, Colubridae) no Rio Grande do Sul, sul do Brasil

“…The meristic and morphometric variables found in specimens of Rio Grande do Sul (Table 1), as well as their respective dorsal and ventral coloration, are in accordance with the described for the species (Hamdan and Fernandes, 2015).…”

“…9/9 9/9 9/9 9/9 SO 5-6 5-6 5-6 5-6 IL (CS) 10/10 (1-5) 11/10 (1-6/1-5) 9/9 (1-5) 10/10 ( Bérnils (2009) commented the occurrence of C. flavolineatus in the southern portion of Paraná, in areas above 800m asl. This data was apparently not analyzed by Hamdan and Fernandes (2015), considering their lack of specimens for this state. However, considering that C. flavolineatus occurs mainly in lowlands and has a centro-setentrional distribution in Brazil, we speculate that the records in Paraná actually consist with C. brazili, being the higher altitudes and the Central Southern distribution consistent with records of the species.…”

“…Accordingly to Hamdan and Fernandes (2015), C. brazili is distributed in Brazilian Cerrado throughout the states of Goiás, Federal District, Minas Gerais, and São Paulo, from 70 up to 1360m asl (generally 700-900m asl), occurring in sympatry with C. flavolineatus in its northern distribution portion, the latter being usually found between 100-400m asl. 9/9 9/9 9/9 9/9 SO 5-6 5-6 5-6 5-6 IL (CS) 10/10 (1-5) 11/10 (1-6/1-5) 9/9 (1-5) 10/10 ( Bérnils (2009) commented the occurrence of C. flavolineatus in the southern portion of Paraná, in areas above 800m asl.…”

“…In the state of Rio Grande do Sul, there are literature records for Chironius bicarinatus (Wied, 1820), Chironius brazili Fernandes, 2015, Chironius exoletus (Linnaeus, 1758) and Chironius maculoventris Dixon, Wiest andCei, 1993 (Lema 1994;Abegg and Entiauspe, 2012;Hamdan and Fernandes, 2015;Santos et al, 2015).…”

“…2016). Hamdan and Fernandes (2015), in the revision of C. flavolineatus, provide a geographical distribution for C. brazili in the Central and Southeastern Cerrado of Brazil, and comment that "an apparently disjunct population of C. brazili occurs in the state of Rio Grande do Sul" with two isolated records in this state, providing no further comments on its biogeographical implications. Di-Bernardo et al (2004), in its exclusion proposal, argued that C. flavolineatus lacked voucher specimens and had not been recorded in the other Southern Brazilian states or neighboring countries.…”