Chlorosoma Wagler, 1830

Arredondo, Juan Camilo, Grazziotin, Felipe G., Scrocchi, Gustavo J., Rodrigues, Miguel Trefaut, Bonatto, Sandro Luís & Zaher, Hussam, 2020, Molecular phylogeny of the tribe Philodryadini Cope, 1886 (Dipsadidae: Xenodontinae): Rediscovering the diversity of the South American Racers, Papéis Avulsos de Zoologia (Pap. Avulsos Zool., S. Paulo) 60, pp. 1-14 : 6-8

Genus Chlorosoma Wagler, 1830 resurrected

Type species: Coluber viridissimus Linneaus, 1758 , by original designation and monotypy.

Content: (two species) Chlorosoma laticeps (Werner, 1900) new combination; Chlorosoma viridissimum (Linneaus, 1758) .

Diagnosis: Chlorosoma can be distinguished from the other genera of Philodryadini by the following combination of characters: ventral and subcaudal scales strong- ly angulated laterally (keeled); ontogenetic change in color pattern, with juveniles exhibiting dark chevrons throughout the body dorsum and adults changing to a homogeneously green dorsum; ventral surface with a yellow, white or cream gular region (excluding infralabial scales) and green venter and tail; short hemipenes with reduced lateral enlarged spines.

Geographical distribution: Chlorosoma viridissimum occurs in the eastern lowlands of northern and central South America, including Amazonian forests of Colombia, Venezuela, Suriname, Guyanas, Ecuador, Peru, Brazil, and Bolivia. In Brazil this species also inhabits the ecotone between Amazonian and Cerrado biomes, and a single population is present in the lowland forest of the Atlantic coast of the Bahia state. Chlorosoma laticeps shows a disjunct distribution pattern, with records from central Bolivia in Santa Cruz and Cochabamba departments, and Southeastern Brazil in Espírito Santo, Minas Gerais and Santa Catarina states ( Zaher et al., 2008).

Etymology: The generic name is neuter, being a combination of the Greek words Chloros- (adjective, ΧΛωρός, meaning “bright green”) and -soma (noun, σῶμα, meaning“body”), in reference to the overall bright green coloration of the body in these species.The gender of the name Chlorosoma is grammatically neuter ( Amaral 1929a, b, c, 1932) since the meaning given by Wagler (1830) was of a “green snake.” Therefore, the correct spelling for the type species of the genus is Chlorosoma viridissimum .

Comment: Wagler (1830) used the same contribution to erect the genera Chlorosoma and Philodryas for the species Coluber viridissimus Linneaus 1758 and Coluber olfersii Liechtenstein 1823 , respectively.Shortly after, Günther (1858), redefined the genus Philodryas to allocate P. aestivus , P. dorsalis (= Ialtris ), P. goudotii (= Ithycyphus ), P. olfersii , P. serra (= Tropidodryas ), Philodryas schottii (= patagoniensis ), and Philodryas viridissimus . Considering that Wagler (1830) described Chlorosoma before Philodryas on page 185, Amaral (1929a, b, 1932) decided to apply the Principle of Priority and assigned all species of Philodryas known at the time to the genus Chlorosoma (i.e., C. aestivum , C. arnaldoi , C. burmeisteri (= trilineata ), C. mattogrossense , C. olfersii , C. schottii (= patagoniensis ), C. psammophideum , and C. viridissimum ). However, Parker (1932) pointed out that Günther’s (1858) generic classification using the name Philodryas for these species had priority under the Principle of the First Reviser (Art. 24.2.2, ICZN 1999). Thus, the genus Chlorosoma is available for the recovered evolutionary lineage including Philodryas viridissima and Philodryas laticeps .