Tuesday, January 8, 2019

[Herpetology • 2019] Rhadinaea eduardoi • A New Species of Forest Snake of the Genus Rhadinaea (Squamata, Dipsadidae) from Tropical Montane Rainforest in the Sierra Madre del Sur of Oaxaca, Mexico

Rhadinaea eduardoi 
Mata-Silva, Rocha, Ramírez-Bautista, Berriozabal-Islas & Wilson, 2019

Content of the dipsadid genus Rhadinaea has changed considerably since Myers’ 1974 revision. Three species groups are recognized currently in the genus. Our fieldwork in Oaxaca in June 2018 produced a single specimen of Rhadinaea considered to represent a new taxon. This new species is described from converted Premontane Wet Forest in the municipality of Santa Catarina Juquila in the Sierra Madre del Sur of southern Oaxaca, Mexico. It is most closely related to Rhadinaea laureata, from which it can be distinguished easily by color pattern and scutellation, and represents a species group distinct from the other three occupying the genus.

Keywords: Morphology, new serpent species, Santa Catarina Juquila municipality, Southern Mexico, taxonomy

Figure 2. Head and anterior portion of body of holotype of Rhadinaea eduardoi.

Figure 3. Holotype of Rhadinaea eduardoi in life. 

Rhadinaea eduardoi sp. n. 

Common name: English: Eduardo’s forest snake. 
Spanish: Hojarasquera de Eduardo

Diagnosis: A snake of the genus Rhadinaea that can be distinguished from all congeners by the following combination of morphological features: supralabials 7, with 3rd and 4th entering orbit; 120 ventrals; 71 subcaudals; one subpreocular (lower preocular); 17 dorsal scales throughout body; a head pattern lacking postorbital pale markings but having a pale line extending from the lower rear quadrant of the eye to the ultimate supralabial and slightly beyond, and a midbody dorsal color pattern of a lateral series of black dots in the lower apex of the scales of row V and a middorsal line confined to the middorsal scale row consisting of a series of disjunct spots on the posterior apex of otherwise dark brown scales.

Etymology: This species is named in honor of Eduardo Mata-Silva, collector of the holotype. Eduardo is the younger brother of the senior author of this paper, is a resident of Río Grande, Oaxaca, and is a highly valued member of our field crew working in Oaxaca. He also outshines the rest of the crew when it comes to finding snakes, as evidenced by his discovery of the holotype of the snake described herein.

Habitat and natural history observations: Rhadinaea eduardoi is resident in an area of converted Premontane Wet Forest, which presently supports a plantation of shade-grown coffee (Fig. 5). The holotype was found active at 1800 hrs on leaf litter approximately 10 m from a stream after a very light rain. Other herpetofaunal species encountered at this site were the anurans Craugastor pygmaeus, Ptychohyla leonhardschultzei, and Exerodonta sumichrasti, and the lizards Norops sp. and Holcosus undulatus.

Figure 5. Habitat where holotype of Rhadinaea eduardoi was found.

 Vicente Mata-Silva, Arturo Rocha, Aurelio Ramírez-Bautista, Christian Berriozabal-Islas and Larry David Wilson. 2019. A New Species of Forest Snake of the Genus Rhadinaea from Tropical Montane Rainforest in the Sierra Madre del Sur of Oaxaca, Mexico (Squamata, Dipsadidae).  ZooKeys. 813: 55-65. DOI: 10.3897/zookeys.813.29617

Resúmen: La conformación del género Rhadinaea ha cambiado considerablemente desde la revisión de Myers en 1974. Tres grupos de especies son reconocidos actualmente en el género. Nuestro trabajo de campo en Oaxaca en junio de 2018 produjo un espécimen de Rhadinaea que consideramos que representa un nuevo taxón. Describimos esta nueva especie de bosque húmedo premontano en el Municipio de Santa Catarina Juquila en la Sierra Madre del Sur en el sur de Oaxaca, México. Esta especie está más estrechamente relacionada con Rhadinaea laureata, de la cual se puede distinguir fácilmente por medio del patrón de color y escutelación, y representa un grupo distinto a los tres que forman parte del género.
Palabras claves: Morfología, nueva especie de serpiente, municipalidad de Santa Catarina Juquila, el sur de México, taxonomía