Thursday, October 20, 2016

Persian Gulf Sea Snakes

Microcephalophis cantoris, a new record for the Persian Gulf
The Persian Gulf is a semi-enclosed shallow marine environment with a mean depth of about 35 meters lying in a subtropical and hyper-arid region in the northwestern Indian Ocean. It is considered a young sea (~15,000 years) with an impoverished biodiversity. Biota living in the Gulf must adapt to high temperatures and a hypersaline environment. Sea surface temperature in the Gulf varies from 18 to 34°C throughout the year and salinity is more than 39 ppt in most areas. Populations of sea snakes in the Persian Gulf are peculiar because the Gulf is the westernmost extent of sea snakes (with the exception of H. platurus, which is also found in the east coast of Africa) and because the Persian Gulf can be considered as an excellent natural laboratory to study the adaptive responses of the rapidly evolving sea snakes to high salinities and fluctuating temperatures. Extant knowledge of sea snake diversity in the Persian Gulf and its adjacent waters is based on  studies by Smith and Volsøe in the first half of the 20th century. They documented nine species of sea snakes in the area. Recently, taxonomy of the true sea snakes has been revised based on comprehensive molecular phylogenetic analyses allocated to the genera Enhydrina Gray, 1849, Lapemis Gray, 1835 and Pelamis Daudin, 1803 to the single genus Hydrophis and the Small-headed Sea Snake previously known as Hydrophis gracilis is now assigned to the genus Microcephalophis. A series of field surveys carried out in 2013 and 2014 throughout Iranian coastal waters of both gulfs did a comprehensive sampling of sea snakes in the area. In a new paper by Rezaie-Atagholipour and colleagues (2016) presents an illustrated and updated checklist and identification tool for sea snakes in the Persian Gulf and Gulf of Oman The list is based on new material and a review of the literature. This checklist includes ten species of marine hydrophiines, of which one, Microcephalophis cantoris (Günther, 1864), is a new record for the area.

Rezaie-Atagholipour M, Ghezellou P, Hesni MA, Dakhteh SMH, Ahmadian H, Vidal N (2016) Sea snakes (Elapidae, Hydrophiinae) in their westernmost extent: an updated and illustrated checklist and key to the species in the Persian Gulf and Gulf of Oman. ZooKeys 622: 129-164. doi: 10.3897/zookeys.622.9939

Friday, August 26, 2016

A New Species of Helicops from Minas Gerais, Brazil

Helicops nentur. 
Helicops is a genus of 16 species of Neotropical watersnakes. Using morphological and genetic data, Costa and colleagues (2016) identify a new species of this genus in the most recent issue of Herpeptologica. The new species occurs from southeastern to northern Minas Gerais, Brazil. The new species, Helicops nentur has  17-17-15 dorsal scale rows; 111–117 ventral plates; 41–56 subcaudals without keels; nasal entire; 18–21 + 2 maxillary teeth; and the hemipenis is bilobed. At present the new species is known only from five localities in Minas Gerais: The distribution of this species is in the Bahia Interior Forest ecoregion (Tropical and Subtropical Moist Broadleaf Forests biome), its border with the Cerrado ecoregion (Tropical and Subtropical Grasslands, Savannas, and Shrublands biome), and the ecotone between the Atlantic Dry Forest and the Caatinga ecoregions (Tropical and Subtropical Dry Broadleaf Forests biome and Deserts and Xeric Shrublands biome). This indicates that Helicops nentur might occupy different environments and climatic conditions. The distance between collection localities also suggests that there are many distribution gaps in the range of the species. The name nentur is formed by the words nen (water) and tur (ruler, master), meaning “master of waters,” a reference to the aquatic habits of Helicops.

Costa, H. C., D. J. Santana, F. Leal, R. Koroiva, and P. CA Garcia. 2016. A New Species of Helicops (Serpentes: Dipsadidae: Hydropsini) from Southeastern Brazil. Herpetologica 72 (2):157-166.

Sunday, July 10, 2016

Abstract: Diet, female reproduction and conservation of Jagor’s water snake, Enhydris jagorii in Bung Ka Loh wetland, Uttaradit province, Thailand

Diet, female reproduction and conservation of Jagor’s water snake, Enhydris jagorii in Bung Ka Loh wetland, Uttaradit province, Thailand

Jagor’s water snake (Enhydris jagorii) is a freshwater snake that is endemic to the Chao Phraya-Ta Chin basin, Thailand. However, habitat change and destruction are the main threats to this snake, where a large area of the wetland has been rapidly transformed into urban and agricultural areas. Moreover, uncontrolled fishing seriously threatens the remaining population of this snake. In order to protect this species, information on its natural history is required. This study was conducted in the Bung Ka Loh wetland during October, 2010 to August, 2014 when 108 specimens of this species were collected. Analysis of the stomach contents revealed that it is piscivorous, with cyprinids being the dominant prey. Prey items were usually less than 10% of the snake body mass and multiple prey items were occasionally found. No significant difference in diet was noted between the sexes. In addition, predation on this snake by Cylindrophis ruffus was first recorded in this study. The smallest gravid female collected had a snout-vent length of 34.0 cm. The clutch size and mass ranged from 1 to 28 embryos and 3.1 to 123.0 g, respectively, and both of these quantities increased significantly with increased female size. Reproduction was possibly seasonal and occurred in the rainy season. A preliminary study of other wetlands in the central plain of Thailand failed to detect the existence of this species. Accordingly, the conservation status of this species should be changed from Data Deficient to Critically Endangered.

Hydrops caesurus Scrocchi, Ferreira, Giraudo, Avila and Motte 2005

Hydrops caesurus Scrocchi, Ferreira, Giraudo, Avila and Motte 2005. Type locality: Departamento Itapúa, Isla Paloma, Canal de los Jesuitas, Paraguay.
Hydrops triangularis bolivianus — Williams and Couturier 1984
Hydrops triangularis — Álvarez and Aguirre 1995

Distribution. Northeast Argentina and Paraguay. The distribution is disjunct from other members of the genus. It inhabits temperate and subtropical latitudes. Type locality: Departamento Itapúa, Isla Paloma, Canal de los Jesuitas, Paraguay.

Helicops angulatus (Linnaeus, 1758)

Coluber angulatus Linnaeus 1758: 217. Type locality: “Asia” (in error).
Coluber alidras Linnaeus 1758:
Coluber Surinamensis Shaw 1802: 460
Natrix aspera Wagler 1824: 37
Helicops angulatus — Wagler 1830: 171
Helicops fumigatus Cope 1868: 308
Helicops cyclops Cope 1868: 309
Uranops angulatus — Sclater 1891: 45
Helicops angulata — Beebe 1946: 28

Distribution, Venezuela (Amazonas, Apure, Bolivar, Monagas, Delta Amacuro, Sucre, Portuguesa, Anzoátegui, Guárico, Cojedes), Colombia, Brazil (Pará, Rondonia, Goias, Mato Grosso, Sergipe, S Ceará, Acre etc.), Bolivia, Peru, Trinidad, Ecuador, French Guiana. 

Hydrops triangularis (Wagler, 1824)

Elaps triangularis Wagler 1824: 5. Type locality: Ega (= Tefé) Lago Tefé, at confluence with Rio Amazon, Brazil.

Hydrops triangularis - Wagler 1830: 170
Hydrops triangularis bassleri Roze 1957:83
Hydrops triangularis bolivianus Roze 1957:86
Hydrops triangularis fasciatus Roze 1957:76
Hydrops triangularis neglectus Roze 1957:81
Hydrops triangularis venezuelensis Roze 1957:78

Distribution. Amazonas, Orinoco and Guyana drainages includes Bolivia, Venezuela, Guyana, Surinam, French Guiana, Trinidad, E Peru, Ecuador, Brazil, Colombia, and Argentina. Type locality: Ega (= Tefé) Lago Tefé, at confluence with Rio Amazon, Brazil.

Hydrops martii (Wagler, 1824)

Elaps Martii Wagler 1824. Type locality: Provincia Maranhao, Rio Itapicuru, Brazil
Hydrops Martii — Wagler 1830: 170
Homalopsis Martii — Schlegel 1837: 356
Hydrops callostictus Günther 1868: 421
Calopisma martii — Jan and Sordelli 1868
Hydrops triangularis martii — Amaral 1930
Hydrops martii — Dowling 2002

Distribution: Distribution: Amazon basin from Colombia and eastern Peru to Maranhao, Brazil. Known from tributaries of Rio Amazonas, the Rio Ucayali and Rio Marañon, Peru. Roze (1957) reported a specimen from Rio Cairary, near Jurupary waterfall, on the boundary between Colombia and Brazil. Type locality: Provincia Maranhao, Rio Itapicuru, Brazil.