Sunday, April 1, 2018

Barbados Anole, Anolis extremus (Family Dactyloidae)

Anolis roquet var. extremus Garman 1887: 35
Anolis extremus — Schwartz & Henderson 1991: 262

Distribution. The Barbados anole (Anolis extremus) is native to Barbados, but introduced to Saint Lucia and Bermuda, Trinidad and Huevos I. It does not appear to have survived the introductions on  Huevos. However, it is present on the grounds of Piarco Airport.

Diagnosis. Males have pale lavender to blue-gray heads, with blue eyelids. Their body is a deep green with dark markings and occasionally white spots, and ventral surfaces are yellow. Females are smaller and duller in color and may have a mid-dorsal stripe. Photo by Postdif.

Creer, D. A., Queiroz K., Jackman TR, Losos JB, Larson A. 2001. Systematics of the Anolis roquet series of the southern Lesser Antilles. Journal of Herpetology 35 (3): 428-441

Garman, S. 1887. On West Indian reptiles. Iguanidae. Bull. Essex Inst. 19: 25-50.

Lazell, J.D. 1972. The anoles (Sauria: Iguanidae) of the Lesser Antilles. Bull. Mus. comp. Zool. Harvard 143 (1): 1-115.

Schwartz, A. & Henderson, R.W. 1991. Amphibians and Reptiles of the West Indies. University of Florida Press, Gainesville, 720 pp.

Tuesday, March 13, 2018

Diversity of Amphibians at the Aripo Savannas, Trinidad, WI

Leptodactylus fuscus

Information on amphibian diversity in Neotropical savannas and in protected areas in the Caribbean is lacking. We evaluated amphibian diversity and species composition in the Aripo Savannas Scientific Reserve in Trinidad, in relation to the two major habitat types, savanna, and marsh forest. Auguste and Hailey (2018) surveyed thirty 200-m-long transects were sampled visually and aurally in 4 periods (total 120 samples), with 10 transects in savanna, and 20 in marsh forest (10 along trails and 10 off trails), at night in the wet season from June to December 2015. We recorded 895 individuals representing 16 species, 11 genera, and 7 families, with greater counts and diversity of amphibians in marsh forest compared to savanna. The three species recorded in the savanna (Leptodactylus fuscus, Scinax ruber, and Rhinella beebei) were also found in marsh forest, with no separate savanna amphibian community. Audio detection was more effective at sampling most species, and there were greater counts along trails compared to transects off trails.

Auguste RJ, Hailey A. 2018. Diversity and Species Composition of Amphibians of the Aripo Savannas Scientific Reserve, Trinidad, West Indies. Journal of Herpetology. 52(1):86-93.

Monday, August 21, 2017

Hunter Destroy Trinidad's Caroni Swamp Scarlet Ibis Population

There are two serious threats to wildlife across the globe: habitat loss and market hunting. As the human population expands towards eight billion humans hunting becomes a serious threat to the survival of many species. This is particularly true in the tropics where the productivity of edible wildlife is low.Removing large numbers of animals via hunting or any other method impacts the entire biotic community - often in unexpected ways. The loss of the Caroni Scarlet Ibis populations is deeply disturbing not because it generated a considerable number of tourism dollars, but the population was a symbol of Trinidad wildlife. The people who did this need to be publically exposed and shamed; and law enforcement needs to take action against them, no matter how politically incorrect it may be in certain segments of the population. The fact that bushmeat is popular in 2017 Trinidad say much about the society and the need for conservation education.  The only question is what species will be the next to go?


Sunday, July 9, 2017

Small headed Treefrog, Dendropsophus microcephalus

Hyla microcephala Cope, 1886:281. Syntypes: USNM 13473 (2 specimens), presumed lost.

Hyla microcephala Boulenger, 1898, Proc. Zool. Soc. London, 1898: 481.

Hyla misera Werner, 1903, Zool. Anz., 26: 252. Holotype: IRSNB 4549. Type locality: "Caracas, Venezuela". Synonym by Fouquette, 1968, Herpetologica, 24: 324.

Hyla misera ― Lutz, 1927:66.

Hyla microcephala misera Fouquette, 1968:324. Type locality: “…17 km NE of Acarigu, Portuguesa….” Venzuela.

Hyla miisera [sic] MacLean, et al. 1977:45

Dendropsophus microcephala ― Faivovich et al. 2005:92

Dendropsophus microcephala misera ― Faivovich, et al. 2005:92

A small yellow frog: 12-17 mm SVL; with the canthus forming a distinct ridge, and a light line from the anterior of eye to nostril. Dorsal skin smooth, ventral skin and skin under are thighs granular. Fingers with some webbing mostly reduced to bases of digits and lateral fringe; toes moderately webbed. H.goughi has a rounded canthus and lacks a lateral cream or enamel stripe. To distinguish it from H. m. misera: both species have a canthal ridge, but H. minuscula is much smaller, calling males tan and red, with side stripe that makes this species unique, and readily identified in the field.

Size. A small tree frog: males are typically 18-25 mm SVL (mean: 22 mm) and females 21-28 mm SVL (mean: 25 mm).

Identification. Dorsal skin smooth and variable in color, ranging from pale yellow and orange-brown. Venter is white, with distinct tubercular skin on the belly and thighs, which are used as complementary adhesive surfaces. Tubercles on the ventral thigh are yellow.  Reproductively active males have a yellow throat pouch and, when calling, are solid yellow in color. Dorsal markings are variable, often consisting of a network of darker brown speckled lines giving a ‘marbled’ appearance or creating an H-shaped marking between the shoulders. A dark interorbital line or blotch is common. A narrow brown line extends laterally from the nostrils, along with the canthal ridge, over the eye to midway down the body. This gives the frog’s head a distinctive triangular appearance. Dark brown flecks are scattered across the dorsum, the forelimbs and the lower hind limbs, with these forming two to three indistinct transverse bars on the shin in many individuals. Thighs are translucent and yellow with no pigmentation. Eyes are prominent, with a bronze iris and horizontally elliptical pupils. Eye diameter is generally greater than or equal to the eye-nostril distance. The tympanum is distinct and speckled with gold flecks. Webbing on the fingers is reduced, toes have moderate webbing. Fingers and toe tips are yellow, with expanded discs to aid with climbing at the ends of the digits. The feet have prominent subarticular tubercles, which are yellowish in color. 

Vocalization. Males call from marginal vegetation, emergent grasses and shrubs, usually at heights of 20-50 cm above the water. Dendropsophus microcephalus call in large assemblages, often with multiple species present (including D. goughi, D. minusculus, L. validus, S. ruber, H. punctatus, P. trinitatis and S. lacteus).  The call is a high-pitched “skrreeet, riti-titi-titi-titi” with the last phase of the call having an almost sawing rhythm.

Similar species. Small-headed Treefrog is one of three closely related frogs found in Trinidad (see also D. goughi and D. minusculus) all of which are small and yellowish in color. Dendropsophus microcephalus has a distinct pale line that runs from the back of each eye to just over the nostril, which makes the head appear almost pointed in shape. Dendropsophus minusculus is smaller as an adult, and has an enamel colored lateral stripe. The belly of Dendropsophus goughi is yellow rather than white, it has white markings on the rump and heels, and a rounded canthus all are absent in the other two dendropsophids. See the other species descriptions for comparison. 

Biology. Diet includes ants, spiders, ticks and mites. Arachnids are a particularly important element of their diet and can comprise over 80% of prey. Soil organisms, such as collembolans are a significant prey item for the wet season. Adults and tadpoles are vulnerable to predation by a wide range of both vertebrate and invertebrate predators, including snakes, (Leptophis), large spiders, and water bugs. Crabs are thought to be significant predators of both the adult frogs and their eggs in Trinidad. Dendropsophus microcephala is an opportunist breeder, with reproductive activity triggered by significantly increased rainfall. In Trinidad, males have been recorded calling throughout the rainy season with peaks in activity in June-July. Frogs can be found calling in mixed-species choruses, in the north of Trinidad, particularly alongside D. microcephalus which often outnumbers them significantly. In Trinidad, calling males are often attended by silent satellite males which attempt to intercept females attracted to the breeding ponds. 
Distribution. Widely distributed in Middle and South America and has been recorded from Mexico, Guatemala, Honduras, Nicaragua, Costa Rica, Panama, Colombia and Venezuela as well as from Trinidad and Tobago. The island subspecies is D. microcephalus misera, and is also known from the llanos of Colombia and Venezuela. In Trinidad, D. microcephalus is found island wide, at low elevation sites ranging from the southwestern peninsula to Chaguaramas. On Tobago, it occurs at scattered localities but widespread.

Habitat. The Small-headed Treefrog is highly adaptable and is often found in disturbed habitats, forest edges, and savanna habitats. Breeding sites include temporary ponds, shallow roadside ditches, and flooded pasture land as well as swamps and marshes. They are rarely recorded from more enclosed, forest habitat.    

Biology.  Nocturnal, but can be found during the day close to their calling sites, concealed in vegetation. Diet consists of small flies, spiders, and cockroaches. Dendropsophids fall prey to a wide range of predators including bats, snakes, other frogs and large invertebrates such as water bugs, fishing spiders, and centipedes. 

Calling can be heard throughout the year as long as water is available. Studies in Colombia and Venezuela suggest that D. microcephalus is an opportunistic breeder, with activity increasing during and after rainfall. Eggs are laid on or near the surface of the water, usually attached to emergent vegetation. Spawn is present as a small cohesive mass, with each dark-colored egg within its own jelly capsule. Reported clutch sizes range from 150-400 eggs, though clutches of around 200 eggs are more typical for Trinidad. 

Tadpoles are tiny and black-brown when they first hatch. Later stage tadpoles are distinctive, and colorful in appearance with a silver-white belly flecked with black, a yellow-brown dorsum and tail, which are mottled and marbled with black. The tail is deep and leaf-shaped and tapers off to a distinct filament, which is barred with black bands. A dark-brown stripe runs from the nose through the eye and along the side of the tadpole’s body. Tadpoles are filter-feeders and are often observed in open water, hanging vertically and maintaining their position by rotational movements of the filamentous tail tip. Development is rapid, with metamorphosis occurring at about six weeks. Maximum lengths are around 35 mm. Newly metamorphosed froglets are about 10 mm SVL.

Conservation status. Least Concern. Data suggests it is both abundant and increasing in numbers. Taxonomic status of subspecies needs clarification. It is less susceptible to chytridiomycosis than many other species. There is some suggestion, therefore, that it might act as a ‘reservoir taxa’ and it may be important to consider the nature of interactions that might occur in mixed species assemblages at breeding sites.

The Paradox Frog, Pseudis paradoxa (Family Hylidae)

Nariva Swamp, JCM

Rana paradoxa Linnaeus, 1758, Syst. Nat., Ed. 10, 1: 212. Syntypes: Animals figured by Seba, 1734, Locuplet. Rer. Nat. Thesaur. Descript. Icon. Exp. Univ. Phys. Hist., 1: pl. 78, by original designation, and NHRM 144-148, according to Duellman, 1977, Das Tierreich, 95: 199. Type locality: "Surinami".

Pseudis merianea ― Court, 1858:441.

Pseudis paradoxus ― Parker,1933:10.

Pseudis paradoxus caribensis Gallardo, 1961: 116. 
Type locality:"Mayaro Bay, Trinidad, B.W.I."

Pseudis paradoxa caribensis ― La Marca, 1992:75.

Pseudis paradoxa caribensis Gallardo is now placed in the Hylidae following Faivovich et al. 2005. Formerly this frog was placed in the family Pseudidae.

Adults are 45-75mm in total length. Body is short and stout; eyes dorsolateral; dorsal and ventral skin; fingers free of webbing, toes heavily webbed. Dorsum green anteriorly, brown to green posteriorly; flash marks on the posterior surface of the femur. Ventral immaculate white. Pseudis paradoxa has the largest, or near largest tadpoles known when compared to adult size. Tadpoles are 220 mm (3 to 4 times longer than adult frogs). As currently defined it is known from the following countries: Argentina, Bolivia, Brazil, Colombia, French Guiana, Guyana, Paraguay, Peru, Suriname, Trinidad (unknown from Tobago), and Venezuela. Usually found in open marshy areas with floating vegetation, in permanent and temporary ponds. Calls can be heard day and night and consist of a sequence of 8-11 pulses, but frogs are very wary during the day. At night they can be seen floating on the surface and grasping vegetation with their hands. Mating may be stimulated by rainfall. Eggs are green and laid along the shore among aquatic plants.

Tungara Frog, Engystomops pustulosus (Family Leiuperidae)

Paludicola pustulosa Cope, 1864: 180. Type locality: "New Grenada, on the River Truando," Colombia.

Eupemphix trinitatis ― Boulenger, 1889b:307.

Eupemphix puslulosus Boettger, 1892:40.

Bufo arriglaris ― Werner, 1899:482.

Eupemphix pustulosa ― Lutz, 1927:49.

Eupemphix pustulosus trinitatis: Parker, 1933:8.

Eupemphyx pustulosus ― Boos and Quesnel, 1968:39.
Physalaemus pustulosus ― Lynch, 1970:489.

Eupemphix pustulosus trinitatus [sic] MacLean, et at. 1977:45.

Physalaemus pustulosus trinitatis ― Harding, 1983:234.

Size: small terrestrial frogs, males 28 mm, females 32 mm SVL.

Identification: Dorsal skin highly tubercular, arranged more or less in longitudinal rows; lateral skin also tubercular. Dorsum brown-grey with darker spots along tubercle rows. Ventral skin granular, tan to yellow. Dorsal surface of hind limbs cross-barred. Snout pointed in dorsal view, rounded in profile. Tympanum indistinct.
The foam nest of the Tungara Frog. JCM
Small triangular parotoid gland present. All digits lack webbing and adhesive discs. Toes have a slight lateral fringe.

Similar species: The size, shape, wariness, and vocalizations of tungara frogs make them readily distinguishable.

Distribution and habitat: The genus Engystomops contains nine species, distributed from southern Mexico to northern South America and on to Bolivia.

Vocalization: There are two components to the call, a resonant ‘poong’ followed by a series of short ‘chucks’- ch,ch,ch. Complexity added by the chucks helps to attract females, but it also attracts predatory bats, so in the presence of bats, the male frogs simplify their calls.

Research indicates that the E. pustulosus is a very widespread species, from Mexico, south through Central America and Amazonia. 

Although there is considerable variation there is no firm basis to subdivide the population into different species. E. pustulosus is very common in both Trinidad and Tobago, mainly in lowland grasslands, forest fringes and in towns as a human commensal (often co-occurring with Leptodactylus fuscus).

Biology: Diet not reported. Mating pairs generate white floating foam nests, about 6-8 cm, in the open at the edges of ponds, choked ditches, even water-filled tire ruts. Each nest contains 300-500 creamy white eggs which hatch into the water below after about 2 days. 

Tadpoles are capable of metamorphosis after about three weeks, at which time they reach a maximum length of about 22 mm. Body rounded, tail tapered. Overall coloring pale gray/brown. These tadpoles are cryptically colored and tend to be found in the sediment at the bottom of temporary pools. Newly metamorphosed individuals are about 9 mm SVL and look like miniature adults.

Conservation status: Least Concern on account of its wide distribution, tolerance of a wide range of habitats, and presumed large population.

Knudsen’s Thin-toed Frog, Leptodactylus knudseni (Leptodactylidae)

Specimen from Suriname
Leptodactylus knudseni is widely distributed in the greater Amazon basin from Bolivia and Brazil north to Colombia, Venezuela, and the Guianas. Its presence on Trinidad is based upon a single specimenMCZ 8663. R. R. Mole collected or presented, the specimen to the MCZ, in May 1915. This species is in the pentadactylus Group and early references to Leptodactylus pentadactylus on Trinidad probably refer to this species. Barbour (1914) suggested that L. pentadactylus may have been exterminated on Trinidad because of its culinary value. The species presence on Trinidad has been reported only once in the early literature from the Island (Mole and Urich, 1894a) and they suggested it may have been exterminated by the introduction of the mongoose. Hardy (1982) suggested a member of the pentadactylus Group may also occur on Tobago, recounting Ober’s (1898) description of a gourmet frog dinner on Tobago and a subfossil frog femur from a cave. The presence of an extant population of this frog on either island is not substantiated in this work.

Suriname Toad, Pipa pipa (Family Pipidae)

Rana pipa Linnaeus, 1758:210. Type locality: Suriname.
Pipa americana ― Court, 1858:441.
Pipa pipa ― Barbour, 1923:3

Size: Large aquatic frogs, up to 200 mm SVL; sexual dimorphism not reported.

Identification: Dorsal skin dark brown/gray with many small dark brown tubercles which end in small sharp points; ventral skin paler. Head and body flattened and wide. Head almost triangular in shape with a short straight-ending snout; eyes very small; tympanum is hidden; mouth as wide as the head, no tongue. Forelimbs are long and slender, with long unwebbed fingers terminating in four small projections, each sub-divided. Hind limbs powerful, with wide feet, toes fully webbed. 

Vocalization: The call is said to be a subtle ‘click’ made underwater.

Similar species: Pipa pipa cannot be confused with any other species.

Distribution and habitat: The genus Pipa contains seven species inhabiting wetlands through much of South America. P. pipa is often known as the Suriname Toad, but outside the Guianas, the Pipa Toad is a more appropriate common name. P. pipa is found from Peru and Bolivia north to the Guianas and Trinidad, but not Tobago. Widely distributed in Trinidad at lower elevations in swamps and slow-moving turbid streams.

Biology: The habits of Pipa Toads have not been studied in the wild. In aquaria, adults sit motionless on the bottom, with their arms held forwards and wide apart; they capture fish very rapidly by opening the mouth wide and apparently shoveling the fish in using the arms. During mating, the fertilized eggs become individually embedded in the hormonally softened skin of the female’s back; each egg is covered by a thin capsule and develops there until around the stage of metamorphosis; the young emerge as fully metamorphosed miniature adults, or they may retain a short tail for a few days.
Tadpoles: If a free-swimming tadpole stage occurs, it is at Gosner stage 42 or later, with the tail regressing over a few days.

Conservation status: Least Concern on account of its abundance and wide distribution. Note that recent efforts to find this frog on Trinidad have not been successful.

Orinoco Crocodile, Crocodylus intermedius (Family Crocodylidae)

This species is listed here because it is a potential waif from the nearby Orinoco River. It is unlikely to be found in Trinidad or Tobago. Size. 6.8 m. Diagnosis. Snout elongated and pointed, adult individuals lack a pre-orbital hump present in C. acutus; the symphysis of the lower jaw extends to the sixth tooth in this species, but to the fourth or fifth tooth in C. acutus. It can be separated from the common caiman, Caiman crocodilus by having the fourth tooth in the lower jaw visible (it is not visible in the caiman) and it lacks the interorbital ridge present in caimans. Distribution is restricted to the Orinoco drainage of Colombia and Venezuela. It may occasionally show up as a waif on the shores of Trinidad and nearby islands, including Chacachacare Island and Grenada. Thus, there is no evidence that this species occurs on Trinidad or Tobago, but because the Orinoco species may occasionally wander down river to these islands, there is a possibility of its occurrence. Life History. During the wet season individuals may move great distances, but during the dry season, they restrict their activity to deep pools that remain in rivers. Juveniles use still water with dense vegetation. Females mature at 250 cm; nesting occurs early in the dry season and eggs hatch during the initial rise in water level at the start of the wet season; eggs are laid in a hole excavated in either an eroded river bank or a beach. Individual females are known to reuse nesting sites. Photo by Greg Hume.

The Neotropical Pipe Snake, Anilius scytale (Linnaeus 1758)

The Neotropical Pipe Snake, Anilius scytale, is discussed here because it was been reported from Trinidad as early as 1858. This species is in its own family, the Aniliidae and is generally considered to represent an ancient lineage of snakes, and it is one of only a few clades of snakes to retain teeth on the premaxillary bone, a trait considered to be primitive. It is ovoviviparous. The diet consists of elongated amphibians and other reptiles. The pipe snakes' body is cylindrical and uniform in diameter, the tail is exceptionally short, all characteristics of a specialized burrowing snake; the color pattern is red and black bands (no yellow or white bands); eyes are degenerate and embedded in large ocular scales. This species is found in Amazonian South America, Guyana and probably Trinidad. Total length is about 70 cm. The photograph is a museum specimen from Guyana. This species is probably not part of the Trinidad fauna.

Three-lined Snake, Atractus trilineatus (Family Dipsadidae)

Atractus trilineatus Wagler 1828
Rhabdosoma lineatum — Duméril & Bibron 1854: 105.
Rabdosoma trivirgatum Jan 1862.
Rabdosoma punctatovittatum Jan 1862.
Rabdosoma trivirgatum — Jan 1865.
Rabdosoma punctatovittatum — Jan 1865.
Rhabdosoma lineatum — Garman 1887: 280.

Syntypes: MNHN, now lost [Rabdosoma punctatovittatum]. Lectotype: RMNH 48, a 205 mm female, designated by Hoogmoed, 1982: 135. Type locality: Caracas, Distrito Federal, Venezuela.

Distribution. This is a lowland Guiana endemic known from northern Venezuela and the Guianas, and is present on both Trinidad and Tobago, and is known from the Bocas as well as Little Tobago.
Males are gray-brown, females are red.

Size. 350 mm SV L, 285 mm TL. Diagnosis. Snout and tail sharply pointed, dorsum brown-gray with three or four light lines; scales smooth in 15 rows at mid-body. Perhaps most easily confused with Atractus univittatus (only known from Tobago and main land Venezuela) which has 17 scale rows at midbody or Epictia tenella which has cycloid scales in 14 rows at mid-body.

Life history. A fossorial snake of forests and savannas as well as urban environments. Diet includes worms and insects. Reproduction. Females are known to lay 3–5 eggs, in March, May, and August suggesting it may reproduce year round. Defense behavior. The sharply pointed tail is used as a probe and can startle a potential predator. This snake is eaten by Erythrolamprus aesculapii and coral snakes.

Anonymous 2008. OPINION 2210 (Case 3365): Atractus Wagler, 1828 and Atractus trilineatus Wagler, 1828 (Reptilia, Serpentes): conserved. Bull. Zool. Nomencl. 65 (23):

Beebe, William 1946. Field notes on the snakes of Kartabo, British Guiana, and Caripito, Venezuela. Zoologica 31: 11-52

Boos, H.E.A. 2001. The snakes of Trinidad and Tobago. Texas A&M University Press, 270 pp.

Claessen, H. 2003. De slangen can de Guyana’s. Deel iv. Lacerta 61 (1): 19-27

Duméril, A.M.C., G. BIBRON & A.H.A. DUMÉRIL 1854. Erpétologie générale ou Histoire Naturelle complète des Reptiles. Vol. 7 (partie 1). Paris, xvi + 780 S.

Garman, S. 1887. On West Indian reptiles in the Museum of Comparative Zoology at Cambridge, Mass. Proc. Amer. Philos. Soc. 24: 278-286.

Gorzula, Stefan & Senaris, J. Celsa 1999. In: Contribution to the herpetofauna of the Venezuelan Guayana. I: a data base. Scientia Guaianae, Caracas, No. 8 [1998], 269+ pp.; ISBN 980-6020-48-0

Hoogmoed, M. S. 1982. Nomenclatural problems relating to Atractus trilineatus Wagler, 1828. Zoologische Mededelingen Leiden 56 (10): 131-138

Hoogmoed, M.S. & J.M. Savage 2006. CASE 3365: Atractus Wagler, 1828 and Atractus trilineatus Wagler, 1828 (Reptilia, Serpentes): proposed precedence over Brachyura Kuhl, 1820 and Brachyorrhos kuhli Boie in Schlegel, 1826. Bull. Zool. Nomencl. 63 (1)

Hoogmoed, M.S.; Savage, J.M. 2007. Case 3365. Atractus Wagler, 1828 and Atractus trilineatus Wagler, 1828 (Reptilia, Serpentes): proposed conservation. Bulletin of Zoological Nomenclature 64 (1): 60-63

Jan, G. 1865. Iconographie générale des ophidiens. 11. Livraison. J.B. Bailière et Fils, Paris

Johnson, M.L. 1946. Herpetological Notes from Trinidad. Copeia 1946 (2): 108

Lancini AR. & Kornacker PM. 1989. Die Schlangen von Venezuela. Armitano Editores C.A., Caracas, 1-381

Lynn, W.G. 1959. Some Reptiles and Amphibians From Trinidad. Herpetologica 15 (3): 113-117

Martins M. Oliveira M E. 1993. The snakes of the genus Atractus Wagler (Reptilia: Squamata: Colubridae) from the Manaus region, central Amazonia, Brazil. Zool. Meded. 67 (1-26): 21-40.

Mertens, R. 1972. Herpetofauna tobagana. Stuttgarter Beitr. zur Naturkunde nr. 252 22 pp.

Passos, P. & Fernandes, R. 2008. A new species of the colubrid snake genus Atractus (Reptilia: Serpentes) from the central Amazon of Brazil. Zootaxa 1849: 59–66

Passos, P., R. Fernandes and Borges-Nojosa, D.M. 2007. A New Species of Atractus (Serpentes: Dipsadinae) from a Relictual Forest in Northeastern Brazil. Copeia 2007 (4): 788–797

Passos P. Ramos LO, Pinna PH, Prudente ALC 2013. Morphological variation and affinities of the poorly known snake Atractus caxiuana (Serpentes: Dipsadidae). Zootaxa 3745 (1): 035–048

Passos, Paulo; Philippe J. R. Kok, Nelson R. de Albuquerque, and Gilson A. Rivas 2013. Groundsnakes of the Lost World: A Review of Atractus (Serpentes: Dipsadidae) from the Pantepui Region, Northern South America. Herpetological Monographs 27 (1): 52-86

Rivas, GA, Molina CR, Ugueto GN, Barros TR, Barrios- Amorós CL 2012. Reptiles of Venezuela: an updated and commented checklist. Zootaxa 3211: 1–64

Roze JA 1961. El genero Atractus (Serpentes: Colubridae) en Venezuela. Acta Biologica Venezuelica 3 (7): 103-119

Wagler,J. 1828. Auszüge aus seinem Systema Amphibiorum. Isis von Oken 21: 740-744