Additional evidence for Phyllomedusa trinitatus being distinct from P. tarsius

Phyllomedusa trinitatis. JCM

The Tarsier Leaf Frog (family Phyllomedusidae), was described as Pithecopus tarsius by Cope in 1868. It is found in Brazil, Colombia, Ecuador, Peru, and Venezuela, and possibly Bolivia and Guyana. Its natural habitats are subtropical or tropical moist lowland forests, subtropical or tropical swamps, intermittent freshwater marshes, and heavily degraded former forest.

Mertens (1926) described Phyllomedusa trinitatis from Port of Spain, Trinidad and Phyllomedusa venusta was described by Duellman and Trueb (1967) from Darién Province, Panamá.

Barrio-Amorós (2009) doubted the distinctiveness of Phyllomedusa venusta from P. trinitatis, and also reidentified specimens identified as Phyllomedusa tarsius from along the Guyana border as P. trinitatis. This suggests  Phyllomedusa trinitatis likely extends into Guyana, and the records of Phyllomedusa tarsius from Guyana need re-examination.

A forthcoming paper by Mechkarska et al. (2018) examined peptidomic analysis of norepinephrine-stimulated skin secretions from the Trinidadian Leaf Frog and found 26 host-defense peptides. The primary structures of the peptides support the claim that P. trinitatis and P. tarsius are very closely related phylogenetically but are probably not conspecific as suggested by Duellman (1974).

Left: Phyllomedusa tarsius by Jean-Marc Hero. Right Phyllomeusa venusta
by Mauricio Rivera Correa

References

Barrio-Amorós CL. 2009. Distribución y aspectos de la historia natural de las ranas lémur (Hylidae: Phyllomedusinae) en Venezuela. Memoria de la Fundación La Salle de Ciencias Naturales. Caracas 171: 19–46.

Cope ED. 1868. An examination of the Reptilia and Batrachia obtained by the Orton Expedition to Equador and the Upper Amazon, with notes on other species. Proceedings of the Academy of Natural Sciences of Philadelphia 20:96–140.

Duellman WE. 1974. Taxonomic notes on Phyllomedusa (Anura: Hylidae) from the upper Amazon basin. Herpetologica  1:105-12.

Duellman WE, Trueb L. 1967. Two new species of tree frogs (genus Phyllomedusa) from Panamá. Copeia 1967:125–131.

Mechkarska M, Coquet L, Leprince J, Auguste RJ, Jouenne T, Mangoni ML, Conlon JM. 2018. Peptidomic analysis of the host-defense peptides in skin secretions of the Trinidadian leaf frog Phyllomedusa trinitatis (Phyllomedusidae). Comparative Biochemistry and Physiology Part D: Genomics and Proteomics. 2018 Dec 1;28:72-9.

Mertens R. 1926. Herpetologischen Mitteilungen VIII–XV. Senckenbergiana Biologica 8: 137–155.

Tadpoles of the Tobago Glass Frog

A metamorph of the Tobago Glass Frog.

The Tobago glass frog, Hyalinobatrachium orientale tobagoense is endemic to the island of Tobago. They reproduce by laying a clutch of gelatinous eggs on the underside of broad leaves overhanging streams, a mode of reproduction which is characteristic of all Hyalinobatrachium. The embryos develop on the leaf until hatching when they drop into the stream below where they develop further, eventually emerging as metamorphs.

Previous authors have reported on embryonic development, hatching, and tadpole growth and morphology in this frog. The tads initially lacking pigmentation, but with age develop pigment over much of the body, darker on the dorsal side, but lacking on the tail fins and ventral body. The tadpoles’ eyes are small and dorsally oriented.  They have very long tails, 64% of total length. In the lab, growth, is very slow. After six weeks, tadpoles had tripled in mass, increased in length by a little under 40%, but were still at Gosner stage 25, with no sign of limb buds. Previous authors have reported very slow growth and development in two glass frog species which took more than  200 days to reach metamorphosis.

Tadpoles hide in sediment and among rocks, gravel, and fallen leaves, and escape with bursts of fast swimming when disturbed. Given their secretive nature, it is not surprising that the behavior of these tadpoles is poorly known.

In a recent paper, Byrne et al. (2018) collected egg clutches of the Tobago Glass Frog and allowed them to hatch into tanks of native stream water.  Observations were made through a series of tests for substrate preference (gravel, rocks or leaves), shelter or open water preference, and surfacing behavior under different depths and turbulence levels. Tests found that tadpoles showed a preference for stream substrates over plastic tank floor, with the highest percentage of tadpoles found in gravel. Tadpoles preferred sheltered areas of the tank and surfaced significantly less when water was turbulent, with depth having no significant effect on surfacing behavior.

Byrne I, Judge C, Downie JR. 2018. The behaviour of recently hatched Tobago glass frog tadpoles. Herpetological Bulletin. 2018 Jun 1(144).

Brazilian Bent-toed Gecko, Gymnodactylus geckoides Spix

Bent-toed Gecko, Gymnodactylus geckoides is listed here on the basis of a single museum specimen. It is not likely part of the current fauna. If this genus is present on Trinidad, it can be identified by the presence of free fingers that are not expanded; the fingers have wide, undivided sub-digital lamellae; the distal phalanges are elevated above the basal ones; the nail or claw is placed between two scales with the ventral scale indented; straight, vertical pupils and dorsal scales are a mixture of granules and tubercles. This lizard is otherwise known from Brazil; its presence on Trinidad is problematic.

The only known specimen (FMNH 177679) of Gymnodactylus gekkoides supposedly collected in Trinidad's Arima Valley in 1962 by Edward Taylor. 

Anolis sagrei (Duméril and Bibron, 1837) Introduced

Anolis sagrei has apparently been introduced into Port-of-Spain, Trinidad

A Brown Anole, Anolis sagrei, photographed in southern Florida. JCM

Size. Males to 70 mm, females 48 mm; hatchlings 16 mm SVL. Smallest sexually mature male 35 mm, female 34 mm.

Identification. Brown to gray, with white or yellow patterning on the back. Dewlap orange or red with a white or yellow edge. Scales between the supraorbitals are variable ranging from none to several; scales separate the interparietal and supraorbital from the semicircles scales. Head scales keeled; five postrostrals; two postmentals. Mid dorsum has six rows of slightly enlarged scales; tail laterally compressed and may have a slight crest; keeled ventral scales that are pointed posteriorly.
Similar species. All Trinidad and Tobago anoles have cycloid (rounded) ventral scales with the exception of Anolis planiceps. Anolis sagrei has the subocular scales in contact with the upper labials. Anolis planiceps has the subocular scales and the upper labials separated by a row of scales. Anolis tigrinus has no enlarged mid-dorsal scales. Polychrus has femoral pores but all anoles lack them.

Distribution. This species has five currently recognized subspecies. Which one was introduced on Trinidad is unknown. The species is widespread in the Lesser Antilles and has been introduced into the USA (California, Florida, Texas, and Hawaii), Mexico, Belize, Aruba, and Taiwan. In Trinidad it is known only from the heart of Port of Spain, suggesting it may have arrived with ornamental plants.

Habitat. A ground dweller but will climb into low vegetation; this species thrives in almost all man-made habitats and they are abundant in suburban and urban environments.


Biology. Diurnal. Basks and forages on the ground and in vegetation. The diet includes insects, spiders, and other invertebrates (mites, isopods, gastropods). Females lay a single egg in moist soil or rotten wood at about 14-day intervals.

Guyana Dawn Blind Snake, Typhlophis squamosus Schlegel 1839

Typhlophis squamosus Schlegel 1839 in Error

Guyana Dawn Blind Snake, Typhlophis squamosus, has been reported in the literature as present in Trinidad. We have not been able to document its presence with a specimen. However, this has not stopped some authors from applying the common name “Trinidad Blind Snake” and even Wikipedia claims it is on Trinidad. We would like to see the evidence. Dorsal scales in 24 rows around mid-body, counted longitudinally the dorsals number 340−377; upper labials 4, lower labials 3; nostrils separated from the rostral by a single scale; tail ends in a sharply pointed scale. The dorsum and venter are dark brown, the head is pinkish cream, and the tail tip is brown. The known distribution is in Guyana and Brazil.

Red Whipsnake, Chironous scurrulus In Error

Red Whipsnake, Chironous scurrulus (Wagler). We have previously discussed this species and the evidence that suggests it is not part of the Trinidad fauna. Go to this post

Klauber's Threadsnake, Epictia tenella (Klauber, 1939)

Klauber's Threadsnake, Epictia tenella (Klauber, 1939)

Previously known as Leptotyphlops albifrons.

Size. 275 mm TL, tail very short about 6–7% of total length.

Identification. A small, silvery, striped snake with a yellow face and yellow tail; each scale row has a dark stripe. Head no wider than neck; rostral visible from above; nasals extend to border of mouth and separate two labials; no loreal; ocular scale contains a relatively large eye that nearly touches the anterior edge of the scale; two upper labials, the first upper labial contacts the supraocular; four lower labials; 219–229 ventrals; 15–20 subcaudals; 14 rows of smooth dorsal scales; tail ends in sharp spine; ventrals about as wide as dorsals.

Similar species. The supraocular and first labial in contact, and a pentagonal-shaped ocular scale separates it from all other Trinidad snakes.

Distribution. Epictia tenella occurs on Trinidad, Venezuela, and northern Brazil. Habitat. A fossorial snake found in urban gardens, savanna, and forest. It climbs on rock walls and tree trunks to reach food sources but is most often found under rocks, logs, and in leaf litter near ant and termite nests.
Biology. Active any time of day. This is an ant and termite specialists which locates colonies by following the chemical trails laid down by the social insects. This is the most frequently encountered species of Trinidad scolecophidian snakes.

Chacachacare Thread Snake, Epictia cf. fallax

Chacachacare Thread Snake
Epictia cf. fallax

Previously known as Leptotyphlops goudotii

Size. 160 mm in total length.

Identification. An Epictia that is extremely gracile, body shape (total length/diameter at mid-body) is 72.7 mm. The tail is 4.3% of the total length. The rostral scale extends between the eyes.

Similar Species.  Most easily confused with Klauber’s Threadsnake which has a body shape that is 51–62. and has a supraocular longer than frontal. The interoccipital scale s distinct from dorsals (it is not in E. tenella).  The body shape, combined with a tail that is 4.3% of the total length, and a rostral scale that extends between the eyes separate this snake from all other Epictia found in northern South America.

Distribution. Known only from Chacachacare Island.

Neotropical Blind Snake, Amerotyphlops cf brongersmianus

Neotropical Blind Snake, Amerotyphlops cf brongersmianus 


Size. 325 mm TL, tail about 2.1% SVL.
Identification. Cigar-shaped body and a uniform brown colour distinguish it from A. trinitatis, which has a striped pattern with yellow blotches at each end. Three light spots on the head, a large central spot and a smaller one on each side; eleven dorsal scale rows with yellow-brown or red-brown pigment, snout may be streaked with dark brown that forms fan-shaped spots; nine ventral scale rows are yellow or pink. Rostral visible from above; nasals large and semi-divided; four upper labials; eyes distinct but under ocular shields; scales around body number 20, reduce to 19 or 18 posteriorly; dorsal scales from rostral to tail-spine range from 195 to 287 (average 233.1). Trinidad population and some mainland populations to south and east are characterized by low numbers of dorsals; subcaudals 8-14 (average 10.6); tail wider than long, ending in a conical spine.

Similar species. The two species of Epictia have 14 rows of scales around the body, and the Helminthophis has 18 rows of scales around the body; it can be readily distinguished from Amerotyphlops trinitatis by its uniform brown dorsal pattern; A trinitatus is striped.
Distribution. On Trinidad it is known only from Tucker Valley and Aripo Savanna. Elsewhere, it may be present on the Guiana Shield. It is likely this widespread species is composed of multiple cryptic taxa.

Habitat. Rainforest leaf litter and soil.

Biology. Probably nocturnal, very secretive. Diet: Probably includes ants and termites.  Some specimens of Amphisbaena gracilis and A. brongersmianus were found among the leaves of a Moriche palm (Mauritia flexuosa) in a flooded morichal in the Orinoco Delta. These specimens tried to hide under dry leaves and, if this was not possible, they jumped directly into the water.

Trinidad Blindsnakes, Amerotyphlops trinitatus Richmnond

Trinidad Blindsnakes, Amerotyphlops trinitatus Richmnond

Size. 237 mm SVL, total length 240 mm. Tail about 1.2% of SVL.

Note similarity between head and tail.

Identification. Rostral visible from above; snout projects over the mouth; nasals divided; no loreal; a single small preocular contacts upper labials 2–3; four upper labials; third and fourth labials similar in size, both taller than long; ocular scale small; dorsal scales from rostral to tail-spine number 388–389; subcaudals in 10 rows; 20 scale rows around mid-body; dorsal pattern of 11–13 dark brown stripes; the yellow head and tail spots make it difficult to distinguish one end from the other.

Similar Species: Epictia tenella has 14 scales around the body. Ameroyphlops cf. brongersmianus has a larger diameter body, the pattern is uniform, not striped, and it has a complete nasal cleft. The undescribed anomalepidid also has a yellow-tipped head and tail, but has 18 scale rows at mid-body.
Distribution. Trinidad and Tobago.

Habitat. A forest and forest-edge species likely to be found in rotting logs, leaf litter, and loose soil. This species has been listed as critically endangered because many of its known locations are under or near development projects. However, it has been recently found in the Main Ridge Forest Reserve on Tobago. It is associated with Three-lined Snake and Hex-scaled Bachia in ant and termites nest associated with decomposing logs and vegetation.

Pair in copula.

Biology. Active any time of day. The diet includes ants and termites. We observed copulation in June and one female contained seven or eight eggs.

Tiger Rat Snake, Spilotes pullatus

Other common names: Tigre, El Tigre.

Size. Adult males larger than females. Average size is about 1,700 mm SVL, 2,311 mm TL, may exceed 3.6 m; hatchlings average 376 mm SVL; tail about 32% of SVL.

A Tobago specimen. JCM

Identification. A large black and yellow snake with 16 or 18 rows of keeled dorsal scales that are reduced to 10 rows posteriorly. Yellow or white colouration is restricted to the anterior portion of the body. Tobago specimens tend to be darker than Trinidad and mainland specimens. Rostral visible from above; nasals semi-divided or divided; loreal single; one or two preocular; one or two postoculars;  six to eight upper labials, six to eight lower labials; ventrals 209−226; single cloacal plate; divided subcaudals 116−129; dorsal scales smooth in first two rows, other rows keeled. 

Similar species. Perhaps most easily confused with Spilotes sulphureus which has 21 dorsal scale rows and much more yellow in the dorsal pattern. Clelia is a solid blue-black as an adult with 19 scale rows at mid-body and a much shorter tail (62−76 subcaudals).

Distribution. Widespread, ranging from Mexico southward to Argentina; present on both Trinidad and Tobago. Many more specimens of this snake have been found on Tobago than on Trinidad. Tobago specimens occur from the highest forests down to littoral forests adjacent to the beaches. A specimen recently found at Cedros, Trinidad suggests the species is found island wide.
Habitat. Forested and forest-edge environments. It is arboreal but will come to the ground and use open habitats.

Biology. Diurnal. The diet includes birds and their eggs, but small mammals including bats, rodents, and the invasive mongoose are killed by constriction. The diet suggests the Tiger Rat Snake is an active forager and often a nest predator.

Male Spilotes pullatus engage in ritualized combat, a behaviour that has been reported in many other snake species. This behaviour may be used to maintain a territory or settle a dispute over access to a female. The male snakes partially entwine their bodies during combat and attempt to keep the head upright and above the other male. During the combat ritual, the snakes use their tails to restrain their opponent by preventing the opponent from moving forward. Biting during combat has not been observed in this species.  The bouts may last for more than an hour. Reproduction: Seasonal reproduction is likely at higher and lower latitudes, with year-round reproduction likely at middle latitudes. Egg-laying has been reported in early summer, hatchlings found in early July. Clutch sizes of 5-11 eggs reported.

Defensive behaviour includes inflating the forebody with the trachea, loud hissing, and tail vibration. The bottom photo in plate 145 shows the defensive behaviour  that expands the forebody and exposes the skin between the scales. This behaviour is shared with the Yellow-bellied Puffing Snake. The unusual behaviour of kinking or bending the

Erythrolamprus sp Tobago

Previously known as Liophis reginae ssp.

Size. 362 mm SVL, 120 mm tail; tail 33.1% SVL.

Identification. Rostral visible from above; eight upper labials; 9−10 lower labials; fourth and fifth upper labials enter the orbit; two primary and one secondary temporals; one preocular; two postoculars; a divided anal plate. Dorsal scales are in 17 rows at mid-body and reduced to 15 posteriorly; 143-146 ventrals; 66-77 subcaudals; upper labials are eight or nine, and there are eleven lower labials. The posterior ventral surface has some light mottling.

Distribution. This undescribed species is known from northeastern Tobago, and likely to be endemic. However, its eventual discovery in Venezuela cannot be ruled out. It is currently known from five specimens. Habitat. Primary and old-growth secondary forest. One specimen was found on a steep slope above a stream.

Biology. Diurnal. It is likely to be closely related to E. zweifeli and E. reginae from the Guiana Shield and have habits similar to those two species.