Wednesday, May 23, 2018

[Herpetology • 2018] Anomaloglossus meansi • A New Pantepui Species of the Anomaloglossus beebei Group (Anura, Aromobatidae)

Anomaloglossus meansi 
Kok, Nicolaï, Lathrop & MacCulloch, 2018

Recent extinctions and drastic population declines have been documented in the Guiana Shield endemic frog genus Anomaloglossus, hence the importance to resolve its alpha-taxonomy. Based on molecular phylogenies, the literature has long reported the occurrence of an undescribed species in the Pakaraima Mountains of Guyana in the Pantepui region. We here describe this new taxon and demonstrate that in addition to divergence at the molecular level the new species differs from congeners by a unique combination of morphological characters, notably a small size (maximum SVL in males 18.86 mm, maximum SVL in females 21.26 mm), Finger I = Finger II when fingers adpressed, Finger III swollen in breeding males, fringes on fingers absent, toes basally webbed but lacking fringes, in life presence of a thin dorsolateral stripe from tip of snout to tip of urostyle, and a black throat in preserved males (immaculate cream in females). Virtually nothing is known about the ecology of the new species. We suggest the new species to be considered as Data Deficient according to IUCN standards.

Keywords: Aromobatidae, diversity, Guiana Shield, Guyana, Pakaraima Mountains

Anomaloglossus meansi sp. n. in life.
A female paratype ROM 43332, dorsal view B female paratype ROM 43329, dorsolateral view C male paratype CPI 11000, dorsolateral view. Photographs (A, B) by AL; photograph (C) courtesy D. Bruce Means. 

Anomaloglossus meansi sp. n.

Anomaloglossus sp. Ayanganna Grant et al. 2006: 120–121, 2017: S66.
Anomaloglossus cf. praderioi Kok 2010: 66.
Anomaloglossus sp. B Kok et al. 2012: supplementary information.

Diagnosis: The following characteristics pertain to preserved specimens unless otherwise noted. A medium-sized Anomaloglossus differing from other species in the genus by the following combination of characters: (1) mean SVL in males 18.53 mm (18.15–18.86 mm, n = 3), mean SVL in females 19.15 mm (17.66–21.26, n = 5); (2) skin on dorsum shagreened, venter smooth; (3) tympanic annulus visible anteroventrally; (4) Fingers I and II subequal in length, FI = FII when fingers adpressed; (5) tip of Finger IV not surpassing the base of the distal subarticular tubercle on Finger III when fingers adpressed; (6) distal subarticular tubercle on Finger III and IV present; (7) Finger III swollen in males (conspicuous pre- and postaxial swelling in breeding males); (8) fringes on fingers absent; (9) toes basally webbed, fringes on toes absent; (10) tarsal keel well defined, slightly tubercle-like and weakly curved at proximal end; (11) black arm gland absent, glandular supracarpal pad present in both sexes (larger and more glandular in males); (12) cloacal tubercles absent; (13) pale paracloacal mark present; (14) in life, thin dorsolateral stripe present, from tip of snout to tip of urostyle (not visible, or only barely distinguishable in preservative); (15) ventrolateral stripe absent, but presence of irregular white blotches on the lower flank; (16) oblique lateral stripe absent; (17) sexual dichromatism in throat colour pattern: throat heavily pigmented with melanophores in males (dark brown to black in life), immaculate cream in females (yellowish-orange in life); (18) sexual dichromatism in ventral colour pattern: belly pigmented with melanophores in males, immaculate cream in females; (19) in life, iris metallic reddish bronze with fine dark brown reticulation; (20) large intestine extensively pigmented; (21) testes cream, unpigmented; (22) mature oocytes partly pigmented; (23) median lingual process small, longer than wide, tapered; (24) maxillary teeth present, small.

Figure 4. Anomaloglossus meansi sp. n. in life.
A female paratype ROM 43332, dorsal view B female paratype ROM 43329, dorsolateral view C male paratype CPI 11000, dorsolateral view.
Photographs (A, B) by AL; photograph (C) courtesy D. Bruce Means. 

Figure 5. Habitat of Anomaloglossus meansi sp. n. on the Wokomung Massif
A photograph (looking NE) of the highest part of the massif; the plateau in the centre of the photo is the tallest part of the entire Wokomung Massif
B cloud forest at about 1385 m elevation, habitat of Anomaloglossus meansi sp. n.
Photographs courtesy D. Bruce Means.

Distribution and natural history: The only localities documented for the new species are depicted in Figure 2. Specimens were collected in cloud forest (Figure 5), on the ground or low vegetation. Most were collected after nightfall, although one adult and one juvenile were collected during daylight. Specimens were collected on mountain flanks, not summits; at 1490 m on Ayanganna, and at 1234 m, 1371 m and 1411 m on Wokomung. The majority of specimens (eight) were collected at 1234 m on Wokomung. Fewer were collected at higher elevations; only one each at 1490 m on Ayanganna, 1371 m and 1411 m on Wokomung. This may have been because of habitat differences; high-canopy open forest at lower elevation and dense, low-canopy vegetation at higher elevations.

Etymology: It is a great pleasure to name this new species after our friend and colleague D. Bruce Means, indefatigable explorer of the “islands in the sky”, and who collected one specimen of the new species and contributed with photographs and data. Thanks to his extensive fieldwork, Bruce Means greatly contributed to our understanding of the distribution, ecology, and taxonomy of Pantepui amphibians and reptiles. The specific epithet should be treated as a noun in the genitive case.

 Philippe J.R. Kok, Michaël P.J. Nicolaï, Amy Lathrop and Ross D. MacCulloch. 2018.  Anomaloglossus meansi sp. n., A New Pantepui Species of the Anomaloglossus beebei Group (Anura, Aromobatidae). ZooKeys. 759: 99-116.  DOI: 10.3897/zookeys.759.24742