Bolitoglossa (Eladinea) diminuta

Arias, Erick, Chaves, Gerardo, Kubicki, Brian & Parra-Olea, Gabriela, 2024, Taxonomic assessment of the Bolitoglossa (Eladinea) subgenus (Caudata: Plethodontidae) with the description of two new species from the Cordillera de Talamanca, Costa Rica, Zootaxa 5537 (2), pp. 211-233 : 219

Bolitoglossa (Eladinea) diminuta Species Group

Our results show that the Bolitoglossa diminuta S.G. corresponds with the B. robinsoni species group of Kubicki & Arias (2016). The group contains seven species: B. aurae , B. aureogularis , B. diminuta , B. jugivagans , B. pygmaea , and two new species described here. The B. diminuta S.G. is distributed along the Talamanca Mountain range, at 1060–3300 m a.s.l. ( Fig. 1 ). The species B. aurae , B. aureogularis , and B. jugivagans are known only for the specimens described in the original description; no additional material is known.

Bolitoglossa diminuta : This species was described by Robinson (1976) based on an adult female (SL = 31.1 mm) from Tapantí, on the northern portion of the Talamanca Mountain range. The dorsal coloration of the holotype is brown with two lateral dark brown bands from the posterior margin of the eye to the anterior third of the tail. David Wake collected a second specimen (MVZ207052; photos in AmphibiaWeb) of this species in 1987, very near to the type locality, an adult female (SL = 31.5 mm). This second specimen agrees in dorsal coloration with the holotype; however, the holotype contrasts less in color between the dorsal and lateral areas. Both females were found brooding eggs. We found a third specimen (SL = 31.6 mm) in Tapantí, with a dorsal coloration pattern similar to Wake’s specimen ( Fig. 3D ). This specimen was sequenced, and it was phylogenetically related to B. aureogularis ( Fig. 2 ). Bolitoglossa aureogularis differs from B. diminuta by its larger size, SL = 48.8 mm in adult females (SL = 31.6 mm in B. diminuta ) and by contrasting the gular color of bright yellow with the belly color (venter relatively uniform in B. diminuta ).

We believe that the specimen from Tapantí (UCR24413) can be referred with high confidence to B. diminuta since it was collected near the type locality (ca. 5 km). It is an adult female of similar size and coloration pattern to the holotype ( Fig. 4 ). On the other hand, a possible scenario is that our B. diminuta specimen corresponds with B. aureogularis and we lack DNA data for B. diminuta [sensu stricto]. This last scenario is -for us- less feasible; however, due to the phylogenetic similarity between B. aureogularis and the specimen from Tapantí, it cannot be discarded.

Bolitoglossa pygmaea : This species was described by Bolaños & Wake (2009) based on 26 poorly preserved specimens from Cerro Fábregas. They described the species as miniaturized, with maximum SL = 36.8 mm in adult females; with pale coloration and black pigmented stomach and peritoneum, venter unpigmented, almost transparent; and with large nostrils. As cited above, one specimen ( UCR11218 ) of this species was collected previously in Cerro Echandi but referred to as a paratype of B. robinsoni . In March 2018, we collected an adult female (SL = 29.2 mm, Fig. 3E ) on Cerro Fábregas. This specimen was uniform bright orange. This specimen from Fábregas in ethanol changed its coloration to pale yellow, similar to the type series. In September 2015, we collected five specimens of this species on Cerro Echandi (SL = 28.5 mm in an adult male, Fig. 3F ). These were variable in coloration; most were dark brown with large blotches. We concluded that B. pygmaea is polymorphic in coloration, possibly, the Fábregas population is uniform in coloration but those from Echandi are very variable .

Figures

FIGURE 1.A) Map of the Cordillera de Talamanca in the Costa Rica-Panamá border-line region showing all known populations of the seven species within the Bolitoglossa diminuta Species Group. B) Map showing the localities for B. bramei, B. pygmaea, B. robinsoni, and B. silentium sp. nov. on the Fábregas and Echandi massifs. The open shape indicates the historical data and the solid shape indicates the localities with molecular data included herein.

FIGURE 2. Bayesian phylogenetic inference shows the relationships of the Bolitoglossa (Eladinea) subgenus based on the 16S and cyt b mitochondrial DNA gene fragments. Bootstraps proportions from maximum likelihood are shown above branches. Below the branches are shown posterior probabilities (multiplied by 100) from BEAST analysis (right) and posterior probabilities (multiplied by 100) from MrBayes analysis (left). The scale bar refers to the estimated substitutions per site. The support values of nodes within species are not shown. The asterisks represent support of 100. N.V. = no a voucher.

FIGURE 3. Photograph in preservation of (A) Bolitoglossa robinsoni (UCR11216), holotype from Cerro Echandi and inlife photographs of species found in the Talamanca Mountain range during this study. (B) B. bramei (UCR21930) from Valle del Silencio, (C) B. bramei (UCR23698) from Cerro Fábregas, (D) B. diminuta (UCR24413) from Tapantí, (E) B. pygmaea (UCR23697) from Cerro Fábregas, and (F) B. pygmaea (no collected) from Cerro Echandi. Photos by E. Arias (A,C,E), Victor Acosta (B), Brian Kubicki (D), and Omar Zúñiga (F).

FIGURE 4. Dorsal views of the body of (A) the holotype of Bolitoglossa diminuta (UCR5217) and (B) the specimen of B. diminuta from Tapantí (UCR24413) in preservation. Photographs by E.A.