Sunday, November 13, 2022

[Herpetology • 2022] Leptopelis shebellensis & L. xeniaeGenetic and Morphometric Analyses of Historical Type Specimens Clarify the Taxonomy of the Ethiopian Leptopelis gramineus Species Complex (Anura, Arthroleptidae)


Leptopelis shebellensis & Leptopelis xeniae
Goutte, Reyes-Velasco, Kassie & Boissinot, 2022


Abstract
Frogs of the genus Leptopelis have diversified in the Ethiopian Highlands to occupy forests and montane grasslands both east and west of the Great Rift Valley. Genetic studies revealed that the endemic species Leptopelis gramineus (Boulenger, 1898) comprises multiple unnamed taxa. A careful examination of historical type specimens is, however, needed to fully resolve the taxonomy of the group. Here we use mitochondrial DNA and morphological analyses on a large sample of recently-collected Ethiopian Leptopelis, as well as century-old type specimens to demonstrate that the recently resurrected L. montanus Tiutenko & Zinenko, 2021 (previously Pseudocassina ocellata Ahl, 1924) is a junior synonym of L. rugosus (Ahl, 1924) and corresponds to the taxon found west of the Great Rift Valley, not east as previously thought. Our results show that populations inhabiting the mountains and plateaus east of the Rift constitute a distinct and undescribed species. We provide a re-description of L. rugosus and describe two new species inhabiting the Highlands east of the Great Rift Valley. We provide an identification key, as well as a description of the calls of the members of the Leptopelis gramineus species complex.

Keywords: African treefrogs, Afromontane, historical DNA, integrative taxonomy, Leptopelis shebellensis sp. nov., Leptopelis xeniae sp. nov., museomics, new species

 Leptopelis rugosus (Ahl, 1924)
Diagnosis: A large (male (n = 22) SVL 38.7 ± 2.7 mm, female (n = 2) SVL 52.4 ± 0.2 mm) species of the Leptopelis gramineus species complex (Figs 5, 6). Robust, semi-fossorial form. It differs from other members of the Leptopelis gramineus species complex by the following combination of characters: (1) large tympanum (male TD/ED 0.57 ± 0.11, female TD/ED 0.54), (2) long snout (male SL/HL 0.25 ± 0.02, female SL/HL 0.27 ± 0.01), (3) well-developed metatarsal tubercle (male MTL/FL 0.17 ± 0.02, female MTL/FL 0.18 ± 0.02), (4) ventrum lacking any brown spots, (5) yellow colouration on the side of the ventrum and the inner thighs almost always present.


 Leptopelis shebellensis Goutte, Reyes-Velasco, Kassie & Boissinot, sp. nov.
 Common name: Shebelle River burrowing African treefrog.

Diagnosis: Medium to large (male (n = 21) SVL 35.9 ± 3.5 mm, female (n = 5) SVL 53.4 ± 5.3 mm), robust semi-fossorial species of the Leptopelis gramineus species complex (Fig. 7). It differs from other members of the Leptopelis gramineus species complex by the following combination of characters: (1) short and robust hind-limbs (male TL/SVL 0.33 ± 0.03, female TL/SVL 0.30 ± 0.02), (2) well-developed metatarsal tubercle (male MTL/FL 0.17 ± 0.03, female MTL/FL 0.16 ± 0.02), (3) longer snout (male SL/HL 0.23 ± 0.03, female SL/HL 0.24 ± 0.02), (4) toe and fingertips not enlarged and (5) ventrum often with dark brown spots and/or yellowish sides.

Etymology: The specific name refers to the Shebelle River, as the distribution range of the species appears restricted to the Shebelle River Basin, with populations found both north and south of the source of the river (Fig. 1).




 Leptopelis xeniae Goutte, Reyes-Velasco, Kassie & Boissinot, sp. nov.
 Common name: English: Xenia’s African treefrog.
 
Diagnosis: Small to medium-sized (male (n = 20) SVL 27.6 ± 2.0 mm, female (n = 2) SVL 43.5 ± 5.7 mm), robust arboreal species of the Leptopelis gramineus species complex (Fig. 8). It differs from other members of the Leptopelis gramineus species complex by the following combination of characters: (1) thin, elongated hind-limbs (male TL/SVL 0.36 ± 0.02, female TL/SVL 0.37 ± 0.03), (2) small metatarsal tubercle (male MTL/SVL 0.07 ± 0.01, female MTL/SVL 0.06 ± 0.00) (2) inter-orbital distance very short (male IOD/ED 0.88 ± 0.16, female IOD/ED 0.69 ± 0.12), (3) dorsal skin always smooth, except in females where it may be slightly rugose, (4) absence of yellow colouration on the ventrum or inner thighs.

Etymology: Leptopelis xeniae sp. nov. is named after Xenia Freilich, who conducted her doctoral research on Ethiopian anurans, including the Leptopelis gramineus complex.


 Sandra Goutte, Jacobo Reyes-Velasco, Abeje Kassie and Stéphane Boissinot. 2022. Genetic and Morphometric Analyses of Historical Type Specimens Clarify the Taxonomy of the Ethiopian Leptopelis gramineus Species Complex (Anura, Arthroleptidae). ZooKeys. 1128: 63-97.  DOI: 10.3897/zookeys.1128.82176