Thursday, March 4, 2021

[Herpetology • 2021] Paroedura renneraeCompleting A Taxonomic Puzzle: Integrative Review of Geckos of the Paroedura bastardi Species Complex (Squamata, Gekkonidae)

Paroedura rennerae 
Miralles, Bruy, Crottini, Rakotoarison, Ratsoavina, Scherz, Schmidt, Köhler, Glaw & Vences, 2021

The Paroedura bastardi clade, a subgroup of the Madagascan gecko genus Paroedura, currently comprises four nominal species: P. bastardi, supposedly widely distributed in southern and western Madagascar, P. ibityensis, a montane endemic, and P. tanjaka and P. neglecta, both restricted to the central west region of the island. Previous work has shown that Paroedura bastardi is a species complex with several strongly divergent mitochondrial lineages. Based on one mitochondrial and two nuclear markers, plus detailed morphological data, we undertake an integrative revision of this species complex. Using a representative sampling for seven nuclear and five mitochondrial genes we furthermore propose a phylogenetic hypothesis of relationships among the species in this clade. Our analyses reveal at least three distinct and independent evolutionary lineages currently referred to P. bastardi. Conclusive evidence for the species status of these lineages comes from multiple cases of syntopic occurrence without genetic admixture or morphological intermediates, suggesting reproductive isolation. We discuss the relevance of this line of evidence and the conditions under which concordant differentiation in unlinked loci under sympatry provides a powerful approach to species delimitation, and taxonomically implement our findings by (1) designating a lectotype for Paroedura bastardi, now restricted to the extreme South-East of Madagascar, (2) resurrecting of the binomen Paroedura guibeae Dixon & Kroll, 1974, which is applied to the species predominantly distributed in the South-West, and (3) describing a third species, Paroedura rennerae sp. nov., which has the northernmost distribution within the species complex.

Keywords: Madagascar, new species, phylogenetics, species delimitation, sympatry, taxonomy.

Figure 4. Multilocus phylogenetic trees (full dataset concatenated, nDNA and mtDNA concatenated trees), with haplotype networks reconstructed for each of the nuclear markers (after phasing). Photo credits: AM (Paroedura rennerae sp. nov., P. picta, both from Kirindy), MV (P. ibityensis from Itremo), FG and JK (P. neglecta and P. tanjaka, both from Bemaraha), FG and MV (P. bastardi from Berenty, and P. guibeae from Tranoroa).

Figure 9. Holotype of Paroedura rennerae sp. nov. (ZSM 849/2010, from Kirindy CNFEREF).
The four top photographs are of the living specimen, whereas the bottom picture shows the preserved specimen after nine years in 70% ethanol (pictures by Aurélien Miralles).

Paroedura rennerae sp. nov.
Remarks: This species was previously named P. sp. aff. bastardi Ca01 “Marofandilia/Miandrivazo” by Cocca et al. (2018) and Paroedura bastardi by Aprea et al. (2013) and Köhler et al. (2019; partim).
Paroedura rennerae sp. nov. is characterized by the unique combination of the following characters: (1) presence of prominent dorsal tubercles arranged in regular longitudinal rows, (2) presence of three broad light crossbands on the dorsum in juveniles and subadults, (3) spines on the tail, (4) nostril separated from rostral scale by prenasal, and (5) a curly-bracket shaped marking in the occipital region.

Paroedura rennerae sp. nov. can be distinguished from most other currently recognized Paroedura species by the presence of only three broad light crossbands on the dorsum in juveniles and subadults (the first one between forelimbs, the second one at midbody, and the third one between hindlimbs) versus four light crossbands in all other species except those of the P. bastardi clade (P. bastardi, P. guibeae, P. ibityensis, P. neglecta, and P. tanjaka, which all have three crossbands) and P. oviceps and P. vahiny (in which the juvenile coloration is still unknown). It can be distinguished from P. gracilis by larger dorsal scales, absence of a white tip to the original tail, absence of a raised vertebral ridge on the dorsum and shorter forelimbs, which do not extend forward beyond tip of snout; from P. masobe by much smaller eyes and absence of a dorsal row of paired spines on the tail; from P. fasciata, P. homalorhina, P. hordiesi, P. vahiny, and P. spelaea by presence of spines on the original tail (versus absence); from P. gracilis, P. homalorhina, P. kloki, P. maingoka, P. masobe, P. oviceps (from its type locality Nosy Be), P. picta, P. spelaea, most P. tanjaka, and P. vahiny by the presence of prominent dorsal tubercles arranged in regular longitudinal rows (versus rather irregular rows of dorsal tubercles).

Within the P. bastardi clade, the species can easily be distinguished from P. tanjaka and P. neglecta by the absence of contact between the nostril and the rostral scale (versus presence). It can be distinguished from P. ibityensis by larger maximum SVL (> 70 mm versus 61 mm). In comparison with P. bastardi sensu novo and P. guibeae, the new species can be distinguished by the presence of a very sharp and contrasting dark transverse pattern, evoking the shape of a thin curly-bracket ({) , in the occipital region and delimiting the skull from the neck. Moreover, Paroedura rennerae sp. nov. is unambiguously larger in size than P. guibeae (adult SVL > 70 mm versus < 60 mm in P. guibeae), and its dorsal tubercles are more prominent. It also lacks striped fingers (versus striped in P. guibeae), and the light patch on its head lacks concave anterior edge and central vacuity in juveniles (versus both present in P. bastardi).

Etymology: This new species, elegant and prickly, is dedicated to Susanne Renner, eminent botanist and evolutionary biologist, and Professor Emeritus of the University of Munich, in recognition of her substantial contributions to taxonomy and her invaluable collaboration in the framework of the “Taxon-omics” priority program of the German Research Foundation, DFG.

Habitat, habits, and distribution: Paroedura rennerae is reliably known from five localities, some of them relatively distant from each other, suggesting this species is widely distributed in the central/southern region of Madagascar. In the dry forest of Kirindy CNFEREF, specimens have been observed on vertical surfaces (tree trunks, wooden walls of the CNFEREF camp huts), around 1 to 2 m above the ground. Like other members of the P. bastardi species complex, it is quick to bite when handled. In Anja, several specimens have been collected on granitic boulders. ZSM 779/2009 was found in a large cavity below two large granitic boulders, in a quite humid environment. In this cavity, ZSM 779/2009 and other individuals were found on the walls. In Isalo, specimens belonging to this species were found at two sites (Zahavola and Namazaha Valley). These individuals were found within the canyons of the sandstone Massif in shaded areas and in close proximity to a small cave or a small waterfall, again in quite humid microhabitats. Two additional 16S sequences confirm the presence of this species also in Marofandilia and Miandrivazo (GU129005 and GU128989, Aprea et al. 2013). All specimens have been observed at night or near dusk.

Aurélien Miralles, Teddy Bruy, Angelica Crottini, Andolalao Rakotoarison, Fanomezana M. Ratsoavina, Mark D. Scherz, Robin Schmidt, Jörn Köhler, Frank Glaw and Miguel Vences. 2021. Completing A Taxonomic Puzzle: Integrative Review of Geckos of the Paroedura bastardi Species Complex (Squamata, Gekkonidae). Vertebrate Zoology. 71: 27-48. DOI: 10.3897/vertebrate-zoology.71.e59495