|Pedioplanis branchi & Pedioplanis mayeri |
Childers, Kirchhof & Bauer, 2021
The lacertid genus Pedioplanis is a moderately speciose group of small-bodied, cryptically-colored lizards found in arid habitats throughout southern Africa. Previous phylogenetic work on Pedioplanis has determined its placement within the broader context of the Lacertidae, but interspecific relations within the genus remain unsettled, particularly within the P. undata species complex, a group largely endemic to Namibia. We greatly expanded taxon sampling for members of the P. undata complex and other Pedioplanis, and generated molecular sequence data from 1,937 bp of mtDNA (ND2 and cyt b) and 2,015 bp of nDNA (KIF24, PRLR, RAG-1) which were combined with sequences from GenBank resulting in a final dataset of 455 individuals. Both maximum likelihood and Bayesian analyses recover similar phylogenetic results and reveal the polyphyly of P. undata and P. inornata as presently construed. We confirm that P. husabensis is sister to the group comprising the P. undata complex plus the Angolan sister species P. huntleyi + P. haackei and demonstrate that P. benguelensis lies outside of this clade in its entirety. The complex itself comprises six species including P. undata, P. inornata, P. rubens, P. gaerdesi and two previously undescribed entities. Based on divergence date estimates, the P. undata species complex began diversifying in the late Miocene (5.3 ± 1.6 MYA) with the most recent cladogenetic events dating to the Pliocene (2.6 ± 1.0 MYA), making this assemblage relatively young compared to the genus Pedioplanis as a whole, the origin of which dates back to the mid-Miocene (13.5 ± 1.8 MYA). Using an integrative approach, we here describe Pedioplanis branchi sp. nov. and Pedioplanis mayeri sp. nov. representing northern populations previously assigned to P. inornata and P. undata, respectively. These entities were first flagged as possible new species by Berger-Dell’mour and Mayer over thirty years ago but were never formally described. The new species are supported chiefly by differences in coloration and by unique amino acid substitutions. We provide comprehensive maps depicting historical records based on museum specimens plus new records from this study for all members of the P. undata complex and P. husabensis. We suggest that climatic oscillations of the Upper Miocene and Pliocene-Pleistocene era in concert with the formation of biogeographic barriers have led to population isolation, gene flow restrictions and ultimately cladogenesis in the P. undata complex.
Key Words: Biogeography, molecular phylogeny, phylogenetics, southern Africa, species description, taxonomy
Pedioplanis inornata “South”/P. inornata “Central”
The type series of Eremias inornata Roux, 1907 comprises eight specimens collected from “Oranje-Fluß, Kl.-Namaqualand” [the Orange River, Little Namaqualand, Northern Cape, Province, South Africa]. Syntype ZMA11049 (Zoological Museum Amsterdam) was subsequently designated as the lectotype (Daan and Hillenius 1966). The ZMA collections have subsequently been incorporated into those of the Naturalis Biodiversity Center in Leiden (RMNH). The geographic origin of the specimens and the relatively detailed description and accompanying plate, clearly tie the name-bearing lectotype of Pedioplanis inornata to the P. inornata “South” clade. No other nomina are currently within the synonymy of Pedioplanis inornata and none are available for application to the P. inornata “Central” clade, which is here described as:
Pedioplanis branchi sp. nov.
Etymology: The specific epithet is a patronym formed in the genitive singular honoring our friend and colleague, the British-born South African herpetologist, William Roy Branch (1946–2018), in recognition of his many contributions to African herpetology and in remembrance of many happy trips in the field together.
Distribution: Pedioplanis branchi sp. nov. is endemic to the Erongo Region in Namibia. Its range stretches from just south of the Swakop River in the South, where it occurs in parapatry with P. husabensis, through the pro-Namib, to the Ugab River and the Brandberg in the north and Mount Erongo and Otjimbingwe in the east, probably occurring in parapatry with P. mayeri all along its northeastern border (see Fig. 6 for map of locality records).
Pedioplanis undata “South”/P. undata “North”
Mayer and Böhme (2000) examined the type material of Lacerta undata Smith, 1838 and noted that the rediscovered syntype specimens in the National Museums of Scotland collection were, in fact, representatives of the taxon long associated with the name Pedioplanis lineoocellata pulchella (Gray, 1845) and now, based on the findings of Edwards (2013), considered as P. lineoocellata (Duméril & Bibron, 1839). They proposed to conserve the current usage of names within Pedioplanis by calling on the ICZN in Case 3085 to set aside the original type designation and recognize the designation of a neotype for L. undata. Opinion 1992 of the ICZN (Anonymous 2002) accepted this solution and thus the neotype was fixed as Naturhistorisches Museum Wien (NMW) 31886 from “near Windhoek, Namibia.” This links the name P. undata to the P. undata “South” clade. The assignment of the name Pedioplanis undata to the more restricted, southern clade is notable in that the predominant concept of the species based on previous studies of P. undata is largely affiliated with populations and representative specimens from the more broadly distributed northern clade (Branch 1998; Makokha et al. 2007; Conradie et al. 2012). In these cases the presence of bold dorsal stripes was considered diagnostic for the species, however based on our results this character is now largely applicable to the unnamed northern clade, and is exhibited inconsistently and with variation among true P. undata. No other nomina are currently within the synonymy of Pedioplanis undata and none are available for application to the P. undata “North” clade, which we describe as:
Pedioplanis mayeri sp. nov.
Etymology: The specific epithet is a patronym formed in the genitive singular honoring our friend and colleague, the Austrian lacertid specialist Werner Mayer (1943–2015), who first recognized the distinctiveness of his namesake species and whose contributions to the study of Pedioplanis have been seminal.
Distribution: Pedioplanis mayeri sp. nov. is endemic to northern Namibia and occurs from south of the Kunene River and east of the Namib Desert along the eastern side of the escarpment, thence throughout the eastern Kunene Region, entering the northeastern parts of the Erongo Region and east through the Otjozondjupa Region, reaching at least as far east as Oshikango (TM17028) in the north, Gobabis (Omaheke Region) in the south-east, and Nauchas in the south. It does not enter the Kalahari dune fields, and is possibly absent from the Khomas Hochland, where it is replaced by P. undata (see Fig. 6 for map of locality records).
Jackie L. Childers, Sebastian Kirchhof and Aaron M. Bauer. 2021. Lizards of A Different Stripe: Phylogenetics of the Pedioplanis undata Species Complex (Squamata, Lacertidae), with the Description of Two New Species. Zoosystematics and Evolution. 97(1): 249-272. DOI: 10.3897/zse.97.61351