Integrative taxonomy provides evidence for a cryptic lineage in the velvet worm Peripatopsis birgeri species complex (Onychophora: Peripatopsidae) in KwaZulu-Natal, South Africa

Abstract

During the present study, species boundaries in the velvet worm Peripatopsis birgeri species complex in KwaZulu-Natal, South Africa, were examined with the use of DNA sequence data, gross morphology, scanning electron microscopy (SEM) and ecological niche modelling. Mitochondrial CO1 and nuclear 18S rRNA sequence data were used to generate a phylogeny using both a Bayesian inference and maximum likelihood approaches. Both the CO1 sequence data and the combined DNA sequence topology (CO1 + 18S rRNA) revealed the presence of two geographically distinct clades within the P. birgeri species complex. Results from three species delimitation methods (GMYC, PTP and ASAP), were incongruent in determining the number of species within the species complex and generally overestimated the number of operational taxonomic units. The latter result can be attributed to the marked genetic structure within the species complex, a result corroborated by the CO1 haplotype network and statistically significant F_ST values. Divergence time estimation suggests that the two clades diverged during the Plio/Pleistocene. Niche modelling revealed that the two clades were differentially impacted by bioclimatic variables and occupied different habitats. Gross morphological characteristics, such as leg pair numbers and colour revealed no fixed differences between the two clades, however, a creamy white headband/collar occurred exclusively in specimens of clade 1 (P. birgeri). In contrast, SEM revealed fixed dorsal and ventral scale rank differences between the two clades. The results corroborate the presence of a novel species within the P. birgeri s.s. species complex. Peripatopsis birgeri s.s. is revised and restricted to the southern Drakensberg and a new species, P. polychroma sp. nov. (clade 2), from the northern Drakensberg and adjacent Afrotemperate forests in the interior of KwaZulu-Natal is described.

https://zoobank.org/urn:lsid:zoobank:org:pub:569557AB-8BC8-49B6-B8AA-96507371297B

Key Words:

• Allopatry
• cladogenesis
• climatic oscillations
• conserved morphology
• Velvet worm

Acknowledgements

The Central Analytic Facility DNA sequencing unit at Stellenbosch University is thanked for DNA sequencing, while Madelaine Frazenburg is thanked for her help with the SEM. Theo Busschau is thanked for collecting the Coleford Nature Reserve and Qudene Forest specimens. Jed Luke Davidson is thanked for his help with the fieldwork to the Drakensberg Mountains. Miguel da Fonseca is thanked for sharing collection records of P. birgeri s.s. We are grateful to Matabaro Ziganira and Aisha Mayekiso of the KwaZulu-Natal Museum and Iziko Museums of Cape Town respectively for a specimen loan and the latter for providing museum accession numbers. Ezemvelo KZN Wildlife is thanked for a collection permit. Private land owners are thanked for allowing us to sample on their properties. Dr Amanda Reid is thanked for discussing the colour variation in Australian velvet worms. An anonymous reviewer and the associate editor are thanked for constructive criticism that improved the overall quality of the manuscript.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Supplemental material

Supplemental material for this article can be accessed here: https://doi.org/10.1080/14772000.2023.2207574.

Associate Editor: Dr Christoph Bleidorn