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| Brachiomya ducentiunus Valentich-Scott, Griffiths, Landschoff, R. Li & J. Li, 2024. |
Abstract
The Galeommatoidea are a diverse but little-studied group of small bivalves, well known for the symbiotic relationships many species have with a range of invertebrate taxa. Four species collected from the Western Cape region of South Africa were examined and illustrated, providing new details on their habitat preferences, and depicting the mantle structure of live specimens for the first time. Brachiomya ducentiunus sp. nov., is described herein, and an additional record of Montacuta substriata (Montagu, 1808) is reported from South Africa. Brachiomya ducentiunus and Montacuta substriata have obligate symbiotic relationships with different burrowing echinoids, while Kellia becki (WH Turton, 1932) and Melliteryx mactroides (Hanley, 1857) are free-living. DNA data and phylogenetic analyses are provided for three of the species.
Key words: Biodiversity, commensalism, heart urchin, South Atlantic Ocean, Spatagobrissus mirabilis, Spatangus capensis, symbiosis, taxonomy
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| Brachiomya ducentiunus new species, living animals A, B crawling on hard substrate C overview of specimens crawling on the aboral surface of urchin Spatagobrissus mirabilis D crawling on urchin spine with mantle and foot extended E, F extended mantle between urchin spines. |
Brachiomya ducentiunus sp. nov.
Discovery: Initially discovered via free-diving in 2016 at the type locality, collected by Jannes Landschoff and Craig Foster.
Etymology: The name ducentiunus is from Latin, meaning “201.” The species was discovered while preparing and working on the ‘1001 Seaforest Species’ project, a research and storytelling program aimed at increasing awareness of regional kelp bed ecosystems colloquially referred to as ‘the Great African Seaforest’ (see www.seachangeproject.com). The number 201 was chosen as a unique identifier for the 1001 program, with the goal to link each hundredths species to a species described as new to science.
Comparisons: The Pacific and Asian Brachiomya stigmatica, which is the only other known species in the genus, is more evenly rounded anteriorly, has a strong rust-colored stripe medially, lacks radial striae, and has more developed teeth.
Paul Valentich-Scott, Charles Griffiths, Jannes Landschoff, Ruiqi Li, Jingchun Li. 2024.
Bivalves of Superfamily Galeommatoidea (Mollusca, Bivalvia) from western South Africa, with Observations on Commensal Relationships and Habitats. ZooKeys. 1207: 301-323. DOI: doi.org/10.3897/zookeys.1207.124517
