Cryptic speciation in the giant Antarctic isopod Glyptonotus antarcticus (Isopoda, Valvifera, Chaetiliidae)

• Published in: Scientia Marina
• Main Authors: Christoph Held, Johann Wolfgang Wägele
• Format: Article in Journal/Newspaper
• Language: English
• Published: Consejo Superior de Investigaciones Científicas 2005
• Subjects: sibling species; molecular systematics; biogeography; antarctic benthos; Aquaculture. Fisheries. Angling; SH1-691; Antarctic; Antarctic Peninsula; Ross Sea; The Antarctic; Weddell; Weddell Sea; Antarc*; antarcticus
• Online Access: https://doi.org/10.3989/scimar.2005.69s2175; https://doaj.org/article/b942acdda8c44baf964182327ae1851d

The genus Glyptonotus is most commonly regarded as monospecific, with Glyptonotus antarcticus Eights 1852 being its only constituent. Two more forms (G. acutus, G. antarcticus var. obtusus) that had been described based on morphological evidence have received little attention in the literature, though no formal attempt to evaluate their taxonomic status has been undertaken. In a survey of within-species genetic diversity, 23 specimens of the benthic Antarctic isopod Glyptonotus antarcticus from three sampling areas around the Antarctic had a high genetic variability in their mitochondrial LSU (16S) gene. Eleven unique mitochondrial haplotypes were found, two at the Antarctic Peninsula (AP), two in the Ross Sea (RS) and seven in the Eastern Weddell Sea (EWS). Average haplotype variation within sampling areas (AP, RS, EWS) was one order of magnitude less than between sampling areas. In the EWS, however, two highly differentiated haplotypes co-exist. These four groups of haplotypes may represent cryptic, but reproductively isolated species rather than a single species.