Sunday, September 30, 2018

[Crustacea • 2018] Pagurus fraserorum MicroCT Imaging Applied to Description of A New Species of Pagurus Fabricius, 1775 (Decapoda: Anomura: Paguridae) from South Africa, with Selection of Three-dimensional Type Data


 Pagurus fraserorum  Landschoff & Komai

in Landschoff, Komai, du Plessis, Gouws & Griffiths, 2018.

Abstract
A new species of hermit crab, Pagurus fraserorum n. sp. (family Paguridae) is described from rocky subtidal reefs off KwaZulu-Natal, South Africa, and illustrated using both conventional drawings and colour photographs, and via three-dimensional (3D) X-ray micro-computed tomography (μCT). Because of the limitation μCT has in detecting very fine and soft structures, a novel approach of manually drawing setation and spinulation onto the two-dimensional images of the 3D visualizations was used to illustrate the pereopods. In addition, an interactive figure and rotation movie clips in the supplement section complement the species description, and the 3D raw data of the 3D type data are downloadable from the Gigascience Database repository. The new species is the sixth species of Pagurus Fabricius, 1775 reported from South Africa and is closely allied to the Indo-Pacific P. boriaustraliensis Morgen, 1990 and P. pitagsaleei McLaughlin, 2002, from which it differs by its shorter ocular peduncles, by the armature of the carpus of the right cheliped, and also in colouration. This study presents the first description of a hermit crab in which a majority of taxonomic details are illustrated through 3D volume-rendered illustrations. In addition, colour photographs and COI molecular barcodes are provided, and the latter compared to COI sequences of specimens from Western Australia previously identified as P. boriaustraliensis and of specimens of P. pitagsaleei from Taiwan, as well as to three additional South African members of the genus. The South African taxon was confirmed to be genetically distinct from all species tested.

 Taxonomy
Family Paguridae Latreille, 1802

Genus Pagurus Fabricius, 1775

Pagurus fraserorum Landschoff & Komai, n. sp.

Fig 6. Pagurus fraserorum n. sp., colouration in life or fresh.
(A) male holotype 2.7 mm (SAMC MB-A066790), dorsal view; (B) ovigerous female paratype 2.4 mm (SAMC MB-A066770), dorsal view; (C) holotype, frontal view, in shell; (D) female paratype 2.4 mm (SAMC MB-A066407), left lateral view, parasitized by undescribed parasitic gills isopod Pseudionella sp..


Pagurus fraserorum n. sp., colouration in life or fresh.  male holotype 2.7 mm (SAMC MB-A066790), frontal view, in shell.


Pagurus fraserorum n. sp., colouration in life or fresh.  (D) female paratype 2.4 mm (SAMC MB-A066407), left lateral view, parasitized by undescribed parasitic gills isopod Pseudionella sp..

Distribution: Known from rocky reefs off Pumula and Hibberdene, near Port Shepstone, KwaZulu-Natal, South Africa, and from a photographic record from Vetch’s Pier, Durban, South Africa; 6–20 m depth.

Parasites: Host of an undescribed parasitic bopyrid isopod Pseudionella sp. (Fig 6D) that is currently being described by Williams & Landschoff, and of a second parasitic isopod, Pseudione sp., both inhabiting the branchial chamber.

Etymology: The species is named after the Fraser family, in particular Valda and Mike, but also to their son Allan and honours their deep passion for the marine world and the many exciting species discoveries they have made in South African waters. Mike and Valda generously hosted the senior author and his supervisor Charles L. Griffiths over the collection trip in October 2015, when this species was first recorded. This sampling would have not been possible without the use of the facilities and guidance they provided.


Jannes Landschoff, Tomoyuki Komai, Anton du Plessis, Gavin Gouws and Charles L. Griffiths. 2018. MicroCT Imaging Applied to Description of A New Species of Pagurus Fabricius, 1775 (Crustacea: Decapoda: Anomura: Paguridae), with Selection of Three-dimensional Type Data. PLoS ONE. 13(9): e0203107. DOI: 10.1371/journal.pone.0203107


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