MicroCT imaging applied to description of a new species of Pagurus Fabricius, 1775 (Crustacea: Decapoda: Anomura: Paguridae), with selection of three-dimensional type data

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.

Extended depth of focus ultraviolet imaging compared with laser scanning confocal microscopy for the study of micro‐Arthropoda surface texture, with the description of a new species of Brachypodopsis (Acari: Hydrachnidia)

“…With the advent of digital photography and the development of new microscopic techniques, the rendering of diagnostic features in a realistic context is closely approaching. Nevertheless, even with highly sophisticated techniques such as micro‐CT scans, drawings that complement images (either separate to or superimposed on images) are sometimes still needed for a complete and highly informative rendering of a structure (Landschoff et al, 2018).…”

“…Besides drawings, an extensive array of imaging techniques can be used, from cameras attached to bright field microscopes to more sophisticated laser scanning confocal microscopes (LSCM) (Valdecasas, 2008) or electron microscopes, either classical or environmental (Valdecasas & Camacho, 2005). In addition, the use of CT‐scanning techniques, which allow for the 3D rendering of structures, has become almost routine for new species descriptions (Landschoff, Komai, du Plessis, Gouws, & Griffiths, 2018, and references therein). Using images can be a complex process as it involves many procedures, beginning from specimen preparation to image acquisition and image processing, with some methodologies better suited for some organisms than for others.…”

An earliest Triassic age forTasmaniolimulusand comments on synchrotron tomography of Gondwanan horseshoe crabs

“…The increasing availability of three-dimensional (3D) imaging techniques in the preceding two decades has revolutionised the acquisition of morphological data from both biological ( Hita Garcia et al, 2017 ; Parapar et al, 2017 ; Landschoff et al, 2018 ; Marcondes Machado, Passos & Giribet, 2019 ; Raymond et al, 2019 ) and palaeontological specimens ( Sutton, 2008 ; Pardo & Anderson, 2016 ; Liu, Rühr & Wesener, 2017 ; Liu et al, 2019 ; Forel, Poulet-Crovisier & Korat, 2021 ). Traditional lab-based micro-computed tomography (CT), along with more sophisticated synchrotron radiation X-ray tomography (SRXT) and neutron micro-tomography (NCT) have permitted non-destructive visualisation of previously unknown and inaccessible morphological features for taxa across all of Metazoa ( Donoghue et al, 2006 ; Tafforeau et al, 2006 ; Sutton, 2008 ; Metscher, 2009 ; Motchurova-Dekova & Harper, 2010 ; Faulwetter et al, 2013 ; Faulwetter et al, 2014 ; Herrera et al, 2020 ; Snyder et al, 2020 ).…”

Peer Review #2 of "An earliest Triassic age for Tasmaniolimulus and comments on synchrotron tomography of Gondwanan horseshoe crabs (v0.1)"

“…The increasing availability of three-dimensional (3D) imaging techniques in the preceding two decades has revolutionised the acquisition of morphological data from both biological (Hita Garcia et al, 2017;Parapar et al, 2017;Landschoff et al, 2018;Marcondes Machado et al, 2019;Raymond et al, 2019) and palaeontological specimens (Sutton, 2008;Pardo & Anderson, 2016;Liu et al, 2017Liu et al, , 2019Forel et al, 2021). Traditional lab-based micro-computed tomography (CT), along with more sophisticated synchrotron radiation X-ray tomography (SRXT) and neutron micro-tomography (NCT) have permitted non-destructive visualisation of previously unknown and inaccessible morphological features for taxa across all of Metazoa (Donoghue et al, 2006;Tafforeau et al, 2006;Sutton, 2008;Metscher, 2009;Motchurova-Dekova & Harper, 2010;Faulwetter et al, 2013Faulwetter et al, , 2014Herrera et al, 2020;Snyder et al, 2020).…”