Urgorri V et al. (2021), Psolidium bathygalego nom. nov. (Echinodermata,...

ECB-ART-49302

Mar Biodivers 2021 Jan 01;512:21. doi: 10.1007/s12526-020-01149-6.

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Psolidium bathygalego nom. nov. (Echinodermata, Holothuroidea) from bathyal bottoms of Galicia (NW Iberian Peninsula).

Urgorri V , Candás M , Díaz-Agras G , Cunha-Veira X , Gómez-Rodríguez C , Míguez-Rodríguez L .

Abstract
It is proposed to name the Atlantic holothuria Psolidium complanatum Cherbonnier, 1969, whose denomination is already occupied by Psolidium complanatum (Semper, 1867) from the Philippines, as Psolidium bathygalego nom. nov. 843 specimens of Psolidium bathygalego nom. nov., collected between 417 and 1191 m deep in the NW and W of Galicia and in the Galicia Bank, were studied. A detailed description of the external and internal anatomy of Psolidium bathygalego nom. nov. is made by studying the ossicles and the skeletal structure by means of scanning electron microscopy (SEM) as well as the introvert, calcareous ring, retractor muscles, water-vascular system, digestive system, respiratory trees, and reproductive system by means of micro-computed tomography (micro-CT). The habitat, feeding system, and geographical distribution of Psolidium bathygalego nom. nov. are also described.

PubMed ID: 33643475
PMC ID: PMC7901678
Article link: Mar Biodivers

Article Images: [+] show captions

	Fig. 1. Map of the distribution of Psolidium bathygalego nom. nov. to date. (yellow circle: Cherbonnier 1969, 1970; red circle: own data; blue circle: Massin 1997; Calero 2017; FernÃ¡ndez-RodrÃguez et al. 2019). (Figures made with GeoMapApp (www.geomapapp.org)/CC BY)
	Fig. 2. Psolidium bathygalego nom. nov. Habitus and details of the external appearance. a 8.5Â mm-long specimen in vivo (Stn. 20-DRR-2009-071009); b 7.1Â mm-long specimen in vivo (Stn. AT-1000-2002-090902); c 5.4Â mm-long specimen in vivo (Stn. AT-1000-2003-160903); d 8Â mm-long specimen in vivo (Stn. M16â1991-131291); e, f Dorsal and ventral view of a 7Â mm-long preserved specimen (Stn. 30â1-DRN-2008-230708); g, h Dorsal and ventral view of a 2.3Â mm-long preserved specimen (Stn. 7â1-DRN-2008-200708)
	Fig. 3. Psolidium bathygalego nom. nov. a Pattern of the tentacles of the oral area. A: mid-ventral radius; B and E: ventro-lateral radii; C and D: dorsal-lateral radii; b Oral area and oral tentacles; c Apical area of the anal cone with the five anal podia (arrows); d Oral bifid tentacles in vivo of the radius A; e Arrangement of the dorsal podia; f Anal cone with the five anal podia in vivo; g Arrangement of the ventral perimeter podia; h Specimen with 4 medial podia in the radius A; j Brown spots between the podia of the internal perimeter row; kâm Ovate clusters of small granules of the brown spots between the ventral podia; n Ovate clusters in the brown spots on the ventral sole; o Shapeless masses of small granules of the brown spots. (b, c, e Micro-CT; kâo SEM)
	Fig. 4. Psolidium bathygalego nom. nov. SEM images of the dorsal plates and the oral and anal cone plates. a Dorsal view and b ventral view, of the sequence of dorsal plates from the margin to the dorsal midline; c Large dorsal plate in ventral view; d Large dorsal plate in dorsal view; e Large middorsal plate in dorsal view; f, g Very small dorsal plates in dorsal and ventral view; h Oral cone plates; i Anal cone plates; jâm Different external ornamentation of the dorsal plates; n Pattern of the formation and growth of the dorsal plates
	Fig. 5. Psolidium bathygalego nom. nov. SEM images of ossicles of the ventral sole. aâr Different types and sizes of ossicles; s Distribution of the ossicles in the central area of the ventral sole; t Distribution of the ossicles around the base of the ventral perimeter podia
	Fig. 6. Psolidium bathygalego nom. nov. SEM images of ossicles of the ventral perimeter podia. a Different types and sizes of the apical plate of the podia of the internal perimeter row; b Different types and sizes of the apical plate of the podia of the external perimeter row; câf Different types and sizes of the ossicles of the perimeter podia; g Detail of the ventral perimeter podia; h External ventral perimeter podium; i Internal ventral perimeter podium
	Fig. 7. Psolidium bathygalego nom. nov. SEM images of ossicles of the dorsal podia. a Different types and sizes of the apical plate of the podium; bâf Different types and sizes of the ossicles of the dorsal podia; g Complete dorsal podium; h Basal section of the podium; i Middle section of the podium; j Apical section of the podium; k Anal podium
	Fig. 8. Psolidium bathygalego nom. nov. SEM images of the ossicles of the oral tentacles, introvert and calcareous ring. aâc Different types and sizes of the ossicles of the oral tentacles; dâm Different types and sizes of the ossicles around the base of the oral tentacles and introvert; nâp Interradial pieces of the calcareous ring; qât Radial pieces of the calcareous ring; u Structure of a contracted oral tentacle
	Fig. 9. Psolidium bathygalego nom. nov. a Frontal section of the overlapping of the dorsal plates at the lower level and medial plates between the oral and anal cones; b Transverse section of the overlapping of the dorsal plates at mid-body level and lateral view; c Arrangement of the oral cone plates surrounding the tentacles; d Arrangement of the anal cone plates; e Longitudinal section of the anterior part of the digestive tract; f Calcareous ring in inferior and lateral view; g Longitudinal section of the posterior part of the digestive tract; h Transverse section of the stomach and intestine; j Transverse section of the esophagus; k Longitudinal section of the stomach; m Longitudinal section of the intestine; n Large Foraminifera under the anal cone; o Gastric repletion in the intestine; p Schematic drawing of the regionalization of the digestive system. (aâo Micro-CT; except câd SEM)
	Fig. 10. Psolidium bathygalego nom. nov. Micro-CT images of water-vascular system and retractor muscles. a Longitudinal section of the anterior part showing the ring canal, Polian vesicle, and stone canal; b Posterior view of the ring canal and arrangement of the 5 radial longitudinal retractor muscles; c Schematic drawing of the water-vascular system; d Posterior confluence of the radial canals of the trivium: A-B-E; e Arrangement and anterior confluence of the radial canals of the trivium: A-B-E and radial longitudinal retractor muscles: A-B-E; f Schematic drawing of the radial longitudinal retractor muscles; g Arrangement after the calcareous ring of the five radial canals and longitudinal retractor muscles; h Union of the radial B canal arising from the ring canal with radial canal B running backwards attached to the body wall and insertion in the calcareous ring of the radial longitudinal retractor muscles B and C; i Tentacle, tentacular ampullae, retractor muscle A, and radial canal A; j Radial canals A and B and radial retractor muscles A and B; k Posterior end of the longitudinal retractor muscle C in radial canal C
	Fig. 11. Psolidium bathygalego nom. nov. aâd Different arrangement and repletion of the digestive tract (a-c dorsal, d ventral); e Male gonad; f Female gonad; g Ventral view of a male specimen; h Ventral view of a female specimen; i Mature female gonad; j Two male gonadal tubules; k Poorly developed female gonadal tubule; l Gonadal tubule with developed oocytes; m Different sizes of oocytes; n, o Drawings of respiratory trees in dorsal and ventral view; p, q Reconstruction of respiratory trees; r End of a branch of the respiratory tree and detail of the small rounded vesicles; s Contracted retractor muscles; t Irregular reticulation of the possible canals of the dorsal podia (arrows). (aâf, p, q 3D reconstruction with AVIZO 6.4; i micro-CT)
	Fig. 12. Psolidium bathygalego nom. nov. a SEM images of ossicles of the gonadal tubules of males and females; b, c Ossicles in the gonadal tubules of females (b) and males (c); d SEM images of ossicles of the respiratory trees; e Ossicles in situ in respiratory trees; f Arrangement in situ of the ossicles in the basal branches of the respiratory trees. (a, d SEM; f micro-CT)

References [+] :

Faulwetter, Micro-computed tomography: Introducing new dimensions to taxonomy. 2013, Pubmed