Thyone florianoi, Martins & Tavares, 2018

Martins, Luciana & Tavares, Marcos, 2018, New species of the genera Havelockia and Thyone (Echinodermata: Holothuroidea) and first record of T. crassidisca from the southwestern Atlantic Ocean, Zootaxa 4407 (4), pp. 533-542 : 535-538

Thyone florianoi sp. nov.

( Figs 3–4 )

Type material. Holotype: Brazil: São Sebastião, São Paulo, 1.ii.1986, depth unknown, 1 spm, 15 mm ( MZUSP 1351). Paratypes: Same locality and date as holotype, 2 spms, 100 mm ( MZUSP 1529); Ilha Anchieta, Ubatuba, São Paulo, 15.ii. 1964, 11 m, 2 spms 20–25 mm long ( MZUSP 1516).

Type locality. São Sebastião , São Paulo, Brazil.

Etymology. This species is named in honour of Mr. Floriano de Oliveira Junior, Vice-Consul of the Embassy of Brazil in Washington, D.C., in recognition for the valuable support lent to LM.

Diagnosis. Body wall tables two-pillared with four-holed discs. Introvert with tables and rosettes. Tube feet with supporting tables and plates.

Description. Body U-shaped, slightly upturned at both ends ( Fig. 3A ). Color brown in ethanol. Tube feet in double rows in the ambulacra and scattered in the interambulacra.

Ten tentacles, ventral pair reduced. Anus surrounded by five papillae. One Polian vesicle (fig. 3E). Longitudinal muscle flat, undivided; retractor muscles attached to radial plates, tapering distally ( Fig. 3C ). Madreporite globular ( Fig. 3D ). Calcareous ring tubular, mosaic-like; radial plates notched anteriorly with long, divided forked processes; interradial plate pointed anteriorly.

Radial and interradial plates equal in length, united along its entire length ( Fig. 3B ). Body wall and anal ossicles: two-pillared tables, disc oval, four-holed, margins undulating; spire tapering (80–90 µm long; Fig. 4A, B ). Tentacles ossicles: rosettes (10–30 µm long; Fig. 4C ). Introvert ossicles: two-pillared tables, disc oval, completely perforated; spire ending in three, four teeth and rosettes (60-70 µm long; Fig. 4 D–F ). Tube feet ossicles: supporting tables two-pillared, disc curved, 4 central holes, single perforated ends; spire tapering (90–130 µm long; Fig. 4G ). Flat perforated plates (80–90 µm long; Fig. H) and end plate with large holes around margin, smaller ones medially (200–220 µm long; Fig. 4I ).

Remarks. Thyone florianoi sp. nov. falls into the group III of species of Thyone (see above under the remarks for T. crassidisca ), in which the introvert ossicles show as both tables and rosettes. However, T. florianoi sp. nov. can be easily distinguished from the species from group III as follows. It differs from its western Atlantic congeners ( T. crassidisca and T. pseudofusus ) in lacking handles in the four-holed body wall tables ( Fig. 3A–B ), present in the later species.

Thyone florianoi sp. nov. differs from T. avennusta Cherbonnier, 1970 , T. bacescoi Cherbonnier, 1972 , T. cherbonnieri Reys, 1959 , T. dura Koehler & Vaney, 1908 , T. fusus (O. F Müller, 1776) , T. gadeana Perrier, R, 1898 , T. okeni Bell, 1884 , T. papuensis Théel, 1886 and T. pedata Semper, 1868 in possessing rosettes in the tentacles instead of rods; it differs from T. carens Cherbonnier, 1988 , T. roscovita Hérouard, 1889 , T. spinifera Liao in Liao & Clark, 1995 and T. vadosa Cherbonnier, 1988 in having tables in the body wall, whereas the latter species lack any kind of body wall ossicles.

Thyone florianoi sp. nov. can be distinguished from T. infusca Cherbonnier, 1954 by the presence of tables in the body wall, which are lacking in T. infusca ; it can be separated from Thyone deichmannae Madsen, 1941 , Thyone pohaiensis Liao, 1986 , T. purpureopunctata Liao & Pawson, 2001 and T. sinensis Liao & Pawson, 2001 in having quadrilocular tables in the body wall, instead of multilocular tables as in the latter species. Finally, T.

florianoi sp. nov. differs from T. micra Clark, 1938 in possessing high and tapering spires in the tube feet tables, whereas the tube feet tables have low spires ending in a crown of spines in T. micra .

Figures

FIGURE 3. (A–E) Thyone florianoi sp. nov., holotype (MZUSP 1351). (A) Specimen preserved in ethanol. (B) Calcareous ring. (C) Retractor muscle (black arrow) and insertion point of the muscle into the calcareous ring (white arrow). (D) Madreporite (black arrow) and stone canal (white arrow).(E) Polianvesicle (white arrow). Scale bars:A, 5 mm.B–C, 2.5 mm. D–E, 2 mm.

FIGURE 4. (A–I) Thyone florianoi sp. nov., holotype (MZUSP 1351). SEM images of the ossicles. (A) Body wall tables, lateral view. (B) Body wall tables, top of view. (C) Rosettes from tentacles, top view. (D) Tables from introvert, lateral view. (E) Tables from introvert, top view. (F) Tables from introvert, bottom view. (G)Supporting tables from tube feet, lateral view. (H) Plates from tube feet.(I) End plate from tube feet. Scale bars: A–B, 40 µm. C, 20 µm. D–F, 30 µm. G, 60 µm. H, 40 µm. I, 100 µm.