Psolus vitoriae Tommasi 1971

Psolus vitoriae Tommasi, 1971

(Figs. 1–2; Table 1)

Type material. Neotype, 8 mm (MZUSP 1632), Brazil, Vitória Island, São Paulo, 1.ii.1968, from depths between 50–100m (Tommasi, 1970; 1985).

Non type material. 1 spm, 8 mm (MZUSP 1633), same data as the neotype. 1 spm, 11 mm (MZUSP 749), REVIZEE, off coast of São Paulo, 24°20’S, 44°09’W, 10.i. 1998, 258m. 2 spms, 6–8 mm (MZUSP 746), off coast of São Paulo, 25°36’S, 45°13’W, REVIZEE, 13.i. 1998, 380m. 6 spms, 3–5 mm (MZUSP 594), São Paulo, no exact locality, depth and date. 1 spm, 7 mm (MZUSP 595), São Paulo, 3.i.1991, no exact locality and depth. 1 spm, 6 mm (MZUSP 745), REVIZEE, off coast of Rio Grande do Sul, 2.iv. 1998, 200m. 1 spm, 8 mm (MZUSP 763), REVIZEE, 10.i.1998, no exact locality, depth and date.

Type locality. Vitória Island, São Paulo, Brazil, between 50–100m.

Distribution. Southwestern coast of Brazil (São Paulo, Rio de Janeiro and Rio Grande do Sul), between 10 and 380m on gravel or muddy bottoms with dead shells (Tommasi, 1971; Moura, 2016; present paper).

Diagnosis. Body flat ventrally, convex dorsally. Dorsum covered by multi-layered, imbricating scales covered with granules. Five oral and anal valves, distinct from body wall scales. Calcareous ring with radial and interradial plates notched. Ventrolateral ambulacra with two rows of podia, tube feet ossicles comprised of perforated rods and end plates. Dorsal/lateral and sole ossicles smooth and knobbed perforated plates.

Description. Body flat ventrally, convex dorsally, 3–11 mm long up to 4–9 mm wide (Fig. 1A). Mouth and anus each surrounded by five triangular valves of equal size, anal valves smaller than oral valves (Fig. 1A, B), oral and anal teeth lacking. Body wall scales well demarcated from oral and anal openings. Dorsal and lateral body surfaces lacking tube feet, provided with conspicuous, imbricating scales (1.2 – 5 mm long, Fig. 1 A, C) covered with granules (Fig. 1A; 2A, B). Marginal dorsolateral scales smaller than dorsal scales (Fig. 1C). Sole thin, without scales. Ventrolateral ambulacra with an inner row of large tube feet, and outer row of small tube feet (Fig. 1D). Mid-ventral tube feet row absent. Eight Polian vesicles (just observed in the neotype) (Fig. 1D). Ten dendritic tentacles, eight large and two small ventrally. Calcareous ring (Fig. 1E, F) simple, lacking posterior processes; radial and interradial plates notched.

Dorsal/lateral and sole ossicles include curved perforated plates smooth in both ventral/dorsal sides (100–120 µm long), holes up to 20 µm in diameter (Fig. 2C) and Knobbed, perforated plates, irregular in outline, undulating margins (80–120 µm long) and rounded holes up to 20 µm in diameter (Fig. 2D). Tube feet supporting rods perforated, irregular in outline, curved, variably knobbed, (100–200 µm long) (Fig. 2E); end plates (up to 140 µm in diameter) with numerous small central holes and larger ones outside these (Fig. 2F).

Remarks. Psolus vitoriae was described by Tommasi (1971) based on eight specimens from off the coast of São Paulo, southeastern Brazil: four of which were collected from 50 m depth near Vitória Island, with another four specimens from 100 m at 25°05’S, 45°35’ W. Tommasi (1971) neither selected a holotype nor provided a type series. Therefore, all eight specimens should be regarded as syntypes. At the time of the original description of P. vitoriae he held a teaching/research position at the Oceanographic Institute, University of São Paulo, Brazil (IOUSP), where his collections were stored for many years. After Tommasi's retirement, he took his entire collections with him to FUNDESPA. Years later, most of what remained of his collections was transferred to MZUSP, although some (mostly ophiuroids) went to UNESP, UNICAMP and UFRJ. Our recent attempts to locate the type series of P. vitoriae at the IOUSP, MZUSP and other Brazilian collections (MNRJ, UNESP, UFRJ and ZUEC) were unsuccessful. Therefore, the specimen MZUSP 1632, collected at the type locality (Vitória Island, São Paulo) one year before the collection of part of the syntypes is herein designated as the neotype of P. vitoriae Tommasi, 1971.

In addition, we herein offer a re-description of the species to offset the poor illustrations and internally inconsistent description of the original. Psolus vitoriae reportedly possessed cups, but the illustrations show curved plates instead (Tommasi, 1971: 4, 17, Fig. 12E, F and H. See also Fig. 2C in the present paper). Likewise, the plates from the sole were described as smooth, while the illustrations depict knobbed plates (Tommasi, 1971: 4, 17, Fig. 12D, H and I. See also Fig. 2D in the present paper).

Psolus vitoriae can be distinguished from P. patagonicus by the morphology of the calcareous ring, with interradial plates notched in P. vitoriae (vs. not notched interradial plates in P. patagonicus). The two species can be further differentiated by the presence of granules over the dorsal scales in P. vitoriae (vs. naked dorsal scales in P. patagonicus).

Psolus vitoriae resembles P. antarcticus in having both the oral and anal valves distinct in size from the dorsal scales, 2 rows of ventral tube feet and granules on the dorsal scales. However, P. vitoriae differs from P. antarcticus in the numbers of dorsal scales between oral and anal valves (2 in P. vitoriae vs. 7– 9 P. antarcticus). Additionally, P. vitoriae has smooth, perforated plates in the dorsal and lateral scales and sole (vs. smooth, perforated plates absent in the dorsal and lateral body wall and sole in P. antarcticus).

Psolus vitoriae differs from Psolus murrayi Théel, 1886, P. lawrencei Martinez & Penchaszadeh, 2017, and P. segregatus Perrier, 1905, in having no midventral tube feet (vs. midventral tube feet present in the later two species). Psolus vitoriae further differs from P. lawrencei in having five, conspicuous, single layered oral and anal valves (vs. more than five, several layered oral and anal valves in P. lawrencei).