Aspidosiphon (Paraspidosiphon) cutleri, Silva-Morales & Gómez-Vásquez, 2021

Silva-Morales, Itzahí & Gómez-Vásquez, Julio D., 2021, First records and two new species of sipunculans (Sipuncula) from the Southern Mexican Pacific, European Journal of Taxonomy 740 (1), pp. 77-117 : 99-101

Aspidosiphon (Paraspidosiphon) cutleri sp. nov.

urn:lsid:zoobank.org:act:48C0AFB4-02DD-4164-9223-BDA2CC1D0A43

Fig. 12

Etymology

In memory of Edward Cutler, expert in sipunculans and the principal source of inspiration for this work.

Material examined

Holotype MEXICO • Oaxaca, Camarón Beach ; 15°39′45″ N, 96°31′33″ W; 6 Apr. 2013; in dead coral; RXP and VAR leg.; UMAR-SIPU 082.

Paratypes MEXICO • 1; same locality as for holotype; 16 Nov. 2016; JGV leg.; depth 2 m, in rocks, UMAR-SIPU 083 • 1; Oaxaca, San Agustin Bay ; 15°41′21.1″ N, 96°14′11.1″ W; 18 Mar. 2018; depth 2 m, in rocks; UMAR-SIPU 107 .

Description

Trunk 30 mm in length, white ( Fig. 12A ). Anal and caudal shield brown. Sixteen longitudinal grooves in anal shield. Caudal shield also with grooves ( Fig. 12C–D ). Units of anal region distributed in longitudinal lines ( Fig. 12E ). More than 100 rings of unidentate proximal hooks, smaller than distal hooks ( Fig. 12F ) followed by scattered pyramidal hooks. Longitudinal muscles of body wall gathered into anastomosing bands. A pair of retractor muscles, fused for most of their length. Nephridia unilobed, occupying 50% of the trunk. Spindle muscle bifurcated near its anterior end ( Fig. 12B ).

Remarks

The species that are most similar to Aspidosiphon (Paraspidosiphon) cutleri sp. nov. are A. (P.) coyi de Quatrefages, 1865 , described from the Indian Ocean, and A. (P.) laevis de Quatrefages, 1865 . The type material of these two species was described by Saiz-Salinas (1983). The main differences between these species are the following: Aspidosiphon (P.) coyi has bidentate hooks and disperse units in the anterior region of the trunk; Aspidosiphon laevis lacks bidentate hooks and the units on the anterior region of the trunk are dispersed; nephridiopores are at the same level as the anus in both these species; on the other hand, A. (P.) cutleri sp. nov. only has unidentate hooks and the units are distributed in lines on the anterior region of the trunk; the nephridiopores are posterior to the anus. It is likely that the record of A. (P.) laevis from Costa Rica ( Dean et al. 2010) corresponds to this new species; however, it is necessary to review the specimens.

Habitat

Subtidal (2 m); in dead coral.

Distribution

Oaxaca, Mexico.

Figures

Fig. 12. Aspidosiphon (Aspidosiphon) cutleri sp. nov., holotype (UMAR-SIPU 082), from the Southern Mexican Pacific. A. External morphology. B. Internal morphology. C. Anal shield, dorsolateral view. D. Anal shield, dorsal view. E. Anal shield, lateral view. F. Distal unidentate hooks. Abbreviations: I = intestine; LM = longitudinal muscle; N = nephridium; RM = retractor muscles.