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

Gómez-Vásquez, Julio D., 2024, New records and five new species of sipunculans (Sipuncula) from the central and northwestern Mexican Pacific, European Journal of Taxonomy 925, pp. 179-219 : 190-191

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

Fig. 3D–F

Aspidosiphon (Paraspidosiphon) pastori Silva-Morales & Gómez-Vásquez, 2021: 101–103 , fig. 13 (type locality: Panteón Beach, Puerto Ángel, Oaxaca).

Material examined

MEXICO – Baja California • 12 specs; Cabo San Miguel ; 28°10ʹ00ʺ N, 112°47ʹ07ʺ W; 13 Mar. 1985; depth 29–35 m; trawl; Cortés II stn 19, on board R/V El Puma; EMU-13433 • 10 specs; Cabo San Miguel ; 28°10ʹ00ʺ N, 112°47ʹ07ʺ W; 13 Mar. 1985; depth 25–29 m; trawl; Cortés II stn 19, on board R/V El Puma; UMAR-SIPU 153 • 3 specs; Cabo San Miguel ; 28°09ʹ04ʺ N, 112°46ʹ06ʺ W; 1 Aug. 1982; depth 30–35 m; Van Veen grab; Cortés III stn 20, on board R/V El Puma; EMU-13434 . – Baja California Sur • 4 specs; La Paz , Cabo Pulmo ; 1989; UMAR-SIPU 154 • 1 spec.; La Paz, El Caimancito Beach ; 24°12ʹ10.43ʺ N, 110°18ʹ01.09ʺ W; 10 Oct. 1987; depth 2 m; SSV leg.; in rocks; ECOSUR-S0286 • 4 specs; La Paz , El Caimancito Beach ; 24°12ʹ15ʺ N, 110°18ʹ02.96ʺ W; 29 Feb. 2004; depth 1 m; PSS and MTH leg.; inhabiting Porites sp. ; ECOSUR-S0283 • 1 spec.; Calerita Beach ; 1 Mar. 2006; DHP et al. leg.; intertidal; UMAR-SIPU 155 . – Sinaloa • 2 specs; Mazatlán Bay ; 28 Oct. 1980; Crucero 15, stn 8; EMU-13435 . – Nayarit • 3 specs; Sayulita Beach ; 20°47ʹ24ʺ N, 105°31ʹ54ʺ W; 10 Apr. 1996; depth 2 m; under rocks; UMAR-SIPU 156 • 2 specs; Banderas Bay, Manzanilla Beach , 20°44ʹ25.49ʺ N, 105°32ʹ24.33ʺ W; 29 Nov. 2004; depth 2 m; PSS et al. leg.; in rocks; ECOSURS0282 . – Jalisco • 2 specs; San Patricio Melaque Beach ; 19°13ʹ08.82ʺ N, 104°42ʹ50.22ʺ W; 1 Dec. 2004; depth 1 m; PSS et al. leg.; in rocks; ECOSUR-S0287 • 1 spec.; San Patricio Melaque Beach ; 19°13ʹ12.08ʺ N, 104°42ʹ49.95ʺ W; 2 Dec. 2004; depth 3 m; PSS et al. leg.; in rocks; ECOSUR-S0285 • 8 specs; Barra de Navidad, Corrales Beach ; 19°11ʹ14.08ʺ N, 104°41ʹ42.84ʺ W; 3 Dec. 2004; depth 4 m; PSS et al. leg.; in rocks; ECOSUR-S0284 . – Michoacán • 1 spec.; Caleta de Campos ; 17 Dec. 1994; MSGM and RBZ leg.; UMAR-SIPU 157 • 1 spec.; Bucerías Beach ; 19 Dec. 1994; MSGM and RBZ leg.; UMAR-SIPU 158 .

Description ( UMAR-SIPU 154)

Trunk 10 mm in length; whitish semi-translucent ( Fig. 3D ). Introvert as long as trunk. Six small digitiform tentacles surrounding nuchal organ. Anterior 40% of introvert length with laterally compressed bidentate hooks ( Fig. 3E ), 20 µm long, arranged in rings; scattered pale pyramidal hooks on rest of introvert, 30 µm long ( Fig. 3F ). Anal shield consisting of small dark, packed granules with diffuse margins. Caudal shield of same shape as anal shield, with diffuse margins.

Longitudinal musculature divided in 18 bands along trunk, with high degree of anastomosis. Two retractor muscles attached to body wall at 95% of trunk length. Nephridia 25% of trunk length; spindle muscle attached intestine at both ends of trunk.

Habitat

Intertidal to subtidal (35 m). In dead coral ( Porites sp. ).

Distribution

Mexican Pacific: from Gulf of California to Oaxaca.

Remarks

This species was recently described from the southern Mexican Pacific. The specimens from the central and northwestern Mexican Pacific coincide with the description made by Silva-Morales & Gómez-Vásquez (2021); with this study the range extends from Guerrero State (southern Mexican Pacific) to the Gulf of California.

The specimens of Aspidosiphon (P.) pastori are morphologically close to A. (P.) tenuis Sluiter, 1886. The main differences are present in the proximal hooks. In A. (P.) pastori the pyramidal hooks are pale, whereas A. (P.) tenuis instead has unidentate structures with laterally reinforced ridges ( Cutler 1994). Another difference is that A. (P.) pastori has a shield made of granules with diffuse margins, and A. (P.) tenuis has a grooved shield with well-defined margins.

Figures

Fig. 3. Aspidosiphonids. A–C. Aspidosiphon (Aspidosiphon) elegans (Chamisso & Eysenhardt, 1821 (UMAR-SIPU 151). A. Lateral overview of specimen with budding. B. Anterior bidentate hook. C. Posterior conical hook. D–F. Aspidosiphon (Paraspidosiphon) pastori Silva-Morales & Gómez- Vásquez, 2021 (UMAR-SIPU 154).D. Lateral overview, introvert partially everted.E. Anterior bidentate hook. F. Posterior pyramidal hook. Bd = bud. Scale bars: A, D = 3 mm; B–C = 20 µm; E–F = 10 µm.