Themiste (Themiste) hennahi Gray 1828
Creators: name: Gómez-Vásquez, Julio D.
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Animalia
Sipuncula
Sipunculidea
Golfingiiformes
Themistidae
Themiste
Themiste hennahi

description: Themiste (Themiste) hennahi Gray, 1828
Fig. 6G
Themiste hennahi Gray, 1828: 8, pl.6 fig 4, 4a (type locality: Perú).
Dendrostoma mytheca Chamberlin, 1920: 30–31 (type locality: Laguna Beach California, on algae).
Dendrostoma zostericola Chamberlin, 1920: 30 (type locality: Laguna Beach, California, within algae).
Dendrostomum lissum Fisher, 1952: 419–422, pl. 35 (type locality: Punta Lobos, Espíritu Santo Island, Baja California Sur, intertidal).
Dendrostomum schmitti Fisher, 1952: 422, fig. 87f (type locality: Independencia Bay, Perú).
Dendrostma zostericola – Fisher 1952: 411–415, pl. 30 fig. 1, pls 31–32 (as Dendrostomum zostericolum; Ensenada, Baja California, intertidal, algal rhizoids, gravel and sand under rocks, and in muddy sand).
Themiste (Themiste) hennahi – Cutler & Cutler 1988: 742, 753–755, table 1 (new combination). — Silva-Morales & Gómez-Vásquez 2021: 86–88, fig. 5 (San Agustín Bay, Oaxaca, inhabiting Porites sp.).
Material examined
MEXICO – Baja California • 1 spec.; Los Ángeles Bay; 28°56ʹ55.48ʺ N, 113°33ʹ26.36ʺ W; 25 May 1989; SSV and JLG leg.; ECOSUR-S0255. – Nayarit • 21 specs; Banderas Bay, Manzanilla Beach; 20°44ʹ25.49ʺ N, 105°23ʹ24.33ʺ W; 29 Nov.2004; depth 2m; PSS et al. leg.; under rocks; ECOSUR-S0253. – Jalisco • 2 specs; Barra de Navidad, Corrales Beach; 19°11ʹ14.08ʺ N, 104°41ʹ42.84ʺ W; 3 Dec. 2004; depth 4 m; PSS et al. leg.; under rocks; ECOSUR-S0254.
Description
Trunk 6 mm in length, pyriform, caudal region nipple-like; smooth light brown body wall, with small, flat oval papillae. Introvert as long as trunk; tentacular crown with six stems, each one divided into two branches, branches with 10 terminal tentacles; tentacles pigmented in dark patches.
Longitudinal musculature continuous; two retractor muscles attached at 75% of trunk length; contractile vessel with 15 long tubules. Two nephridia 25% of trunk length; nephridiopores posterior to anus. Spindle muscle present, not attached to intestine posteriorly.
Variations
The specimens examined had a trunk length range between 2 and 12 mm. The number of tentacles varies with length, a specimen with a trunk length of 2 mm having eight terminal tentacles on each branch, while a specimen with a trunk length of 6 mm has 10 terminal tentacles on each branch of the tentacular crown; the largest specimen measured here has a trunk length of 12 mm and it has 14 terminal tentacles on each branch. Considering all specimens, the total amount of tentacles is between 72 and approximately 170.
Habitat
Intertidal to subtidal (4 m); under rocks, between algal rhizoids, in gravel and muddy sand.
Distribution
Eastern Pacific: from California to Perú.
Remarks
The specimens agree with the descriptions made by Gray (1828) and Fisher (1952). This species has previously been recorded from the study area in the Gulf of California.
description: Published as part of Gómez-Vásquez, Julio D., 2024, New records and five new species of sipunculans (Sipuncula) from the central and northwestern Mexican Pacific, pp. 179-219 in European Journal of Taxonomy 925 on pages 197-198, DOI: 10.5852/ejt.2024.925.2463, http://zenodo.org/record/10821775