Apionsoma (Apionsoma) hespera ( Chamberlin, 1920 ), 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 : 93-95

publication ID	https://doi.org/10.5852/ejt.2021.740.1283
publication LSID	lsid:zoobank.org:pub:07F1B593-9F4F-4B32-88D9-ADC5CA0BEB84
DOI	https://doi.org/10.5281/zenodo.4644412
persistent identifier	https://treatment.plazi.org/id/03CA87A4-D360-8030-7923-4572FAAC616E
treatment provided by	Plazi (2021-03-29 06:54:26, last updated by Guilherme 2024-12-09 17:50:24)
scientific name	Apionsoma (Apionsoma) hespera ( Chamberlin, 1920 )
status	comb. nov.

Treatment

Apionsoma (Apionsoma) hespera ( Chamberlin, 1920) View in CoL comb. nov., reinstatement

Figs 8A–C View Fig , 9 View Fig

Phascolosoma hespera Chamberlin, 1920: 31 View in CoL (type locality: Balboa, Newport Bay, Orange County, California).

Golfingia hespera – Fisher 1952: 393–395, pl. 24, figs 1–5 (San Lucas Cove, southern Santa Rosalía, Gulf of California, commensals in Cerianthus Delle Chiaje, 1841 tubes; Balboa, Newport Bay, Orange County, California).

Golfingia (Mitosiphon) hespera – Amor 1975: 115–116, pl. 2, figs a–d (Ancón, Peru in Phragmatopoma Mörch, 1863 and Perumytilus Olsson, 1961 , in rocks).

Material examined

MEXICO – Oaxaca • 1; Chacahua ; 15°58′07″ N, 97°32′09″ W; 4 Apr. 4, 2007; artificial monticule, in rocks; UMAR-SIPU 101 GoogleMaps • 3; Panteón Beach ; 15°39′50″ N, 96°29′42″ W; 24 Apr. 2012; NVHH leg.; UMAR-SIPU 102 GoogleMaps .

Description

Trunk 8 mm in length, spindle-shaped ( Fig. 9A View Fig ). Introvert seven times trunk length. Posterior end of trunk with numerous distinctive papillae ( Fig. 9C–D View Fig ). More than 40 rings of hooks, with 7–8 basal spinelets. Spinelets longer than principal tooth ( Fig. 9E View Fig ). Body wall with continuous muscle layers. Four retractor muscles equidistant from ventral nerve cord near middle of trunk. Nephridia bilobed, with

unequal lobules occupying almost 90% of trunk length ( Fig. 9B View Fig ). Spindle muscle attached to body wall posteriorly.

Remarks

We reinstate the name Phascolosoma hespera in the correct genus as the new combination Apionsoma (Apionsoma) hespera . The most similar species to A. (A.) hespera comb. nov. is A. (A.) misakianum ( Ikeda, 1904) from Misaki, Japan ( Table 4 View Table 4 ). Fisher (1952) illustrated type material and he showed the morphological and ecological differences between the two species. Cutler (1979) considered Phascolosoma hespera Chamberlin, 1920 and Golfingia hespera sensu Fisher 1952 as synonyms of A. (A.) misakianum , but we believe that the morphological features are enough to consider P. hespera as a valid name with a distribution in the TEP. We compared the illustrations of the hooks of A. (A.) misakinaum , from Misaki ( Ikeda 1904; Fig. 8D View Fig ) and other localities of Japan ( Cutler et al. 1984: 300–301; Fig. 8E View Fig ), with the hooks of the specimens revised in this study ( Fig. 8A View Fig ) and those of specimens recorded from Peru as Golfingia (Mitosiphon) hespera ( Amor 1975; Fig. 8B–C View Fig ). Staton & Rice (1999) stated that there is strong reproductive isolation between the northern and southern populations of the A. misakianum species complex, another argument to consider that A. hespera is a valid species and likely could be part of this species complex.

Habitat

Intertidal, in Cerianthus tubes, in rocks with Phragmatopoma and Perumytilus .

Distribution

Laguna Beach, California; Tropical Eastern Pacific from Baja California Sur to Oaxaca; Ancón, Peru.

References

Amor A. 1975. Notas sobre Sipuncula de la Argentina, Brasil y Peru. Physys 34: 113 - 120.

Chamberlin R. V. 1920. Notes on the sipunculids of Laguna Beach. Journal of Entomology and Zoology 12: 30 - 31.

Cutler E. B. 1979. A reconsideration of the Golfingia subgenera Fisherana Stephen, Mitosiphon Fisher, and Apionsoma Sluiter (Sipuncula). Zoological Journal of the Linnean Society 65: 367 - 384. https: // doi. org / 10.1111 / j. 1096 - 3642.1979. tb 01101. x

Cutler E. B., Cutler N. J. & Nishikawa T. 1984. The Sipuncula of Japan: their systematics and distribution. Publications of the Seto Marine Biological Laboratory 29 (4 / 6): 249 - 322.

Fisher W. K. 1952. The sipunculid worms of California and Baja California. Proceedings of the United States National Museum 102 (3306): 371 - 450. https: // doi. org / 10.5479 / si. 00963801.102 - 3306.371

Ikeda I. 1904. The Gephyrea of Japan. Journal of the College of Science, Imperial University of Tokyo 20: 1 - 87.

Sluiter C. P. 1902. Die Sipunculiden und Echiuriden der Siboga Expedition, nebst Zusammenstellung der ueberdies aus dem indischen Archipel bekannten Arten. Siboga Expeditie 25: 1 - 53. Available from https: // www. biodiversitylibrary. org / page / 2046852 [accessed 4 Mar. 2021].

Staton J. & Rice M. E. 1999. Genetic differentiation despite teleplanic larval dispersal: allozyme variation in sipunculans of the Apionsoma misakianum species complex. Bulletin of Marine Science 65: 467 - 80.

Figures

Fig. 8. – A–C. Hooks of Apionsoma (Apionsoma) hespera (Chamberlin, 1920) comb. nov. A. From Oaxaca, Mexico. B–C. From Peru. – D–E. Hooks of Apionsoma misakianum (Ikeda, 1904). D. From Misaki, Japan. E. From Japan. B–C: from Amor (1975); D: from Ikeda (1904); E: from Cutler et al. (1984).

Fig. 9. Apionsoma (Apionsoma) hespera (Chamberlin, 1920) comb. nov. from the Southern Mexican Pacific. A. External morphology. B. Internal morphology. C. Caudal papillae. D. Caudal papillae, amplified view. E. Hooks. Abbreviations: DRM = dorsal retractor muscles; I = intestine; LM = longitudinal muscle; N = nephridium; VRM = ventral retractor muscles.