Acromegalomma circumspectum (Moore, 1923)

Yanez-Rivera, Beatriz, Tovar-Hernandez, Maria Ana, Galvan-Villa, Cristian Moises & Rios-Jara, Eduardo, 2020, Tubicolous polychaete worms (Annelida) from Bahia de Chamela Islands Sanctuary, Mexico, with the description of a new bamboo worm, Biodiversity Data Journal 8, pp. 57572-57572 : 57572

Acromegalomma circumspectum (Moore, 1923)

Branchiomma circumspectum Moore, 1923 in Moore 1923: 239-241, pl. 18, figs. 41-42.

Megalomma circumspectum .- Hartman 1959: 550.- Hartman 1961: 43.- Hartman 1969: 707, figs 1-6.- Rioja 1962: 213-216, figs 145-148.- Fauchald 1972: 33.- Perkins 1984: 363.- Knight-Jones 1997: 314.- Hernández-Alcántara and Solís-Weiss 1999: 29.- Tovar-Hernández and Carrera-Parra 2011: 19-24, figs 4A-J, 6A-V, 28A, G, 29A.

Acromegalomma circumspectum .- Tovar-Hernández et al. 2019: 5, fig. 3A-B.

Materials

Type status: Other material. Occurrence: catalogNumber: LEMA-PO160 ; recordedBy: Beatriz Yáñez-Rivera; individualCount: 1; lifeStage: Adult; reproductiveCondition: Ripe; Taxon: phylum: Annelida; class: Polychaeta; order: Sabellida; family: Sabellidae; genus: Acromegalomma; Location: higherGeographyID: Pacific Ocean; higherGeography: Tropical Eastern Pacific; continent: America; islandGroup: Islas de Chamela; country: México; countryCode: MX; stateProvince: Jalisco; municipality: La Huerta; locality: Canal San Pedro ; maximumDepthInMeters: 5; verbatimLatitude: 19°32 ’01’’ N; verbatimLongitude: 105°05 ’17’’ W; Identification: identifiedBy: María Ana Tovar-Hernández; Event: samplingProtocol: Scuba dive; eventDate: June 26, 2013; year: 2013; month: 6; day: 26; habitat: On rock; fieldNumber: Site 7; Record Level: institutionID: Universidad de Guadalajara; collectionID: Colección Biológica del Laboratorio de Ecosistemas Marinos y Acuicultura; institutionCode: UDG; collectionCode: LEMA Type status: Other material. Occurrence: catalogNumber: LEMA-PO161 ; recordedBy: Beatriz Yáñez-Rivera; individualCount: 3; lifeStage: Adult; reproductiveCondition: Ripe; Taxon: phylum: Annelida; class: Polychaeta; order: Sabellida; family: Sabellidae; genus: Acromegalomma; Location: higherGeographyID: Pacific Ocean; higherGeography: Tropical Eastern Pacific; continent: America; islandGroup: Islas de Chamela; island: Isla Pajarera; country: México; countryCode: MX; stateProvince: Jalisco; municipality: La Huerta; maximumDepthInMeters: 7; verbatimLatitude: 19°33 ’22’’ N; verbatimLongitude: 105°06 ’50’’ W; Identification: identifiedBy: María Ana Tovar-Hernández; Event: samplingProtocol: Scuba dive; eventDate: June 26, 2013; year: 2013; month: 6; day: 26; habitat: On rock and coral; fieldNumber: Site 21; Record Level: language: Spanish; institutionID: Universidad de Guadalajara; collectionID: Colección Biológica del Laboratorio de Ecosistemas Marinos y Acuicultura; institutionCode: UDG; collectionCode: LEMA

Description

Complete specimens 10-19 mm long, 0.8-1.3 mm wide with 8 thoracic chaetigers and 42-61 abdominal chaetigers. Radiolar crown with 13-16 pairs of radioles. Radioles with subdistal eyes in most radioles, spherical. Those from dorsal-most radioles are the largest (Fig. 9 A-C1), then gradually decreasing their size towards lateral and some ventral radioles (Fig. 9 A-B). Ventral-most radioles with ocular spots (lacking ommatidia) (Fig. 9 C2). Dorsal margins of collar fused to faecal groove. A triangular keel present, projecting ventrally between dorsal lips (Fig. 9 E). Dorsal pockets present (Fig. 9 E). Length of thoracic tori is the same in all segments and not contacting the lateral margins of ventral shields (Fig. 9 D).

Taxon discussion

Widely reported in the Gulf of California and Nayarit ( Tovar-Hernández and Carrera-Parra 2011), this worm has been found being parasitised by Gastrodelphys dalesi , a cyclopoid copepod attached to the radioles, the inner base of the radiolar crown, dorsal lips and attached to the dorsal pockets of collar ( Gómez and Tovar-Hernández 2008). A full description and illustrations are available in the revision by Tovar-Hernández and Carrera-Parra (2011).

Figures

Figure 9. Acromegalomma circumspectum (Moore, 1923). A) Radiolar crown, dorsal view, B) compound radiolar eyes, C 1) eye from dorsal-most radiole showing their ommatidia, C 2) ocular spot from ventral-most radiole, D) thorax and anterior abdomen anterior, ventral view (crown removed), E) thorax, dorsal view (crown removed). Scale bars: A, D-E) 4 mm, B) 0.5 mm, C 1 - C 2) 0.3 mm.