Idanthyrsus cretus Chamberlin, 1919

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

Idanthyrsus cretus Chamberlin, 1919

Idanthyrsus cretus Chamberlin, 1919 Chamberlin 1919: 485-487, pt. 76, figs. 8-15.

Idanthyrsus pennatus (not Peters 1854).- Monro 1933: 1063, fig. 13.- Rioja 1942: 155-157, figs. 1-14.- Hartman 1944a: 336, pt. 31, fig. 35.- Berkeley and Berkeley 1958: 405.- Rioja 1959: 255.- Rioja 1962: 199.- Fauchald 1977: 54.- Salazar-Vallejo et al. 1990: 213, fig. 6.- Bastida-Zavala 1993: 12, 14, 32.- Bastida-Zavala 1995: 22.

Idanthyrsus cretus .- Kirtley 1994: 95-96, fig. 6.6.- Gómez et al. 1997: 1070.- Hernández-Alcántara et al. 2003: 9.- Chávez-López and Cruz-Gómez 2019: 5, 8, fig. 2E.- Chávez-López 2019: 21-28, figs. 2H-I, K, 5-6.

Materials

Type status: Other material. Occurrence: catalogNumber: LEMA-PO156 ; recordedBy: Beatriz Yáñez-Rivera; individualCount: 1; Taxon: phylum: Annelida; class: Polychaeta; order: Sabellida; family: Sabellariidae; genus: Idanthyrsus; 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: 4; verbatimLatitude: 19°33 ’22’’ N; verbatimLongitude: 105°06 ’50’’ W; Identification: identifiedBy: María Ana Tovar-Hernández; Event: samplingProtocol: Scuba dive; eventDate: June 25, 2013; year: 2013; month: 6; day: 25; habitat: On rock; 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 Type status: Other material. Occurrence: catalogNumber: LEMA-PO157 ; recordedBy: Beatriz Yáñez-Rivera; individualCount: 4; Taxon: phylum: Annelida; class: Polychaeta; order: Sabellida; family: Sabellariidae; genus: Idanthyrsus; 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: 4; verbatimLatitude: 19°33 ’29’’ N; verbatimLongitude: 105°06 ’40’’ W; Identification: identifiedBy: María Ana Tovar-Hernández; Event: samplingProtocol: Snorkel; eventDate: June 27, 2013; year: 2013; month: 6; day: 27; habitat: On coral; fieldNumber: Site 2; Record Level: language: Spanish; institutionID: Universidad de Guadalajara; collectionID: Colección Biológica del Laboratorio de Ecosistemas Marinos y Acuicultura; institutionCode: UDG; collectionCode: LEMA

Description

Gregarious worms commonly known as "honey comb worms". Tubes constructed with sea shells fragments, echinoderm spines debris, sand and small gravel. Complete specimens 13-29 mm long, 2-4 mm wide, with 22-31 abdominal chaetigers and a caudal peduncle 3-5 mm long. Body divided into four specialised regions: operculum, parathorax (with three segments), abdomen and caudal region (Fig. 6 A-B). Operculum composed of a crown and a peduncle, forming two not fused lobes (Fig. 6 E). Outer paleae with blades curved distally and lateral denticles curved (Fig. 6 G). Inner paleae with straight blades, smooth and blunt tips (Fig. 6 H). A pair of nuchal hooks with limbation or hood below the concave area (Fig. 6 F). Uncini with six pairs of teeth (Fig. 6 C-D).

Distribution

Idanthyrsus cretus is a widely-reported species from Isla Cedros (Baja California, Mexico) to Ecuador, including the Galapagos Islands ( Bastida-Zavala and Becerrill-Tinoco 2009).

Taxon discussion

Detailed description and illustrations are available in Kirtley (1994).

Figures

Figure 6. Idanthyrsus cretus Chamberlin, 1919. A) Entire worm, dorsal view, B) same, ventral view, C) abdominal uncinus dentition, lateral view, D) abdominal uncini, E) operculum and parathorax, F) nuchal hook, G) outer opercular paleae, H) inner opercular paleae. Scale bars: A) 2 mm, B, E) 4 mm, C) 1000 x magnification, D, G-H) 400 x magnification, F) 0.25 mm.