Idanthyrsus mexicanus Kirtley, 1994

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

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Idanthyrsus mexicanus Kirtley, 1994


Idanthyrsus mexicanus Kirtley, 1994  

Idanthyrsus mexicanus   in Kirtley 1994: 105-106, fig. 6.12.


Type status: Other material. Occurrence: catalogNumber: LEMA-PO158; recordedBy: Beatriz Yáñez-Rivera; individualCount: 6; 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: 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-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 GoogleMaps  


Gregarious worms commonly known as "honey comb worms". Tubes constructed with sea shells fragments, echinoderm spines debris, sand and small gravel (as well as I. cretus   ). Complete specimens 8-11.1 mm long, 1-2 mm wide, with 27-30 abdominal chaetigers and a caudal peduncle 2-3 mm long. Body divided into four specialised regions: operculum, parathorax (with three segments), abdomen and caudal region (Fig. 7 View Figure 7 A). Operculum composed by a crown and a peduncle, forming two not fused lobes. Median organ short, not longer than opercular lobes. Outer palea with straight blades; base of blades with transversal thecal fringes (Fig. 7 View Figure 7 E), lateral denticles straight (Fig. 7 View Figure 7 F), longer and narrower towards tips (Fig. 7 View Figure 7 G). Inner paleae straight with markedly, transversal thecae and pointed tips (Fig. 7 View Figure 7 H-J). A pair of nuchal hooks curved (Fig. 7 View Figure 7 B) without hoods or limbations on concave sides of hooks (Fig. 7 View Figure 7 C). Abdominal uncini with six pairs of teeth in side view (Fig. 7 View Figure 7 D).


This constitutes the fist record since its establishment by Kirtley (1994).

Taxon discussion

This species was described from Bahía Tenacatita, west of the islets off Barra de Navidad, between 45.7 and 64 m depth. A second species from Western Mexico is Idanthyrsus armatopsis   Fauchald, 1972 Fauchald (1972) described from bathyal depths (1200 -1400 m) in the Gulf of California. Idanthyrsus mexicanus   and I. armatopsis   shares the presence of nuchal hooks without hoods, but the inner paleae in I. mexicanus   have pointed tips versus blunt tips in I. armatopsis.   Number of teeth of abdominal uncini was not described by Kirtley (1994) to I. mexicanus   , but specimens here reported from Chamela Bay have six teeth in side view versus 7-8 teeth in I. armatopsis   . The median organ in I. mexicanus   (not described in original description by Kirtley 1994) is short, extending only 1/4 above lateral opercular lobes, whereas in I. armatopsis   , this organ extends 1/2 above lateral opercular lobes.














Idanthyrsus mexicanus Kirtley, 1994

Yanez-Rivera, Beatriz, Tovar-Hernandez, Maria Ana, Galvan-Villa, Cristian Moises & Rios-Jara, Eduardo 2020

Idanthyrsus mexicanus

Kirtley 1994