Idanthyrsus sp.

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 sp.

Idanthyrsus sp. considered as new to science by Chávez-López 2019: 37-45, figs 9-10.

Materials

Type status: Other material. Occurrence: catalogNumber: LEMA-PO159 ; recordedBy: Irving Ramírez-Santana; individualCount: 6; Location: higherGeographyID: Pacific Ocean; higherGeography: Tropical Eastern Pacific; continent: America; islandGroup: Islas de Chamela; island: Isla Cocinas; country: México; countryCode: MX; stateProvince: Jalisco; municipality: La Huerta; minimumDepthInMeters: 3; maximumDepthInMeters: 4; verbatimLatitude: 19°32 ’57’’ N; verbatimLongitude: 105°06 ’20’’ W; Identification: identifiedBy: María Ana Tovar-Hernández; Event: samplingProtocol: Snorkel; eventDate: April 23, 2009; year: 2009; month: 4; day: 23; habitat: Rock; fieldNumber: Site 1; 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" (as well as I. cretus and I. mexicanus ). Tubes constructed with sea shells fragments (Fig. 8 A). Complete specimens 14.1-14.5 mm long, 1.3-1.5 mm wide, with 26-32 abdominal chaetigers and a caudal peduncle 4-6 mm long. Body divided into four specialised regions: operculum, parathorax (with three segments), abdomen and caudal region where there is a long peduncle (Fig. 8 B). Operculum composed by a crown and a peduncle, forming two not fused lobes (Fig. 8 C). Outer paleae with straight blades basally, then slightly curved towards tips (Fig. 8 F); lateral denticles long, narrow and straight, those from the distal area longer than basal half (Fig. 8 F-G). Inner paleae with straight blades, transversal thecae not easily seen and pointed tips (Fig. 8 H). Two nuchal hooks with limbate area in concave sides (Fig. 8E). Abdominal uncini with seven teeth in side view (Fig. 8 D).

Ecology

Found in colony mixed with Idanthyrsus cretus .

Taxon discussion

Chávez-López (2019) recorded this species to Guerrero and Oaxaca and the formal description of the species is under construction ( Chávez-López pers. com. 2020). Specimen from Bahía de Chamela fits the description provided by Chávez-López (2019), except for the presence of inner paleae with pointed tips versus blunt by Chávez-López (2019). Judging from her Figure 9D, we considered that the tip is pointed instead of blunt. In addition, in her Figure 10G, an inner palea from a juvenile has a blunt tip, but it seems broken.

Figures

Figure 8. Idanthyrsus sp. A) Worm inside its tube, B) entire body, C) operculum, D) abdominal uncinus, E) nuchal hook, F) outer opercular paleae, G) radiolar tip of outer opercular palea, H) inner opercular palea. Scale bars: A, C) 2 mm, B) 3 mm, D, G-H) 1000 x magnification, E-F) 400 x magnification.