Idanthyrsus bastidai, Chávez-López, 2021

Chávez-López, Yessica, 2021, Sabellariids (Annelida: Sedentaria: Sabellariidae) from shallow waters of the Gulf of Mexico and the Caribbean Sea, including three new species, Zootaxa 5048 (2), pp. 191-214 : 195

publication ID

https://doi.org/ 10.11646/zootaxa.5048.2.3

publication LSID

lsid:zoobank.org:pub:CBD94592-5647-4F52-A8CF-4990DE8574D8

DOI

https://doi.org/10.5281/zenodo.5555029

persistent identifier

https://treatment.plazi.org/id/03D0AE23-5162-FFD3-FF73-FF54FAA8106C

treatment provided by

Plazi

scientific name

Idanthyrsus bastidai
status

sp. nov.

Idanthyrsus bastidai View in CoL n. sp.

Figures 1A–F View FIGURE 1 ; 2A–G View FIGURE 2

LSID: urn:lsid:zoobank.org:act:2D4701B1-FC70-4B65-8CCB-456DC980120D

Material examined. Venezuela. Holotype (ECOSUR-250), Cumaná Turpialito , on Millepora , 1.5 m, February 22, 2002, coll. I. Liñero-Arana). Thirty-eight paratypes (ECOSUR-251), Cumaná, Turpialito, same data as for the holotype.

Description. Holotype complete (ECOSUR-250), mature female. Body colorless, 11 mm long, 2 mm wide, with three parathoracic segments, 28 abdominal segments, caudal peduncle 3 mm long ( Fig. 1 View FIGURE 1 ).

Opercular crown and opercular stalk completely divided into two lobes ( Fig. 1A–B View FIGURE 1 ). Opercular disc oblique, two rows of light amber paleae; outer row with 25 paleae per lobe, inner row with ~18 paleae per lobe. Outer paleae straight, marginal spines long, thin, progressively larger distally; 20–30 pairs of lateral spines. Paleal anterior region with compact thecae with irregular margins. Blade slightly inclined at an angle of 170° ( Fig. 2A–B View FIGURE 2 ). Inner paleae cylindrical, slightly inclined, tapered; blade with transverse thecae ( Fig. 2C View FIGURE 2 ); tip smooth, blunt ( Fig. 2D View FIGURE 2 ).

Opercular peduncle colorless ( Fig. 1A–C View FIGURE 1 ). Two amber nuchal hooks on the left lobe, one hook on the right ( Fig. 1B View FIGURE 1 ). Nuchal hooks falcate, with long limbation, tip sharp ( Fig. 2H View FIGURE 2 ). Tentacles and palps colorless. Median ridge as long as opercular stalk, with marginal brown eyespots. Median organ small, conical, colorless, without eyespots ( Fig. 1E View FIGURE 1 ). Building organ with small brownish spots.

Thorax without notochaetae. Chaetiger 1 with a pair of neuropodia bearing capillary, pinnate chaetae. Chaetiger 2 with capillary neurochaetae, a pair of lateral small cirri, and branchiae.

Parathorax colorless with three segments, all with paired branchiae ( Fig. 1C–D View FIGURE 1 ). Notopodia with six lanceolate and seven pectinate chaetae. Neurochaetae lanceolate and capillaries, thinner than notochaetae.

Abdominal segments colorless, with a pair of branchiae decreasing in size towards segment 16. Neuropodia with verticillate chaetae ( Fig. 2E View FIGURE 2 ). Notopodia with a series of uncini with 6–7 transverse rows of teeth ( Fig. 2F View FIGURE 2 ). Abdominal segment eight with longer neurochaetae ( Fig. 1F View FIGURE 1 ). Caudal peduncle cylindrical, colorless ( Fig. 1A View FIGURE 1 ).

Variation. Body 4–12 mm in total length, 0.8–2 mm wide, 18–33 abdominal segments, caudal peduncle 1–4 mm. Opercular crown made of 10–33 outer paleae per lobe, and 8–19 inner paleae per lobe. Almost all specimens with one pair of hooks ( Fig. 2H View FIGURE 2 ), except for five bearing an extra hook on one side, including the holotype.

One paratype specimen with fragments of the tube made of coarse sand ( Fig. 2G View FIGURE 2 ).

Etymology. This species is named after Dr. J. Rolando Bastida Zavala, for being a great mentor and teaching me about the world of polychaetes. The species name is a noun in the genitive case ( ICZN 1999, Art. 31.1.2).

Distribution. Turpialito, Cumaná, Venezuela at 1.5 m depth. Associated with Millepora corals.

Remarks. Idanthyrsus bastidai n. sp. closely resembles Idanthyrsus sp. fide Chávez-López (2019) from Guerrero, Mexico. Both species have outer paleae with long, thin, straight spines; however, Idanthyrsus sp. has completely straight outer paleae and blunt nuchal hooks ( Chávez-López 2019: Fig. 9C, F View FIGURE 9 ) with limbation shorter than that in I. bastidai n. sp. that is characterized by slightly bent outer paleae ( Fig. 2A–B View FIGURE 2 ) and sharp nuchal hooks ( Fig. 2H View FIGURE 2 ).

The coloration pattern also differs in both species, while Idanthyrsus sp. has the opercular peduncle and thorax strongly pigmented ( Chávez-López 2019), I. bastidai n. sp. lacks apparent pigmentation ( Fig. 1A–C View FIGURE 1 ).

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