Pomatostegus kroyeri Mörch, 1863

Sánchez-Ovando, J. Pablo & Bastida-Zavala, J. Rolando, 2021, Redescription of Pomatostegus stellatus (Abildgaard, 1789) and P. kroyeri Mörch 1863 (Polychaeta: Serpulidae) from the Tropical American coasts, Zootaxa 4970 (3), pp. 495-514 : 504-506

Pomatostegus kroyeri Mörch, 1863

( Figures 3A–D , 4A–E , 5C–D , 6D–F , 8B , 9 )

Pomatostegus krØyeri Mörch, 1863: 399 , pl. 11, Fig. 15. Type locality: Puntarenas, Costa Rica (re-identification of Grube’s material, below).

Serpula stellata (not Abildgaard, 1789).— Grube 1859: 113–114 (Puntarenas, Costa Rica); Salazar-Vallejo & Londoño-Mesa 2004: 55 (Tropical Eastern Pacific, checklist).

Serpula stellatus (not Abildgaard, 1789).— Dean 2004: 165 (referring to Grube 1859, above).

Pomatostegus kröyeri .— Dean 2004: 165 (list of polychaetes from Costa Rica).

Pomatostegus krØyeri .—ten Hove & Kupriyanova 2009: 78 (worldwide serpulid checklist).

Pomatostegus kroyeri .— Bastida-Zavala et al. 2016: 428–429 , fig. 12H (Marina San Carlos, Sonora; Margarita Island, Magdalena Bay and Caleritas Beach, Baja California Sur; Caleta de Chón, Guerrero; 6 m; off Centro Mexicano de la Tortuga Aquarium, Mazunte, San Agustinillo, Camarón Beach, Puerto Ángel, San Agustín Beach and Montosa Island, Oaxaca; 2–6 m; on mollusk shell, rocks and coral Pocillopora damicornis (Linnaeus, 1758)) ; Bastida-Zavala & Sánchez-Ovando 2021: 26 (identification key for Tropical American coasts).

Pomatostegus stellatus (not Abildgaard, 1789).— Monro 1928: 100 (Taboga Island, Panamá, 7–9 m, sand and stones); Monro 1933: 1081 (Balboa, Taboga and Coiba Islands, Panamá, intertidal to 18 m, on docks, pools at low tide and in sand); Treadwell 1937: 157 (Arena Bank, Gulf of California, 23°29’N, 109°23’30”W; 91 m); Fauvel 1943: 30 (Cabo Pulmo, Baja California Sur); Laverde-Castillo 1986: 128 (Málaga Bay, Colombian Pacific); Laverde-Castillo 1988: 91 (Curichichi Island, Málaga Bay, on dead coral and rocks); Salcedo-Martínez et al. 1988: 84 (Zihuatanejo, Guerrero); Salazar-Vallejo 1989: 200 (Mexican coasts, checklist); Bastida-Zavala 1995: 25 (Cabo Pulmo Reef, Baja California Sur, on coral; 4–17 m); Gómez et al. 1997: 1071 (Tangolunda and La Entrega beaches, Oaxaca; rocks and coral); López-García et al. 1997: 66 (Coiba Island, Panamá; under rocks); Hernández-Alcántara et al. 2003: 9 (checklist; erroneously cited from Cedros Island, Baja California; misquote of Treadwell’s record of 1937, above); Salazar-Vallejo & Londoño-Mesa 2004: 55 (Tropical Eastern Pacific, checklist); Bastida-Zavala 2008: 34 , fig. 7S (Cabo Pulmo Reef and Loreto Marina, Baja California Sur; 0–17 m); Bastida-Zavala 2009: 531 (identification key for Tropical American coasts); Bastida-Zavala et al. 2013: 349 (Oaxaca, checklist).

Material examined. 11 specimens.

Baja California Sur: (Total: 3 spec.), UMAR-Poly 789, 2 spec., (Margarita Island, Magdalena Bay , February 23, 1989, coll. R. Bastida-Zavala) ; UMAR-Poly 790, 1 spec., ( Caleritas Beach , on coral, March 10, 2006, coll. D. Herrero-Pérezrul et al., fixed and preserved in alcohol 96%) .

Guerrero: (Total: 1 spec.), UMAR-Poly 791, 1 spec. ( Caleta de Chón , 6 m, on coral Pocillopora damicornis , December 2, 2010, coll. S. Guendolain) .

Oaxaca: (Total: 6 spec.), UMAR-Poly 792, 1 spec. (off Centro Mexicano de la Tortuga Aquarium , Mazunte, 2 m, on rock, June 11, 2013, coll. T. Peregrino & C. Valeriano); UMAR-Poly 793, 1 spec. (San Agustinillo, on mollusk shell, May 11, 2013, coll. A. Gerónimo et al.); UMAR-Poly 794, 1 spec. (Camarón Beach, on coral, April 27, 2013, coll. R. Xavier & V. Alvarado); UMAR-Poly 795, 1 spec. (Puerto Ángel, on rocks, May 3, 2010, coll. H. Sánchez & A. Pineda); UMAR-Poly 796, 1 spec. (San Agustín Beach, 5.8 m, on coral Pocillopora damicornis , February 23, 2010, coll. R. Granja & S. Guendolain); UMAR-Poly 797, 1 spec. (Montosa Island, 6 m, on P. damicornis , February 22, 2010, coll. R. Granja & S. Guendolain) .

Costa Rica: (Total: 1 spec.), UMAR-Poly 835, 1 spec. ( Cabo Blanco , Puntarenas, intertidal zone, between basalts, November 10, 2012, coll. T. F. Villalobos-Guerrero, fixed and preserved in alcohol 96%) .

Redescription. Tube with five longitudinal ridges, the middle largest, forming an elevated crest, outer tube surface of brown color, inner surface of white color, semi-circular in cross-section ( Fig. 8B ). Body yellowish, 40 mm long ( Fig. 3D ). Thorax 5 mm long and 3.1 mm wide, with seven chaetigers. Abdomen with 106 chaetigers. Radioles with 1–3 bands of black-blue iridescent pigment ( Fig. 3B ). Opercular peduncle maculated with black-blue pigment, 10 mm long including opercular plates and 3 mm wide in the basal plate; with wide wings; inserted into right lobe ( Fig. 3B–C ). Operculum chitinous, 4 mm long; with three concentric festooned deep dish-shaped plates, successive plates barely separated, connected to a hollow column with a tip with one “free” circlet of spines without accompanying plates; circlets of small spines present at the basis of each plate (immediately below each plate; Fig. 3A–D ). Thoracic membrane short, extending to segment 3. Collar chaetae missing at both sides in examined specimen ( Costa Rica, UMAR-Poly 835); other specimens with Spirobranchus - type chaetae with a narrow proximal boss. Thoracic chaetigers with two kinds of chaetae, Apomatus - type and limbate ( Fig. 4A–B ). Abdominal chaetae flat narrow geniculate, with long blade ( Fig. 4C ). Thoracic uncini of segment 5 saw-shaped, with 10–11 teeth ( Fig. 4D ). Abdominal uncini similar to thoracic uncini but smaller, with 7–8 teeth ( Fig. 4E ).

Variability. Tubes brown to white, with five longitudinal ridges. Body length variable (n=10, r: 2.1–40, µ=21.3 ±11.8). Thorax with different length (n=9, r: 0.4–5, µ=3.4 ±1.5) and width (n=10, r: 0.2–3.1, µ=1.8 ±0.9). Variable number of abdominal chaetigers (n=6, r: 55–106, µ=69.3 ±19.2). In some specimens, radioles with 1–3 bands of brown iridescent pigment and opercular peduncle without pigmentation. Peduncle, including opercular plates, varying in length (n=10, r: 0.8–10, µ=5.6 ±3), inserted into right (n=6) or left lobe (n=4). Operculum variable in length (n=10, r: 0.2–4, µ=1.9 ±1.1) and number of plates (n=9, r: 3–8, µ=5 ±1). All opercular plates deeply dish-shaped. On the specimen used for this description (UMAR-Poly 835) the opercular plates are more widely separated than in other reviewed specimens ( Figs 3A–D , 5C–D ). All specimens with seven thoracic chaetigers. Collar with Spirobranchus - type chaetae with a narrow proximal boss (1.3:1 wider than distal blade) with many teeth; denticulate capillaries present as well ( Fig. 6D–F ).

Habitat. Littoral to sublittoral (64 m, Treadwell 1937). Below rocks, on live or dead coral ( Pocillopora verrucosa (Ellis & Solander, 1786) and P. damicornis ), oysters and pier piles ( Bastida-Zavala 2008). Occasionally part of fouling fauna ( Bastida-Zavala et al. 2016).

Distribution. Tropical Eastern Pacific, from the Gulf of California to Colombia ( Bastida-Zavala 2008).

Remarks. Mörch (1863: 399, pl. 11, Fig. 15) described the species from the Pacific of Costa Rica as Pomatostegus krØyeri ; however, here the spelling was corrected because the ICZN Art.32.5.2.1 explicitly states that an “o slash” (ø), as in Mörch’s original krØyeri , should be corrected to an “o” without slash. The type specimens are not in the Zoologisk Museum, Copenhagen, and are presumably lost.

The records of Pomatostegus stellatus from the Tropical Eastern Pacific region are questionable, as was mentioned in the previous species. In this work, we demonstrate that P. kroyeri differs from P. stellatus in the shape of the opercular plates and Spirobranchus - type chaetae: Pomatostegus kroyeri has deep dish-shaped opercular plates and the Spirobranchus - type chaetae have a narrow proximal boss, while P. stellatus has shallow dish-shaped plates and a wide proximal boss in the Spirobranchus - type chaetae.

Figures

FIGURE 3. Specimen of Pomatostegus kroyeri Mörch, 1863 from Puntarenas, Costa Rica.A. operculum with deep dish-shaped plates; B. radiolar crown with bands of black-blue iridescent pigment; C. opercular peduncle maculated; D. complete body, dorsal view.

FIGURE 4. Specimen of Pomatostegus kroyeri Mörch, 1863 from Puntarenas, Costa Rica.A. limbate chaeta; B. Apomatus-type chaeta; C. abdominal chaeta: flat narrow geniculate; D. thoracic uncinus; E. abdominal uncini.

FIGURE 5. Pomatostegus stellatus: Operculum with shallowly dish-shaped plates. A. specimen from Mahahual, Quintana Roo; B. specimen from Contoy Island, Quintana Roo. P. kroyeri: Operculum with deeply dish-shaped plates. C. specimen from Caleritas Beach, Baja California Sur; D. specimen from Caleta de Chón, Guerrero.

FIGURE 6. Variability of Spirobranchus-type chaetae. Pomatostegus stellatus: A–B. specimens from Cozumel, Quintana Roo; C. specimen from Contoy Island, Quintana Roo. P. kroyeri: D. specimen from Margarita Island, Magdalena Bay, Baja California Sur; E. specimen from Caleta de Chón, Guerrero; F. specimen from Camarón Beach, Oaxaca.

FIGURE 8. Tubes of species of Pomatostegus. A. Tube of P. stellatus, anterior view; B. Tube of P. kroyeri; C. Tube of P. actinoceras; D. Pomatostegus stellatus, in vivo, between a coral colony, from Chinchorro Bank, Mexican Caribbean (C. modified from Bailey-Brock et al. 2012; D. photo by Humberto Bahena, September 2000).

FIGURE 9. Distribution of Pomatostegus stellatus and P. kroyeri, including literature records (closed symbols) and specimens revised (open symbols).