Pomatostegus, Schmarda, 1861

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 : 496

Key to Pomatostegus species from the World

1 Operculum with shallow dish-shaped plates, almost flat, successive plates widely separated ( Figs 1A–D , 5A–B , 7A–C ); Spirobranchus - type chaetae with wide proximal boss, as wide as or wider than distal blade ( Figs 2A , 6A–C , 7D ); tube semi-circular ( Fig. 8A ) or triangular in cross-section ( Fig. 8C )............................................................ 2

– Operculum with deep dish-shaped plates, as a bowl, successive plates barely separated ( Figs 3A–D , 5C–D ); Spirobranchus - type chaetae with narrow proximal boss, narrower than distal blade ( Fig. 6D–F ); tube semi-circular in cross-section ( Fig. 8B )................................................................................. P. kroyeri Mörch, 1863

2(1) Distal tip of the column with one circlet of spines without accompanying plates; tube semi-circular in cross-section ( Fig. 8A )............................................................................ P. stellatus ( Abildgaard, 1789)

– Distal tip of the column with 2–4 circlets of spines without accompanying plates; tube triangular in cross-section ( Fig. 8C )................................................................................ P. actinoceras Mörch, 1863

Figures

FIGURE 1. Specimen of Pomatostegus stellatus (Abildgaard, 1789) from Contoy Island, Mexican Caribbean. A. operculum with shallow dish-shaped plates, lateral view; B. opercular peduncle maculated with brown pigment; C. peduncle with wide wings with the wavy edge; D. radiolar crown with bands of brown iridescent pigment.

FIGURE 2. Specimen of Pomatostegus stellatus (Abildgaard, 1789) from Contoy Island, Mexican Caribbean. A. Spirobranchus-type chaeta with a wide proximal boss; B. limbate chaeta; C. Apomatus-type chaeta; D. abdominal chaetae: flat narrow geniculate; E. thoracic uncinus; F. abdominal uncinus.

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 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 7. Pomatostegus actinoceras Mörch, 1863. A–C. operculum with shallowly dish-shaped plates, distal tip of the column with two “free” circlets of spines without accompanying plates; D. Spirobranchus-type chaetae with a wide proximal boss; E. thoracic capillary chaeta; F. Apomatus-type chaeta; G. abdominal chaeta: flat narrow geniculate; H. thoracic uncinus; I. abdominal uncinus. (A–I. modified after Bailey-Brock et al. 2012).

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).