Bartholomea annulata

Natural history. — Bartholomea annulata lives in shallow waters inside crevices of rocks and coral rubble, with only its tentacles above the substrate, in the lagoon and back-reef zones, often between 1 – 15 m but observed down to 20 m. Often observed in caves and crevices at the interface between hard and sandy substratum. Bartholomea annulata is commonly associated with the shrimp Ancylomenes pedersoni and the pistol shrimp Alpheus armatus Rathbun, 1901 (Manjarrés 1977; Ritson-Williams & Paul 2007). Alpheus armatus protects the anemone from predation by the fire-worm Hermodice carunculata (Pallas, 1766) and cleans the shelter, allowing the anemone to expand and retract its tentacles completely when disturbed; the anemone protects the shrimp from predation and provides it lodging (Smith 1977). Other crustaceans reported in association with B. annulata are Periclimenes yucatanicus, P. rathbunae, Thor amboinensis, Alpheus immaculatus Knowlton & Keller, 1983 and Alpheus polystictus Knowlton & Keller, 1985 (Manjarrés 1978, Knowlton & Keller 1983, 1985, 1986; Ritson-Williams & Paul 2007).

(Figure 10, Table 2)

Diagnosis. — Fully expanded tentacles and oral disc 100 – 150 mm in diameter. Oral disc 35 – 46 mm in diameter, smooth, flat, brownish, semi-transparent, with small white, yellow and green dots; sometimes base of first cycle of tentacles with triangular spots (Figure 10 B). Tentacles with distinct white spiral bands, more concentrated distally; epidermis in spiral bands thickened (Figure 10 A – C, F). Tentacles 48 – 96, hexamerously arranged in four to six cycles, inner ones longer than outer ones, long, slender, brown, semi-transparent (Figure 10 B – D). Column elongated, 12 – 45 mm in height, 15 – 38 mm in diameter, divided into capitulum and scapus (Figure 10 C). Capitulum smooth, light to dark brown, with white and yellow spots. Scapus smooth but corrugate in appearance when contracted. One or two rows of cinclides in mid-scapus. Pedal disc well developed, 8 – 24 mm in diameter (Figure 10 D). Pedal disc and scapus light brown or beige, semi-transparent, mesenterial insertions visible. Mesenteries hexamerously arranged in four cycles (48 pairs in specimens examined): first cycle perfect, others imperfect. No gametogenic tissue observed in specimens reviewed. Two pairs of directives each attached to a well developed siphonoglyph (Figure 10 E). Retractor muscles strong, restricted (Figure 10 E); parietobasilar poorly developed. Basilar muscles poorly developed. Marginal sphincter muscle not observed. Longitudinal muscles of tentacles ectodermal. Acontia white, with basitrichs and microbasic p - amastigophores. Zooxanthellae present. Cnidom: basitrichs, holotrichs, microbasic p- amastigophores and spirocysts (Figure 10 G – T; see Table 2).

Remarks. — Currently Bartholomea has three valid species, of which B. annulata and B. werneri Watzl, 1922 are reported for the Caribbean Sea (Fautin 2011). According to Watzl (1922), the spiral bands in the tentacles of B. werneri are more widely spaced than those in B. annulata. Further studies are needed to establish if the difference in the arrangement of the spiral bands of both species represents a species level difference or intraspecific variation.

Distribution. — From Bermuda to Barbados, along the entire Caribbean Sea (see Table 1). In the Mexican Caribbean, this species is reported in Cozumel and Puerto Morelos reefs (INE 2000; Sánchez-Rodríguez et al. 2001, 2006; Jordán-Dahlgren 2008), but this is the first time recorded for Majahual, Punta Cancún, Isla Mujeres, Akumal, Xcalak, and Isla Contoy reefs.

Material examined. — Puerto Morelos (20 ° 52 ’ 0.39 ” N, 86 ° 51 ’ 41.67 ” W; 5 specimens), Majahual (18 ° 42 ’ 28.18 ” N, 87 ° 42 ’ 36.92 ” W; 1 specimen); Punta Cancún (21 ° 9 ’ 10.5 ” N, 86 ° 44 ’ 41.2 ” W; 1 specimen); Isla Mujeres (21 ° 11 ’ 55.06 ” N, 86 ° 43 ’ 35.88 ” W; 2 specimens), Akumal (20 ° 23 ’ 39.68 ” N, 87 ° 18 ’ 47.39 ” W; 1 specimen); Xcalak (18 ° 15 ’ 53.55 ” N, 87 ° 49 ’ 43.20 ” W; 1 specimen); Isla Contoy (21 ° 28 ’ 16.98 ” N, 86 ° 47 ’ 27.87 ” W; 1 specimen).