Ophiuroglypha irrorata irrorata (Lyman, 1878)

Fig. 6G‒L

Ophioglypha irrorata Lyman, 1878: 73‒74, pl. 4, figs. 106‒108.

Ophioglypha orbiculata Lyman, 1878: 74‒75, pl. 4, figs. 103‒105.

Ophioglypha grandis Verrill, 1894: 293‒295 .

Ophioglypha tumulosa Lütken & Mortensen, 1899: 120‒122, pl. 1, figs. 9‒13.

Ophioglypha involuta Koehler, 1897: 295‒297, pl. 6, figs. 16‒18.

Ophioglypha figurata Koehler, 1908: 587‒588, pl. 9, figs. 83‒84.

Ophioglypha integra Koehler, 1908: 584‒585, pl. 8, figs. 79‒80.

Ophiura irrorata . H.L. Clark 1911: 62‒64; 1913: 209; 1917: 445‒446.— Koehler 1922: 380.— Tommasi 1976: 292, figs. 14‒17, 43‒48.— Martynov & Litvinova 2008: 79‒80, fig. 1c.

Ophiura (Ophiuroglypha) irrorata irrorata . Paterson 1985: 123‒124, figs. 46‒47.

Ophiuroglypha irrorata . Stöhr & O’Hara 2021: 518‒519, fig. 3c‒d.

See Paterson (1985) and Stöhr & O’Hara (2021) for other synonymous records.

Material examined. 12 individuals at three stations. TALUD XII, Sta. 8, 1 ind. (ICML-EMU-11144-B); Sta. 15, 1 ind. (ICML-EMU-13001); Sta. 25, 8 ind. (ICML-EMU-11144-A) and 2 ind. (ICML-EMU-11693).

Comparative material. Ophioglypha tumulosa Lu ̈tken & Mortensen, 1899, syntypes, 36 ind.: MCZ OPH-613, MCZ OPH-615, MCZ OPH-616, USNM 19451, USNM 19452, USNM 19454, USNM 19455, USNM 19456, USNM 19457, USNM 19458, USNM 19459, USNM 19461 (Supplementary file 2).

Description (ICML-EMU-11144-A). DD = 24 mm. Disc rounded. Dorsal disc covered by numerous irregular scales, smallest in the center, largest at disc margin.Central primary plate rounded, separated from the rest of semilunar primary plates. RS slightly broader than long, oval, separated from each other, one oval plate between each pair of RS (Fig. 6G). Ventral interradii covered by imbricated, irregular scales. Genital slits with papilliform genital papillae, projecting dorsally and forming discrete arm combs with oblong short papillae (Fig. 6H). OSh slightly broader than long, pentagonal, rounded distal edge. Madreporite not evident. AdSh longer than broad, elongated, slender, almost meeting or meeting in front of OSh. Jaws bearing 6‒7 papillae at each side; BSc rectangular, elongated; IPa similar in shape but larger than BSc; 2IPa 3‒4 quadrangular, slightly pointed; TPa two pointed, the apicalmost the largest. vT pointed, larger than oral papillae. Preceding ossicles separated by a diastema; one AdShSp, 8‒9 2AdShSp, elongated, rectangular with rounded edges (Fig. 6I). Arms gradually narrowing distally. First 2‒3 DAP broader than long, overlapping; subsequent DAP broader than long, trapezoidal, meeting (Fig. 6J). VAP broader than long, diamond-shaped, separating and decreasing in size distally. LAP with 3‒4 ArSp, minute (approximately 1/4 LAP in length), blunt, one longest and located dorsalmost and 2‒3 separated and located ventralmost. First tentacle pore with 8‒9 elongated, rectangular with rounded edges TSc, distalmost adradial scale enlarged; subsequent tentacle pores with fewer TSc until there is none distally (Fig. 6K). Color pattern beige-whitish (ethanol preservation) (Fig. 6G‒L).

Habitat and distribution. Atlantic (including the Caribbean), Pacific, and Indian Oceans; 403‒ 7,340 m depth (Paterson 1985; Martynov & Litvinova 2008). In the eastern tropical Pacific, it is distributed in Mexico, off Coco Island (Costa Rica), Panama, Colombia, Ecuador, the Galapagos Islands, and Peru; muddy and sandy bottoms (Lütken & Mortensen 1899; Solís-Marín et al. 2013). The material examined was collected off Colima and Guerrero; 1,858 ‒2,125 m depth.

Remarks. The examination of the type of Ophioglypha tumulosa and the TALUD material of this species indicated that some specimens can have only the central primary plate evident or all the primary plates very conspicuous. Further morphometric analysis is therefore required in order to elucidate if there is any pattern related to the size of individuals. Ophiuroglypa irrorata irrorata is distributed worldwide (Paterson 1985) and is one of the most predominant abyssal species (Martynov & Litvinova 2008). Moreover, it belongs to the group “ Ophiura irrorata ” proposed by Paterson (1985), which includes species and subspecies sharing the character of an enlarged distal tentacle scale on the proximal tentacle pores. Ophiura irrorata constitute a species complex with unclear morphological differences, which have been interpreted as intraspecific variability; according to recent studies, Indo-Pacific and Pacific oceans specimens concur with O. irrorata irrorata (Christodoulou et al. 2019; Stöhr & O’Hara 2021). Further morphometric and molecular analyses are needed to corroborate if the subspecies from the eastern Pacific are similar to the material from the rest of the world or not. Records off Colima and Guerrero are new for these areas and fill the distribution gap of this species in the Mexican Pacific.