Euginoma vermiformis Jullien, 1882

Souto, Javier, Reverter-Gil, Oscar & Fernández-Pulpeiro, Eugenio, 2011, Redescription of some bryozoan species originally described by J. Jullien from Iberian waters, Zootaxa 2827, pp. 31-53 : 43-45

Euginoma vermiformis Jullien, 1882

( Figs 29–36 ; Table 6)

Euginoma vermiformis Jullien, 1882: 520 , pl. 17, figs 58–59; Calvet 1907: 402, pl. 27, fig. 3; Prenant & Bobin 1966: 387, fig. 126; Hayward 1978b: 98 –103, figs 1–5.

Material examined. Lectotype (designated here): MNHN 100, Travailleur 1881, Dr. 41 (2nd ser.), 44°02’15’’ N, 9°27’30’’ W, 1094 m, ‘ Type du genre’, figured. Other material examined: MNHN 101, Travailleur, Dr. 49, 29º N, 18º28’ W, 3700 m; MNHN 2528, Travailleur, Dr. 1, 43°00’40’’ N, 11°57’40’’ W, 2018 m (labelled as Jubella enucleata ); MNHN 8323 (part), Thalassa , X362, 44º06.5’ N, 4º50.9’ W, 585–600 m; MNHN 8325 (part), Thalassa , X349, 44º07.1’ N, 4º43.8’ W, 570–615 m; MNHN 8363 (part), Thalassa , X353, 44º06.8’ N, 4º45.1’ W, 635–655 m; MNHN 8387 (part), Thalassa , X352, 44º06.5’ N, 4º45.2’ W, 545–580 m; MNHN 8392 (part), Thalass a, X348, 44º07.5’ N, 4º43.6’ W, 600–900 m; MNHN 8415 (part), Thalassa , Y 405, 40º33.1’ N, 9º26.5’ W, 1170 m; MNHN 8418, Thalassa , X305, 44º05.0’ N, 5º00.6’ W, 463 m; MNHN 8432, Thalassa , X347, 44º07.3’ N, 4º44.0’ W, 640– 910 m; MNHN 14925 (part), Balgim, DW107, 36º05.0’ N, 8º05.6’ W, 1909–1926 m; MNHN 15487 (part), Balgim, DW07, 36º46.1’ N, 9º27.0’ W, 1139–1144 m; MNHN 15493 (part), Balgim, DW11, 36º44.2’ N, 9º31.4’ W, 1505– 1540 m; MNHN 19806 (part), Balgim, DR06, 1112–1114 m.

Description. Colony erect, well calcified, forming long cylindrical branch about 0.45 mm diameter, slightly flattened dorsally; anchored to substratum by rhizoids. Branch unjointed, formed by four longitudinal series of alternating autozooids. Frontal side occupying about two thirds of circumference, remainder occupied by dorsal side; this divided into trapezoidal areas corresponding to the dorsal walls of two autozooids.

Autozooids arranged in pairs, not in contact within same series; frontal surfaces nearly perpendicular to each other; each pair rotated about 45º alternatively to left or right relative to proximal pair, hence alternate pairs placed in same position. Each autozooid arising as tubular rudiment from distal wall of preceding autozooid in same plane, traversing basal walls of next pair of autozooids. Branch slightly curved proximally, dorsal surface convex, frontal concave; distally colony almost straight. Autozooids rounded-hexagonal, convex, separated by fine, slightly raised sutures. Lateral and distal walls delimited by continuous semi-elliptical suture; proximally limited by two preceding autozooids so its medioproximal extreme is acute. Junction between lateral and frontal surfaces forming raised rim, with elliptical outline, most pronounced distally; rim less developed and even absent proximally. Frontal wall within rim concave, slightly raised in distal half, forming straight proximal border of orifice. Opesia approximately as wide as long, occupying distal third of depressed frontal area. Borders smooth, raised and slightly flared; lateral borders straight, continuing with largely convex distal border. No spines. Whole surface of colony covered by characteristic papillate surface.

Ovicell scarcely prominent, visible by elevation of proximolateral walls of two succeeding autozooids; suture between this pair dividing ovicell into two halves. Orifice of ovicelled autozooid enlarged, somewhat trapezoidal. Ovicellar orifice forming narrow half moon distal to autozoecial orifice. Ovicelled zooid occasionally with two large distolateral oval pores, later covered by secondary calcification. No avicularia or other heterozooids. Some basal autozooids with calcified arch over distal half, distal edge continuous with lateral borders of zoecial orifice, proximally opened. Ancestrula placed laterally in proximal extreme of branch; similar to later autozooids though smaller, proximal end tapering.

Mean SD Minimum Maximum N Autozooid length 0,507 0,0 512 0,442 0,594 10 Autozooid width 0,289 0,0 207 0,261 0,319 10 Opesia length 0,109 0,0 0 79 0,101 0,116 10 Opesia width 0,111 0,0 0 59 0,101 0,116 10

SD, Standard deviation; N, number of measurements.

Remarks. Euginoma vermiformis was originally described from material collected at 2018 m depth on Galicia Bank and at 1094 m northwest of the Iberian Peninsula. Calvet (1907), unusually did not reflect its first location, but reported a small colony from 3700 m at the Canaries. From Jullien’s original material, two samples are preserved. MNHN 100 is labelled as “ type du genre”, here designated as lectotype; MNHN 2528, also Jullien’s original, was labelled as Jubella enucleata but it also contains E. vermiformis (see Reverter-Gil & Fernández-Pulpeiro 2001) and it may correspond to the original material from dredge # 1 of the Travailleur but we cannot be sure. MNHN 101 from the Canary Islands is also preserved.

Hayward (1978b) redescribed the species from material collected by the Challenger in northwestern Bay of Biscay but did not examine Jullien’s specimens. While studying this original material, we have detected several minor differences from the descriptions made by Jullien (1882) and Hayward (1978b). In his original description, Jullien (1882) interpreted the median depression in the autozooids as a cryptocyst, while the whole zoecial wall is actually cryptocystal as demonstrated by Hayward (1978b).

Julien (1882) described the ovicell of E. vermiformis without including a figure; this mistake was later rectified by Calvet (1907, pl. 27, fig. 3). The original description indicates that the zooidal orificial rim is even in the ovicellate autozooids, opposed to the sterile autozooids, where it is granular. We have seen that this is not the rule, but varies according to the degree of calcification ( Figs 32 , 34–36 ). On the other hand, Hayward (1978b) found only three ovicells in his specimens, describing them as asymmetrical, as the suture between the pair of succeeding zooids was laterally displaced. In the material we have studied, the suture is always medial, as indicated in the original description of the species. In addition, we detected the existence of a pair of distolateral pores, not noted previously, in some ovicellate zooids in colonies collected by the Thalassa and Balgim ( Fig. 34 ). As calcification proceeds, the pores are covered ( Figs 35, 36 ).

In the revised material, nothing similar to the secondary branches described by Hayward (1978b) was found and they seem to be very rare. However, we observed zooids bearing rhizoids in the basal part of the colony ( Fig. 33 ) as noted by previous authors.

Euginoma vermiformis has been reported from the Bay of Biscay ( Hayward 1978b), the whole Atlantic coast of the Iberian Peninsula ( Jullien 1882; Hayward 1979; Harmelin & d’Hondt 1992) and the Canary Islands ( Calvet 1907; Harmelin 1977). Several taxa in the genus Euginoma have subsequently been described, especially by d’Hondt (1981) and d’Hondt & Schopf (1984); the latter included identification keys.

Euginoma vermiformis was also reported by d’Hondt (1975) from Azores Islands, but the included figure (d’Hondt 1975, fig. 25) reveals the material does not correspond to Euginoma . On the other hand, the left-hand branch illustrated by Hayward (1978b, fig. 1) exhibits autozooids in opposing pairs rotated about 90º, so a basal face of the colony, seen in E. vermiformis s.s., is not defined. This material, therefore, might correspond to a different species.

Figures

FIGURES 29 – 33. Euginoma vermiformis Jullien, 1882 (MNHN 100, lectotype). 29, A young colony; 30, dorsal side of a branch; 31, tip of a branch showing the rudiments of four autozooids; 32, ovicell; 33, proximal extremity of a branch with a rhizoid-bearing autozooid.

FIGURES 34 – 36. Euginoma vermiformis Jullien, 1882. 34, Ovicelled zooid with two distolateral pores and even rim (MNHN 15493); 35, ovicelled zooid with pores nearly closed by calcification (MNHN 8387); 36, ovicelled zooid without pores (MNHN 15487).