Bathydorus spinosissimus Lendenfeld, 1915

Tabachnick, K. R., Menshenina, L. L. & Ehrlich, H., 2023, Rossellidae (Porifera: Hexactinellida) from the Bering Sea and off Bering Island, Invertebrate Zoology 20 (1), pp. 57-89 : 69

Bathydorus spinosissimus Lendenfeld, 1915

Fig. 10 ; Suppl. Tab. 9.

MATERIAL. IORAS 5/2/2084; IORAS 5/2/ 2223: RV ‘ Akademik Mstislav Keldysh’ – 22, sta. 2309, trawl, N off the Bering Island, 55°13.24– 12.02′ N 167°29.07 –26.7′ E, 3957–3978 m . MIMB: lv-82-5 sp2: RV ‘ Akademik M.A. Lavrentyev’ – 82, sta. 5, ROV ‘ Comanche’ , 55.2647° N 167.3013° E, 3879 – 3875 m .

DESCRIPTION. BODY. The specimen IORAS 5/2/2084 is one large fragment of the wall 50x 150 mm and several smaller fragments. The specimen IORAS 5/2/2223 is a small fragment likely of the same specimen. The walls are 1.5–2 mm thick, from atrial side the walls are relatively smooth, from dermal side they have some sparse and small outgrowths about 1 mm high and same in diameter.

REMARKS.Thespecieswasoriginallydescribed as a subspecies Bathydorus laevis spinosissimus Lendenfeld, 1915 . Here it is considered as a separate species. Some differences between the holotype and the newly collected specimen are considered as an interspecific variation. Dermal and atrial spicules are very similar in shape. They have rays with dense covering of spines; atrial hexactins have a ray direct- ed outside the body pinnular. Dermal spicules and microscleres are generally smaller in the newly found specimen. But in both specimens from distantly located areas, from the Bering Sea and off the N Peru, dermalia are generally stauractins and pentactins, and all transitional forms from diactins to hexactins may be rarely found. Both of them often have rudimental tubercles or short rays instead of those (distal and proximal) not completely developed. The new specimens have some rare dermal and atrial spicules with branching rays and some rare oxyoidal microscleres of abnormal forms with reduced number of primary and secondary rays and some of the rays notably curved. Some oxyhexasters in the new specimen have notable amount of secondary rays – up to 6, some rare oxyhexactins were observed there as well .

DISTRIBUTION. Pacific Ocean : off N Peru and N off the Bering Island, at 3957–4063 m depth .

Figures

Fig. 10. Spicules of Bathydorus spinosissimus, IORAS 5/2/2084. A–C — dermal stauractins. C — dermal stauractin with branching rays. D — dermal pentactin. E — dermal hexactin. F — atrial pinular hexactin. G–H — oxyhexasters. I — oxyhemihexaster. J–K — abnormal oxyoidal microscleres. L — oxyhexactin. Рис. 10. Спикулы Bathydorus spinosissimus, IORAS 5/2/2084. A–C — дермальные стаурактины. C — дермальнаЯ стаурактина с ветвЯЩимисЯ лучами. D — дермальнаЯ пентактина. E — дермальнаЯ гексактина. F — атриальнаЯ пинулЯрнаЯ гексактина. G–H — оксигексастры. I — оксигемигексастр. J–K — анормальные оксиоидные микросклеры. L — оксигексактина.