Mycale jasoniae Lehnert, Stone & Heimler, 2006, sp. nov.

Mycale jasoniae sp. nov.

(Fig. 14 a–f)

Material

Holotype: USNM 1084238 (51° 19.808' N, 179° 30.658' W, Amchitka Pass, 208 m depth, 0 3. 0 8. 2004).

Description

The holotype consists of two large and one small, yellow colored tubes (Fig. 14 a), basally connected. The surface is bulbous and the consistency rather soft, easily torn, fibrous. After freezing the specimen is now (Fig. 14 b), about 23 x 16 x 14 cm with irregularly distributed, conical processes. The color now is a darker yellow, with darker and lighter areas, some almost white. The specimen was attached to a cobble at the base.

Skeleton: The ectosome is a tangential arrangement of short spicule tracts and single spicules with many microscleres in between.The choanosome consists of rather short spicule tracts, 60–95 µm in diameter which are frequently branching off side tracts and are running in all directions. This pattern is obscured by many single mega­ and microscleres in between without any recognizable orientation.

Spicules: Megascleres are tylostyles (Fig. 14 c), 405–460 x 10–12 µm. Microscleres are anisochelae I (Figs. 14 d, e), 80–100 µm, anisochelae II (Fig. 14 f), 40–60 µm, rhaphides (Fig. 14 f), 42–65 µm.

Discussion

With its “mycalostyles”, two size categories of anisochelae and rhaphids this species has the characteristic spiculation of the genus Mycale. There are 17 species of Mycale known to occur in the area. M. jasoniae differs from all of them in the combination of two size categories of anisochelae with rhaphids. M. loveni (Fristedt, 1887) with its spicule set of tylostyles and two size categories of anisochelae is the most similar species. It differs from M. jasoniae in its stalked, funnel shaped growth, in lacking the rhaphids, in having tylostyles (350–509 x 13–16 µm) and large anisochelae (72–111 µm) of a larger size range and the small category of anisochelae (31–54 µm) is smaller. All other sympatric species of Mycale have sigmas among the microscleres or only one or three categories of anisochelae or have an additional category of microsclere. For a detailed comparison of all species of Mycale of the area with all spicule measurements included we refer to Lehnert, Stone & Heimler (2006: 20, table 4).

Distribution

Known only from the type locality.