Myxilla rosacea var. japonica Ridley & Dendy 1887

• Main Author: Van Soest, Rob W. M.
• Format: Other/Unknown Material
• Language: unknown
• Published: Zenodo 2024
• Subjects: Biodiversity; Taxonomy; Animalia; Porifera; Demospongiae; Poecilosclerida; Myxillidae; Myxilla; Myxilla rosacea; Myxilla rosacea var. japonica ridley & dendy; 1887; North Atlantic
• Online Access: https://doi.org/10.5281/zenodo.10568040; http://treatment.plazi.org/id/BF4E397FFFA031149786FF4FBFDA04B2

Myxilla rosacea var. japonica Ridley & Dendy, 1887 (Fig. 7J–K) Myxilla rosacea var. japonica Ridley & Dendy, 1887: 130, pl. XXVI fig. 3, XXVII fig. 8, XLVII fig. 3; Hoshino 1987: 34; Ise 2017: 373 (listed only) Dendoryx rosacea var. japonica Lindgren 1897: 482; 1898: 307, pl. 18 fig. 5. The variety was erected by Ridley & Dendy from Kobe, Japan, 34.62°N 135.23°E, depth 15–92 m (syntypes (fragments) BMNH 1887.5.2.111). It differs from the typical variety described by Lieberķhn (1859: 520, as Halichondria , from Triest, Northern Adriatic, approximate coordinates 45.683°N 13.6°E, neotype LMJG 15293, cf. Van Soest 2002c: 611) in the more densely spined choanosomal acanthostyles and the hastate condition of the ectosomal tornotes, which differs from the tridentate endings in the typical variety. Anchorate isochelae were cited in one size, whereas the typical variety has two size categories (12–15 and 20–25 µm), but Ridley & Dendy may have ignored the categories as they state the chelae are ‘up to about 30 µm’ covering the size of the two categories of the typical variety. Sigmata are slightly larger (up to 45 µm, only 17–35 µm in the typical variety). The tornote endings are a sure sign that the present variety is not a member of the North Atlantic Myxilla (Myxilla) rosacea , and accordingly I propose to recognize Myxilla (Myxilla) japonica (Ridley & Dendy, 1887) as a distinct species. Lindgren (1897, 1898) reported this variety (as Dendoryx ) from Strait Hirundo (=Hirado), Japan, 33.0833°N 129.2667°E. His description is meagre. Hoshino (1977: 7; 1981a: 140) described Japanese specimens of a ‘cosmopolitan’ Myxilla rosacea (Lieberķhn, 1859) without illustration. In Hoshino (1981a), he only listed the name, but synonymized the present variety with his M. rosacea . I suspect that his material likely belongs to an additional Japanese Myxilla species, as the descriptions and sizes of the spicules differ substantially from both North Atlantic Myxilla rosacea and the present variety. Published as ...