Keroeides koreni Wright & Studer, 1889

Keroeides koreni Wright & Studer, 1889: 169–170, pl. 11, fig. 3 (Hyalonema ground, Japan).

Opinion: There is not enough evidence that this species occurs in the region.

Justification:

These Indian records seem to be either invalid or unconfirmable: Thomson & Henderson 1906: 22, pl. 1, fig. 6&7 (Andamans); Thomson & Simpson 1909: 167–168 (Lakshadweep); Fernando 2011: 26–27, pl. 7, fig. 2–2d (SE coast); Fernando et al. 2017: 44, pl. 16, fig. 2–2d (SE coast).

Literature analysis: As the holotype has never been redescribed, distributional records must all be based on the original description of Wright & Studer (1889), which, unfortunately, lacked a lot of detail. Originally found in over 600 m of water off Japan, it is unlikely that any of the shallow records from the region, such as those of Thomson & Simpson (1909), could be correct. Thomson & Henderson (1906) reported the species from nearly 500 m from the Andamans but gave no details about the sclerites. They did illustrate some relatively tall, conical calyces, but those of the holotype were described as being “somewhat flattened” and “little elevated”. They were also described as being 3–5 mm wide, which is unusually large and could be a misprint for 0.3–0.5 mm. The calyces in Bayer’s (1949) samples were 1 mm tall x 1mm across, and in Bayer (1956) they were 1 mm tall x 0.5–0.75 mm across, but there is no evidence that Bayer had examined the holotype.

The descriptions by Fernando (2011) and Fernando et al. (2017) are identical and they recorded Indian samples from 40–200m (which clearly includes shallow water). Fernando (2011) and Fernando et al. (2017) mistakenly stated that Grasshoff (1999) recorded K. koreni from New Caledonia, when in fact he only recorded K. gracilis from that region saying he considered K. koreni as a separate deep-water species. These Indian authors’ descriptions recorded the coenenchyme as containing polygonal and elongate plates whereas they illustrated spindle-shaped sclerites: the latter, however, actually conform better to the original description of the species. Their material is also described as having axial sclerites 0.8 mm long, which is twice the length of those in the holotype. The Indian authors reported the Y-shaped tentacle sclerite as being 0.7–0.9 mm long, and Bayer (1956) recorded them as 0.07–0.1 mm, but in the holotype the sclerites of the tentacles were stated to be 0.08–0.2 mm long. The holotype must be redescribed before any subsequent records can be validated. Venkataraman et al. (2004) just lists the species (as Keroeides koreni).