Thysanote Krøyer, 1863

Helna, Ameri Kottarathil, Aneesh, Panakkool Thamban, Ismail, Norshida & Maran, Balu Alagar Venmathi, 2025, Complementary description and further record of Thysanote rastrelligeri Rangnekar, 1962 (Copepoda: Siphonostomatoida: Lernaeopodidae) from a new host, Zootaxa 5642 (1), pp. 16-28 : 17-18

Genus Thysanote Krøyer, 1863

Type species. Thysanote pomacanthi Krøyer, 1863 (type by original designation)

Remarks. The species of Thysanote can be recognised by the following combinations of characters: short cephalothorax, usually in line with the trunk; indistinct carapace; large trunk, dorso-ventrally flattened and broadening backwards; uropods present, often prominent.; branched or unbranched processes at hind end of trunk, postero-median pair unbranched; antennule four segmented; antenna biramous, endopod two-segmented; mandible with oblique row of teeth; maxillule stout, palp small; maxillae short, free, with or without processes; prehensile maxillipeds (see Kabata and Tareen 1981; Pillai, 1985). The genus currently includes 20 valid species globally and the latest addition is description of Thysanote chalermwati Piasecki, Ohtsuka and Yoshizaki, 2008 , from Thailand ( Piasecki et al. 2008).

Status of Type Materials and Considerations for Neotype Designation of Thysanote rastrelligeri Rangnekar, 1962 : The original description of Thysanote rastrelligeri , included six figures depicting a nonovigerous female. Although the description contained species-specific details, it requires revision to meet modern taxonomic standards.

The type locality, i.e., the Mumbai coast, Maharashtra, India ( Fig. 7 ), was clearly stated in Rangnekar’s (1962) description, along with its type host, the Indian mackerel Rastrelliger kanagurta (Cuvier, 1816) and its site of attachment in the branchial cavity. However, Rangnekar (1962) did not provide information on the deposition or registration of type materials. Subsequent mentions of T. rastrelligeri by Pillai (1967, 1985) were based solely on the original description, and no additional records of this species have been reported.

Our inquiries at various repositories, including the Indian Museum, did not yield any specimens that could be identified as type materials of T. rastrelligeri . It appears that the original type specimens were either never deposited or are no longer available. Currently, the specimens examined herein (ZSI/WGRC/IR/INV/28933, ZSI/ WGRC/IR/INV/28934, ZSI/WGRC/IR/INV/28935), deposited at the Western Ghats Field Research Centre of the Zoological Survey of India (ZSI/WGRC), Kozhikode, are the only known materials that can be reliably identified as T. rastrelligeri .

The newly collected specimens described here were obtained from the Neendakara coast, Kollam, Kerala, India —approximately 1,000 km from the original type locality at Mumbai.According to ICZN Article 75.3.6 (Anon, 1999), a neotype should be designated from a locality that is "as nearly as practicable" to the original type locality. However, the newly collected T. rastrelligeri specimens were found on a different host species, Megalaspis cordyla , and from a different site of attachment. As these do not fully meet the ICZN criteria (Article 75.3) for neotype designation, we are preserving these three new specimens as voucher materials for T. rastrelligeri .

The present Indian specimens closely align with Rangnekar’s (1962) original description and illustrations, thus confirming that they belong to the same species.

Figures

FIGURE 7. Map of the distribution of Thysanote rastrelligeri Rangnekar, 1962 (1) Mumbai coast (the type locality), (2), Neendakara coast (new locality) (source: https://www.google.co.in/ maps).