Michalisquilla, Ahyong, 2017

Michalisquilla n. gen.

Diagnosis. Dorsal integument finely pitted. Eye large, cornea bilobed. Ophthalmic somite anterior margin emarginate. Ocular scales separate. Carapace with anterolateral spines; median, intermediate, lateral, marginal and reflected marginal carinae present; median carina lacking branches of anterior bifurcation; lower posterolateral margin without obtuse angle. Mandibular palp absent or 1–3 articulate. Maxillipeds 1–5 each with epipod. Raptorial claw dactylus with 6 teeth; carpus with undivided dorsal carina; propodus unarmed distally; merus lacking outer inferodistal spine. Thoracic somite 5 lateral process a blunt diagonal projection, with small ventral spine. Thoracic somites 6–7 lateral processes triangular, faintly bilobed; anterior lobe considerably smaller than posterior lobe. Hook process of petasma apically blunt, longer than tube process. Abdominal somites 1–5 with distinct submedian, intermediate, lateral and marginal carinae; somite 6 with submedian, intermediate and lateral carinae. Telson with prelateral lobe; mid-dorsal surface with curved rows of pits; submedian teeth with fixed apices; postanal carina absent. Uropodal protopod with one lobe between terminal spines; inner margin crenulate.

Type species. Squilla parva Bigelow, 1891 , by present designation and monotypy.

Etymology. Derived from the combination of the Greek for Michael (MΙΧάλης) and the generic name Squilla , in honour of the late Michael Türkay for his career long contributions to carcinology. Gender feminine.

Remarks. Ahyong (2005) showed S. parva to lie outside of Squilla sensu stricto, being probably more closely related to Gibbesia Manning and Heard, 1997 . The presence of six rather than five teeth on the dactylus of the raptorial claw, the short and blunt rather than strongly produced lateral process of thoracic somite 5, and the blunt rather than spinular apex of the hook process of the male petasma, however, exclude S. parva from Gibbesia , justifying its removal to the new genus Michalisquilla . Michalisquilla parva n. comb. shares with species of Squilla a distinctly bilobed cornea, a unilobate lateral process of thoracic somite 5 and fixed submedian teeth on the telson. Michalisquilla , however, differs from Squilla as now restricted, in having the posterior lobe of the lateral process of thoracic somite 5 produced to a short, diagonal projection instead of a prominent lateral or anterolaterally produced spine, and a rounded instead of angular posterolateral margin of the carapace. Additionally, the hook process of the petasma is blunt in Michalisquilla instead of being produced to an apical spine, and the hook process of the petasma is markedly longer than, instead of about as long the tube process. Furthermore, Michalisquilla is the only squilloid in the Atlanto-East Pacific with variable segmentation of the mandibular palp, which may be absent or composed of 1–3 articles in adults.All species of Squilla , as well as all other Atlantic squilloids bear an apical spine on the hook process of the petasma, and lack variation in the condition of the mandibular palp. Crenatosquilla oculinova ( Glassell, 1942) is the only other eastern Pacific squillid with an apically blunt process on the petasma, but it differs in numerous diagnostic features and is phylogenetically distant, as a member of the Meiosquilla Group, rather than Squilla Group ( Ahyong, 2005).

Although further revision of Squilla is required, the removal of S. parva to Michalisquilla renders Squilla homogeneous for the major diagnostic features of a distally pointed hook process of the endopod of male pleopod 1, presence of a 3-articulate mandibular palp, and the lateral process of thoracic somite 5 as a single prominent anterolaterally produced spine.