Scyra Dana 1851

Genus Scyra Dana, 1851

Diagnosis (preliminary). CARAPACE teardrop-shaped, triangular in outline regions, feebly separated and elevated regions armed with blunt tubercles, surface smooth with microscopic, apically flattened setae, thickly covered with tomentum; supraorbital eave developed; pseudorostral spines relatively short, laminiform, deeply divided, covered with hooked setae; preocular tooth obtuse, postocular lobe markedly pointed and its inner surface slightly cupped; pterygostomial region with ridge bearing several tubercles; infraorbital lobe rudimental. ANTENNULA with basal segment not truncate, short, slender, armed with large distal tooth on outer margin. ANTENNA basal segment bearing terminal tooth and tubercle on outer border near base. CHELIPEDS similar in size and form, stouter than ambulatory legs in both sexes, covered with velvet-like tomentum; fingers occluding throughout their length. AMBULATORY PEREIOPODS generally unarmed, decreasing in length posteriorly, prismatic in cross-section. THORACIC STERNITES smooth, with shallow broad depressions. GONOPORES comma-shaped, nearly circular in lateral 2/3 and elongated in mesial 1/3. PLEON with 6 pleomeres and telson; pleomeres III–VI fixed, with distinct suture. GONOPOD shaft I straight, trilobate in distal part; hiatus between dorsal, mesial lobes wide; mesial, lateral margins from dorsal to ventral lobe clearly concave medially; lateral margin higher than mesial margin, dilated in median part. GONOPOD II shaft stout, slightly narrowed distally, truncated apically; apex with relatively large, triangular, subacute projection.

Remarks. Prior to the present study, the spider crab genus Scyra included S. acutifrons Dana, 1851 (the type species of the genus), known from the western coast of North America (Dana 1851), S. compressipes and S. tuberculata Yokoya, 1933, which are known from the northwestern Pacific, from the Sea of Japan and adjacent areas (Yokoya 1933; Marin et al. 2022). Pisoides bidentatus, Pisoides ortmanni, Pugettia quadridens and Pugettia ferox Ohtsuchi & Kawamura, 2019 are transferred to the genus herewith (see below).