A new species and two new genera of pinnotherid crabs from the northeastern Pacific Ocean, with a reappraisal of the subfamily Pinnotherinae de Haan, 1833 (Crustacea: Brachyura: Pinnotheridae)

Abstract

Two monotypic genera, Enigmatheres new genus, and Bonita new genus, are described to receive Fabia canfieldi Rathbun, 1918, and Bonita mexicana new species respectively. Enigmatheres can be distinguished from other Pinnotheridae by the third maxilliped having a gently curved outer margin, with a carpus that is larger than the conical propodus and a dactylus that is inserted on the middle third of the ventral margin of the propodus, walking legs 2 that are asymmetrical in length and the dactyli of walking legs 1, 3 and 4 that are short, slender, conical, slightly curved up to hooked and hard tip. Bonita can be distinguished from other Pinnotheridae by the presence of two sulci on the carapace, protruding anterolateral margins of the carapace, walking leg 3 asymmetrical in length and larger than other walking legs, and walking leg 4 with a clavate propodus. These two new genera and 25 additional ones (nine with hesitation), including Pinnotheres Bosc, 1802 (type genus of Pinnotherinae de Haan, 1833), share a carapace that is soft and thin, walking legs 1-4 that are slender and feeble, antennae with a protuberance on the basal segment and the known zoea larvae being very similar, particularly with an abdomen that widens from somite 1 to 5 and a telson that is laterally convex and posteriorly trilobed. These adult and larval shared features support the monophyly of these genera and clearly diagnose the subfamily Pinnotherinae de Haan, 1833 sensu stricto.