Ensiger Borradaile, 1915

de Gier, Werner & Fransen, Charles H. J. M., 2023, Polka-dotted treasures: Revising a clade of ascidian- and bivalve-associated shrimps (Caridea: Palaemonidae), Contributions to Zoology 92 (3), pp. 179-282 : 219

Genus Ensiger Borradaile, 1915

ZooBank: urn:lsid:zoobank.org:act:012A13F1-C8A9-4C9F-B4E7-E8B5EE345560

Ensiger Borradaile, 1915: 207 . Type species, being the first species subsequently placed in this subgenus, which was described without any nominal species: Anchistia aurantiaca Dana, 1852 (a junior subjective synonym of Cancer custos (Forskål, 1775) ; first placed in Ensiger by Borradaile, 1917.The genus is herein resurrected. Gender: masculine. Etymology: Borradaile (1915, 1917) did not provide information on the derivation of the name. From ensiger (Latin) = sword-bearer; probably in reference of the sword-like rostrum of the type-species.

Both the type species, Anchistus custoides Bruce, 1977 , and Anchistus custos (Forskål, 1775) are herein transferred to Ensiger Borradaile, 1915 .

Diagnosis. Moderately sized shrimps of subcylindrical body form. Rostrum well developed, compressed, without teeth or with very shallow indistinct dorsal teeth, lateral carinae feebly developed. Carapace smooth, glabrous; orbit feebly developed, inferior orbital angle distinct, antennal spine present, supraorbital, hepatic and epigastric spines absent, antero-lateral margin somewhat produced, rounded. Abdomen smooth, glabrous, third segment not posterodorsally produced, anterior pleura rounded, posterior blunt. Telson with two pairs of small dorsal spines, three pairs of posterior spines. Eye small, cornea globular. Antennula normal, with basal peduncular segment with distolateral tooth, upper flagellum biramous, short ramus reduced. Antenna with basicerite unarmed, scaphocerite well developed, with moderately developed distolateral tooth. Epistome unarmed. Mandible normal, without palp, molar process robust, incisor process dentate; maxillula with feebly bilobed palp, laciniae broad; maxilla with simple palp, basal endite broad, bilobed, coxal endite obsolete, scaphognathite broad; first maxilliped with slender palp, basal endite broad, fused with coxal endite, exopod well developed, caridean lobe broad, flagellum with numerous plumose setae distally, epipod subrectangular, without podobranch; third maxilliped, ischiomerus and basis fused broad, exopod with numerous plumose setae distally, coxa with oval lateral plate, with or without rudimentary arthrobranch. Fourth thoracic sternite without median process. First pereiopods slen- der, chelae cannulate or sub-cannulate, with fingers subspatulate, cutting edges minutely pectinate. Second pereiopods well developed, similar, unequal, dactylus with large acute triangular tooth in proximal half, fixed finger with series of teeth in proximal part; propodus without tympanal organ. Ambulatory pereiopods with simple dactyli, without basal protuberance; unguis simple, without dorsal pad of fine scale-like spinules. Uropod with protopodite posterolaterally acute, exopod with small mobile distolateral spine.