Cerapus, Say, 1917

Just, Jean, 2017, A fresh look at the higher classification of the Siphonoecetini Just, 1983 (Crustacea, Amphipoda, Ischyroceridae) 12: with a key to all taxa, Zootaxa 4320 (2), pp. 321-338 : 326

Cerapus -clade, Lowry & Berents (1996)

Type genus. Cerapus Say, 1917

Diagnosis. Antenna 1 peduncle article 1 inflated; without accessory flagellum (vestigial in Runanga ). Antenna 2 slender compared to antenna 1 ( Fig. 2 B 1 ). Mandible palp with 3 articles, ( Fig. 2 B2 ). Gnathopod 1 propodus oval, as long as or longer than carpus ( Fig. 2 B 3 ). Gnathopod 2 male carpochelate or rarely subchelate ( Bathypoma ), carpus about as long as propodus ( Fig. 1 B 4 ). Coxae broader than long, margins entire. Pereonite 5 of mature females often elongate, coxa enlarged ( Fig. 2 B 5b). Pereopod 5 shorter and stouter than more slender 6 and 7, carpus surrounded by anterodistal and posterodistal projections. Pereopods 6 and 7 of equal shape, 7 the longer ( Fig. 2 B 5a); dactyli of 5–6 backward pointed, of 7 forward pointing. Urosomites 1–3 free. Uropod 1 with 2 rami, peduncle with ventrodistal corona. Uropods 2 and 3 with single, short ramus, 3 with apical denticles, ( Fig. 2 B 6). Telson more or less strongly cleft, each lobe with dorsal spine field.

Component genera: Bathypoma Lowry & Berents, 1996 ; Cerapus Say, 1817 ; Notopoma Lowry & Berents, 1996 ; Paracerapus Budnikova, 1989 ; Runanga Barnard, 1961 .

* The subfamily names Cerapinae Smith, 1880 and Cerapiinae Budnikova, 1989 both take Cerapus Say, 1817 as genotype. The names are incorrectly constructed. Smith’s name, which has priority, is here corrected to Cerapodinae Smith, 1880.

Figures

FIGURE 1. A. The relationship among the proposed tribes in the subfamily Ischyrocerinae based on clades identified by Lowry & Berents (1996). B. Subtribes in tribe Siphonoecetini as established here. (Illustrated: A, Cephaloecetes schioettei Just, 2017, in abode; B, Rhinoecetes coclearis Just, 2012 a, abode aggregation).

FIGURE 2. A, Ericthonini; B, Cerapodini; C, Siphonoecetini. 1, antennae; 2, mandibles; 3, gnathopod 1; 4, gnathopod 2 (c 1 simple and c 2 subchelate forms); 5 a, pereopods 5 – 7; 5 b, pereonite 5 with coxa; 6, telson with uropod 3. (A 2 from Lowry & Berents 1996; A 6 from Lowry & Berents 2005; B 2 from Krapp-Schickel 2013.)

FIGURE 3. A, coxal plate 2 (and 3); B, distal parts of pereopod 5 (and 6); C 1, Siphonoecetina urosome, C 2 and C 3, Bubocorophina urosomes, C 4, Caribboecetina urosome; D, sternal papillae on pereonite 7. E, antenna 2 flagellum, 1 – 3 articles 1 – 3; F, uropod 1, vv ventral view, lv lateral view, (refers to keys below).

FIGURE 4. A, lateral and dorsal views of heads of Rhinoecetes spp.; B, lateral view of head with pseudorostrum; C, complexly lobate lower lip; D, simple lower lip; E, pereopod 7; F, rami of uropod 1 of Rhinoecetes spp., G, uropod 3 with rounded ramus; H, natatory antenna 2 of Australoecetes sellicki.