Paracallianidea Sakai, 1992

Poore, Gary C. B., 2015, Rediagnosis of Callianideidae and its genera (Crustacea: Decapoda: Axiidea), and description of a new species of Heardaxius Sakai, 2011, Zootaxa 3995 (1), pp. 229-240 : 236-237

Paracallianidea Sakai, 1992

Paracallianidea Sakai, 1992: 17 .— Sakai 2011: 205 –206.

Type species. Callianidea laevicauda Gill, 1859 (original designation and monotypy).

Diagnosis. Gonochoristic. Rostrum obsolete. Linea thalassinica short. Thoracic sternite 7 with narrow anterior part, slightly separating cushion-like coxae of pereopods 4. Pleomere 1 tergite with strongly domed anterior part. Eyestalks flattened, contiguous, with truncate apex; weakly pigmented cornea dorsal. Antennal scaphocerite minute and articulating. Maxilliped 3 exopod reaching at least as far as end of ischium, with toothed crista dentata, ischium and merus without brush of stiff non-tapering setae. Pereopods 1 dissimilar, minor cheliped cylindriform. Pereopod 3 propodus about as long as broad, with distal spiniform seta. Pereopod 4 propodus with distal spiniform seta. Pereopod 5 subchelate. Setal-rows on anterolateral carapace, pleomeres 1 and 6. Male pleopod 1 present, of 1 or 2 weakly separated articles, distal article triangular, appendix interna represented by mesial row of hooks. Pleopod 2 of male with elongate appendix masculina with long terminal setae, and elongate appendix interna attached mesially. Pleopods 2–5 rami with simple segmented tubular marginal filaments. Uropodal endopod without transverse row of short spiniform setae; exopod ovate, without dorsal plate.

Included species. Paracallianidea laevicauda Gill, 1859 ; P. mariamartae ( Hernáez & Vargas, 2013) (probably a junior synonym of P. occidentalis ); P. occidentalis ( Schmitt, 1939) .

Remarks. Paracallianidea differs most significantly from Callianidea in the male pleopod 1, the appendix interna being reduced to a mesial row of hooks on the triangular article 2 (not thumb-like as in Callianidea ), and in the appendices on the male pleopod 2 (appendices interna and masculina separated, not fused). Pleopodal filaments are simple, as in C. madagascariensis but not branching as in C. typa ) so not as diagnostic as first thought. Of the other supposed differences the presence of a short linea thalassinica is trivial and the spine on the merus of maxilliped 3 is found in at least one species of Callianidea . Poore (1997) believed the two genera synonymous.

Paracallianidea occidentalis , erected as an eastern Pacific subspecies of the western Atlantic and Caribbean species, P. laevicauda , is now thought to deserve species rank (D.L. Felder, pers. comm.). Paracallianidea mariamartae , also from the eastern Pacific, resembles P. occidentalis in having a denticulate lower margin on the propodus of the cheliped, the very character said by Schmitt (1939) to differentiate his subspecies from P. laevicauda laevicauda ( Hernáez & Vargas 2013) . Paracallianidea mariamartae is therefore a probable junior synonym of P. occidentalis but a final conclusion awaits examination of type specimens or molecular data.