Heardaxius rogerbamberi, Poore, Gary C. B., 2015

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 : 233-235

Heardaxius rogerbamberi n. sp.

( Figs 1 a–f, 2, 3)

Material examined. Holotype. Papua New Guinea, Madang, Rempi Area, 05°01.6'S, 145°47.9'E, 2–15 m ( PAPUA NIUGINI stn PR81), MNHN IU- 2013-7093 (ovigerous hermaphrodite, cl. 4.2 mm).

Paratypes. Papua New Guinea, New Ireland, Nago I., off resort, 02°36.3'S, 150°46.2'E, 5.5 m ( PAPUA NIUGINI stn KR6), MNHN IU- 2014-1037 (2 non-ovigerous hermaphrodites, cl. 3.4, 4.0 mm); NMV J62083 (ovigerous female, cl. 3.7 mm).

Description. Carapace with broadly triangular rostrum; linea thalassinica lateral to eyes running 0.8 length of carapace; anterolateral setal row of about 12 setae; weak cervical groove present just posterior to midlength.

Pleomere 1 as long as pleomere 2, tergite with anterior part two-thirds width of posterior part, without anterolateral lobes, pleuron rounded ventrally, lateral setal-row with 6 setae on pleomere 1; pleomeres 3–6 of approximately same length, flattened; pleomere 6 with 2 transverse setal-rows, each of 8 setae. Telson 0.75 times as long as broad, lateral margin diverging over proximal half to obtuse angle, concave over distal lateral half; posterior margin evenly convex, evenly setose.

a c

d

e b

a-e, g, h, j, k, m

f

f l

g

i

k h m o

n

j Eyestalks flattened, contiguous, each with spine-like distal projection. Antennular peduncle length 1.7 times interlinea distance, with article 1 shorter than eyestalk, article 2 shorter than article 1, article 3 1.8 times article 2, with few setae on lower margin. Antennal peduncle twice as long as interlinea distance, with minute acute scaphocerite; article 5 0.7 times as long as article 4, reaching just beyond last antennular peduncle article.

Maxilliped 3 pediform, with exopod fifth length of ischium; basis with small spine; ischium with crista dentata of c. 14 spines, lower mesial face with field of additional spines and tubercles, lower margin setose; merus 0.6 times as long as ischium, with facial and lower rows of setae; carpus-dactylus unarmed, about as long as basismerus.

Pereopods 1 (chelipeds) subequal, similar; ischium with 8 small spines on lower margin; merus ovate with convex upper and lower margins, 1.5 times as long as wide; propodus with fixed finger about as long as upper margin of palm, with small tooth third way along cutting edge; dactylus slightly overreaching fixed finger, unarmed. Pereopod 2 propodus 1.6 times as long as wide, without setal-row. Pereopod 3 propodus with convex upper and lower margins, 1.5 times as long as wide, with distal spiniform seta. Pereopod 4 propodus 2.7 times as long as wide1, without distal spiniform seta. Pereopod 5 propodus 8 times as long as wide, not subchelate or chelate, with distal spiniform seta. Female gonopore open on coxa 3; male gonopore on coxa 5.

c d a b Gill formula as in H. salvati .

Pleopod 1 of 2 articles, geniculate. Pleopod 2 exopod shorter than endopod; endopodal appendices fused, appendix masculina with about 10 long distal setae, appendix interna extending, thumb-like beyond end of appendix masculina by 4 times its length. Pleopods 3–5 each with digitiform appendix interna.

Uropod reaching beyond telson; endopod ovate, 1.2 times as long as wide, with minute spine at end of anterior margin and 2 spines facially on longitudinal rib, with numerous short spiniform and long tapering marginal setae; exopod ovate but expanded anteriorly, 1.3 times as long as endopod, 1.3 times as long as wide, with numerous short spiniform setae and long tapering marginal setae.

Etymology. For Roger Bamber, good friend and fellow carcinologist, in appreciation of many hours spent in conversation over fine food and drink in Australia and the UK, and for his contribution to crustacean discovery and description.

Remarks. Heardaxius rogerbamberi differs from H. salvati in having a more pronounced discontinuity on the lateral margin of the telson, and the telson being shorter than wide rather than longer than wide. The anterior margin of the uropodal endopod is straighter than in H. salvati and terminates in a small spine not seen in the latter species; Ngoc-Ho (2005) illustrated a single spine on the face of the endopod whereas the new species has two.

Figures

FIGURE 1. Heardaxius rogerbamberi n. sp. Holotype. a, b, habitus in lateral and dorsal views. c, coxa of pereopods 2 – 4 and thoracic sternite 7 in ventral view (male and female gonopores arrowed). d, left cheliped. e, pleomere 6, telson and uropods. Dissected left maxilliped 3, mesial views. f, Heardaxius rogerbamberi, holotype. g, Thomassinia aimsae (MNHN IU- 2013 - 7082). h, i, Thomassinia gebioides, with detail of meral setae (FMNH UF 38171). j, Thomassinia moorea (FMNH UF 29264). Black scale bars = 1 mm; white scale bar (f, g, i,, j) = 0.1 mm).