Brucerolis howensis, Storey & Poore, 2009

Storey, Melissa J. & Poore, Gary C. B., 2009, New species of Brucerolis (Crustacea: Isopoda: Serolidae) from seas around New Zealand and Australia, Memoirs of Museum Victoria 66 (1), pp. 147-173 : 154-158

Brucerolis howensis sp. nov.

Figures 1d , 6 − 9

Material examined. Holotype: Tasman Sea, Lord Howe Rise , 34°59.3'S, 162°11.28'E, 1573 m, 26 Sep 1982 ( NIWA stn U198 SEB), NIWA 27431 (adult male, 29 mm).

Paratypes: collected with holotype, NIWA 27428 (adult female, 27 mm) , NIWA 27428 (adult male, 29 mm) , NIWA 27427 (2 males, 7 juveniles), NMV J55315 (1 male, 1 female); Tasman Sea, Lord Howe Rise , 31°34.0'S, 159°26.5'E, 1828 − 1808 m, 08 May 1979 ( NIWA stn I722), NIWA 27428 (1 male, 1 female) .

Other material: Tasman Sea , S of Lord Howe Plateau, 37°00'S, 170°00'E, 2096 m, 18 Apr 1970 ( NZ 0I stn J39), NIWA (1 female) .

Description of male holotype. Body length 29 mm. Body 1.1 times as long as greatest width (at coxae 3). Middorsal line without midposterior processes, not elevated in lateral view. Head, anterolateral margins concave, lateral corners acute and projecting anteriorly; width between anterolateral corners as wide as maximum span between lateral margins of eyes; head without paired processes on transverse ridge at bases of antennae 1, without paired tubercles between eyes, with small, blunt median posterior tubercle, with obscure lobes lateral to median posterior tubercle. Pereonite 1 lateral margin gently sinuous, lateral margin upturned over anterior half, obscurely duplicated, without submarginal ridge, dorsal surface with oblique-transverse ridge reaching near margin. Coxal dorsal plate 2 0.9 times as long as half pereonal tergite 2 width (following plates increasing in length); plate 4 1.3 times as long as half pereonal tergite 4 width; plate 6 extending beyond tip of pleotelson by 2.3 times middorsal length of pleotelson, the pair diverging over entire length, almost straight except at apex; pleonal epimeron 2 1.7 times length of pleotelson; pleonal epimeron 3 as long as pleotelson; pleonal epimera 2 and 3 with emarginate apices. Ventral coxal plates 2–4 with transverse ridges on mesial, anterior and posterior margins outlining a transverse depression. Antenna 1 peduncle articles 3+4 2 times as long as article 2 (anterior margin); flagellum of about 43 articles. Antenna 2 peduncle article 5 1.2 times as long as article 4; flagellum of 16 articles. Pereopod 1 propodus 2 times as long as greatest width. Pereopod 2 palm dorsal length 1.5 times greatest width, with short heel, straight setose proximal palm, convex distal palm, with 14 robust setae arranged in oval. Pereopod 7 carpus 3 times as long as greatest width; propodus 4.2 times as long as greatest width, propodus tapering from near base, lower margin straight; dactylus curved, 0.5 times as long as propodus. Pleopod 2 endopod with evenly tapering distal angle bearing appendix masculina; appendix masculina 3.8 times as long as straight margin of endopod. Uropodal exopod 0.85 length of endopod.

Female. Pereonite 1, lateral margin of female convex anteriorly, with distinct step-like interruption and straight posteriorly. Coxal dorsal plate 2 of female 0.5 times as long as half pereonal tergite 2 width; plate 4 of female 0.8 times as long as half pereonal tergite 4 width (following plates increasing in length); plate 6 of female extending beyond tip of pleotelson by 1.8 times middorsal length of pleotelson, the pair diverging over entire length, almost straight except at apex.

Size. Male length: 28 − 30 mm; female length: 27 − 30 mm.

Distribution. Tasman Sea, mid-Lord Howe Rise and Lord Howe Plateau, 31°'S − 37°'S, 159°E − 170°E, 1573 − 2096 m.

Etymology. This species is named for its distribution on the Lord Howe Rise.

Remarks. Brucerolis howensis is most similar to B. nowra ( Fig. 1f ), B. victoriensis and B. cidaris , all four with emarginate epimera apices. Brucerolis howensis can be distinguished by the combination of the weak projection of the anterolateral lobes of the head, the concave anterior margin and lack of submarginal sculpture on the dorsal surface of pereonite 1 and male epimeron 3 barely reaching (female epimeron 3 not reaching) the posterior margin of the telson.

Figures

Figure 1. Head and pereonite 1 of species of Brucerolis. a, B. brandtae sp. nov. (NMV J55313). b, B. bromleyana (syntype, BMNH 1889.4.27.20, negative of drawing by Kate Thompson published by Poore & Brandt, 1997). c, B. cidaris (NMV J27642). d, B. howensis (NMV J55315). e, B. hurleyi (NMV J55314). f, B. nowra (NMV J19213). g, B. osheai (NMV J55316). h, B. victoriensis (NMV J19201). Scale bar in each case = 10 mm.

Figure 6. Brucerolis howensis sp. nov. Holotype male (NIWA 27431): dorsal and lateral views, detail of front of head, sternites of pereonites 1–7, pleonites 1–3, medial ridge of pleonites 1–3, uropod. Paratype female (NIWA 27428): dorsal and lateral views, medial ridge of pleonites 1–3. Scales = 10 mm.