A new genus and new species of Desmosomatidae (Crustacea: Isopoda: Asellota) from the deep sea of south-eastern Australia Author Brix, Saskia text Memoirs of Museum Victoria 2006 2006-12-31 63 2 175 205 https://museumsvictoria.com.au/collections-research/journals/memoirs-of-museum-victoria/volume-63-issue-2-2006/pages-175-205/ journal article 10.24199/j.mmv.2006.63.15 1447-2554 10665816 Disparella kensleyi sp. nov. Figures 11–14 Material examined. Holotype . Female , preparatory, 1.9 mm ; NMV J18605 ; Type locality. - Australia , NSW, 74 km E of Nowra ( 34°56.11'S , 151°28.06'E ), 3150 m , box corer, G.C.B. Poore et al, RV Franklin , 23 Oct 1988 (stn. SLOPE 64 ). Diagnosis. Body length 3.98 times longer than width of pereonite 2. Pereonite 1 length 1.05 pereonite 2 length, 0.93 pereonite 2 width. Pereonite 5 with spine-like ventral elongation. Cephalon with 1 short anteriorly directed spine at insertion of antennae. Palp of mandible of 2 articles, article 1 with 1 small seta, article 2 terminally with 1 small seta. Incisior process with 4 teeth. Lacinia mobilis of left mandible with 4 teeth. Carpus of pereopod I length 5 times width, with ventral row of 5 long unequally bifid setae increasing in length towards the propodus and 3 setal combs inserted in a cuticular membrane, dorsally with 2 long simple setae. Pleotelson with posterolateral spines. Distal margin of operculum slightly concave, with 6 slender setae. Uropods biramous, exopod length 0.43 endopod length. Description. Habitus : body 1.9 mm long (measured without appendages), 3.98 times longer than width of pereonite 2. Pereonite 5 with spine-like ventral elongation. Cephalon with 1 short anteriorly directed spine at insertion of antennae. Pereonite 1 slightly wider than cephalon. Pereonite 1 length 1.05 pereonite 2 length, 0.93 pereonite 2 width. Pereonite 5 anterior margin straight, lateral margins slightly concave. Coxae 1–4 produced, tipped with small stout setae. Pleotelson length 0.71 width, posterolateral spines present, lateral margins convex, posterior margin rounded. Antennula : 0.3 mm long, length 0.16 body length, with 5 articles. Article 1 with 3 small broom setae. Article 2 length 3.83 width, 1.64 article 1 length; distally with 2 large articulated broom setae. Article 3 with 1 small slender seta, article 4 distally with 2 small broom setae, distal article terminally with 1 aesthetasc, 1 broom seta and 2 long slender setae. Antenna : About 1.1 mm long, length 0.58 body length, with about 12 articles (broken off after article 12). Article 3 with 2 small slender setae. Article 4 with 2 slender setae. Article 5 with 3 small slender setae. Article 6 marginally with 2 and distally with 3 slender setae. Flagellar articles 1–3 distally with 2 slender setae, following articles with long slender setae. Mandible : Palp of 2 articles, article 1 with 1 small seta, article 2 terminally with 1 small seta. Incisior process with 4 teeth. Lacinia mobilis of left mandible with 4 teeth, lacinia mobilis of right mandible triangular and distally serrated (5 small teeth). Spine row containing 3 spines. Molar process with 7 setae. Maxillula : Inner lobe smaller than outer lobe (0.71 of outer lobe length), terminally with 5 setae. Outer lobe 5 times longer than wide, marginally with 3 pairs of fine setae, terminally with 9 strong spines and 4 simple setae. Maxilla: Not dissected from specimen. Maxilliped : Epipodite length 3.13 width, length similar endite length. Endite with 2 coupling hooks, terminally with 2 conate setae and 5 small setae, marginally few fine setae. Outer edge of endite and palp articles 1 and 2 with row of fine setae and 1 small seta on distal corners, inner margin of article 3 with 5 setae, outer margin with 1 seta, article 4 with 3 setae, article 5 with 2 setae. Article 1 length 0.6 width, article 2 length 0.93 width, article 3 length 1.07 width, article 4 length 2.5 width, article 5 length 3 times width. Pereopod I : Basis length 4.04 width, proximal to ischium ventrally 1 long simple seta. Ischium length 0.63 width, ventrally 1 small slender seta. Merus length 0.71 width, dorsally 2 robust simple setae, ventrally 1 seta (broken off). Carpus length 1.43 width, ventrodistally with large claw-seta and slender proximal seta, ventrally 1 small seta midway. Propodus length 3.47 width, ventrally fringed with fine setae and row of 12 small setae inserted in a cuticular membrane. Dactylus length 7.6 width, mediodistally 1 small seta. Unguis (claw) of dactylus with 1 cuspidate and 1 conate seta, 2 slender setae medially. Pereopod II : Similar to pereopod III and pereopod IV. Basis length 6.33 width, marginally with few simple setae and 1 small broom seta, proximal to ischium ventrally with 1 long simple seta. Ischium length 2.62 width, distodorsally with 1 seta, ventrally 1 seta midway. Merus length 1.45 width, distoventrally with 1 stout unequally bifid seta and 2 small slender setae, distodorsally 1 composed seta. Carpus length 5 times width, with ventral row of 5 long unequally bifid setae increasing in length towards the propodus and 3 setal combs inserted in a cuticular membrane, dorsally with 2 long simple setae. Propodus length 5.38 width, ventrally with 1 small slender seta midway, fringed with fine setae, dorsally 2 long simple setae and distally 1 small broom seta. Dactylus length 6.67 width, mediodistally 2 small setae. Unguis (claw) of dactylus with 1 conate seta, 2 slender setae ventrally. Pereopod V : Similar to pereopod VI and pereopod VII . Basis length 6.30 width, marginally with 1 small and 2 broom setae. Ischium length 4.10 width. Merus length 1.60 width, with 3 slender setae. Carpus length 4.80 width, with ventral row of 5 long slender setae and dorsally 2 long setae (broken off), distally 1 small slender seta and 1 small broom seta. Propodus length 4.13 width, ventrally with 1 small seta and 3 long slender setae, dorsally with 2 slender setae. Dactylus length 7.60 width, mediodistally 3 small setae, unguis (claw) of 1 long conate seta, 2 slender setae inserting ventrally. Pleopod 2 (operculum):Length1.19width.Lateralmargins slightly convex, distal margin slightly concave, distal margin with 6 slender setae. Pleopod 3 : Endopod length 1.44 width, distally with 3 long plumose setae. Exopod length 0.74 of endopod length, with 1 small terminal seta, outer margin hirsute. Pleopod 4 : Endopod length 2.66 width. Exopod length 8 times width, distally with 1 long plumose seta. Uropods : Biramous. Endopod length 3.5 protopod length, 4.66 times longer than wide, distally with 5 broom setae, 2 small slender setae and 2 long slender setae. Exopod length 0.43 endopod length, 4 times width, terminally with 2 slender setae. Protopod length similar width, with 1 slender seta. Etymology. The name is in remembrance of Dr Brian Kensley. Distribution. Off NSW, Australia . Discussion. Disparella kensleyi sp. nov. shows affinity to species of Chelator and Prochelator Hessler, 1970 . The chela of the new species is similar to the chela as found in Chelator (ventral margin of carpus with small setae only), but Chelator species possess uniramous uropods and a lacinia mobilis with three teeth. A single midventral seta on the carpus together with the claw-seta and the penultimate slender seta is also known for the genus Prochelator but in Prochelator species the midventral seta is always of composed setal type . Due to the anteriorly directed spine at the antennular folds, which is known for all species of Disparella , and the biramous uropods, D. kensleyi fits best into Disparella . It is distinguished from the other members of the genus by the spine-like ventral elongation at pereonite 5 and the single small midventral seta on the carpus of pereopod I together with the claw-seta and the penultimate slender seta.