Spinosapseudes colobos, Błażewicz-Paszkowycz & Bamber, 2007

Błażewicz-Paszkowycz, M. & Bamber, R. N., 2007, New apseudomorph tanaidaceans (Crustacea: Peracarida: Tanaidacea) from eastern Australia: Apseudidae, Whiteleggiidae, Metapseudidae and Pagurapseudidae, Memoirs of Museum Victoria 64, pp. 107-148 : 126-127

Spinosapseudes colobos sp. nov.

Figures 10–13

Material. Female, holotype (NMV J55746), Australia, Victoria, central Bass Strait, 66 km S of Rodondo I. (39°49.30'S, 146°18.30'E), 82 m, 13/11/1981 (BSS 158 G), R.S. Wilson. Paratypes: 1 male, allotype ( NMVJ55745 ),samelocalityasholotype;10femaleswithoutoostegites , 5 males ( NMV J47125 ) , 1 female dissected, (J55944), same locality as holotype ; 1 female ( NMV J55767 ), Victoria, central Bass Strait , 26 km SE of Aireys Inlet (38°39.48'S, 144°18.12'E), 79 m, 19/11/1981, R.S. Wilson ; 5 females, 7 males, 17 juveniles ( NMV J55768 ), central Bass Strait , 100 km SSE of Cape Liptrap, Victoria (39°45.54'S, 145°33.18'E), 74 m, 13/11/1981, R.S. Wilson ; 3 females, 5 males, 2 mancas ( NVM J55769 ), central Bass Strait , 100 km SSE of Cape Liptrap, Victoria (39°45.54'S, 145°33.18'E), 74 m, 13/11/1981, R.S. Wilson ; 1 female ( NMV J55770 ), central Bass Strait, 65 km ENE of Cape Rochon, Three Hummock I. (40°10.54' S, 145°44.18' E), 75m, 13/11/1981, ( BSS 157 ), R.S. Wilson ; 1 male ( NMV J55771 ), Victoria, central Bass Strait , 26 km SE of Aireys Inlet (38°39.48'S, 144°18.12'E), 79 m, 19/11/1981, R.S. Wilson ; 4 female, 4 males ( NMV J55772 ), Tasmania, central Bass Strait, 47 km E of Cape Rochon, Three Hummock I. (40°23.48'S, 145°32.00'E), 66 m, 03/11/1980, ( BSS 113 ), M.F. Gomon and G.C.B. Poore ; 1 juvenile ( NMV J55773 ) Tasmania, central Bass Strait, 47 km E of Cape Rochon, Three Hummock I. (40°23.48'S, 145°32.00'E), 66 m, 03/11/1980, ( BSS 113 ), M.F. Gomon and G.C.B. Poore , 4 females, 5 males, 8 mancas ( NMV J55775 ), eastern Bass Strait, 63 km E of North Point, Flinders I. (39°44.48'S, 148°40.36'E), 124 m, 14/11/1981, ( BSS 167 ), R.S. Wilson ; 1 male ( NMV J55774 ) eastern Bass Strait , 20 km SSW of Babel I. (40°06.48'S, 148°24.18'E), 22 m, 14/11/1981, ( BSS 166 ), R.S. Wilson .

Description of female. Body dorsoventrally flattened, elongate, holotype 9.5 mm long (tip of rostrum to posterior of pleotelson), 6.7 times as long as wide, narrower posteriorly. Cephalothorax subrectangular, 1.2 times as long as wide, anterior margin with conspicuous pointed rostrum with rounded “shoulders” at base. Eyes present; eyelobes modified to prominent spine-like apophyses directed anterolaterally; conspicuous lateral spiniform apophyses at anterior margin of branchial chambers. 6 free pereonites; pereonites 1 and 2 subequal, about 0.4 times as long as cephalothorax, lateral margins uniformly convex; pereonite 3 as long as pereonite 2, with anterolateral spine-like apophyses and expanded posterolaterally at attachment of coxae; pereonites 4, 5 and 6 subequal (4 longest), 1.2 times as long as pereonite 2, with anterolateral spine-like apophyses and expanded posterolaterally at attachment of coxae (all pereonites respectively 2.3, 2.0, 1.6, 1.3, 1.25 and 1.25 times as wide as long); ventral hyposphenia present on all pereonites. Pleon 3.6 times as long as pereonite 6, of 5 free subequal pleonites bearing pleopods plus pleotelson; pleonites 2.54 times as wide as long, laterally expanded by spiniform apophyses. Pleotelson long and slender, almost half length of whole pleon, 2.8 times as long as wide, lateral margins undulating, with paired distal setae.

Antennule peduncle article 1 elongate, 3.7 times as long as wide, setose as figured, inner margin finely corrugated; article 2 0.3 times as long as article 1, with 2 groups of inner marginal setae and tuft of outer distal setae, longest of these longer than article; article 3 half length of article 2, with long outer seta; article 4 half as long as article 3, with inner distal seta. Main flagellum of 15 segments, segments 10, 12 and 13 bearing aesthetascs; accessory flagellum of 6 segments.

Antenna peduncle article 1 simple; article 2 twice as long as wide, with proximal inner and outer marginal denticulations and 2 outer setae, and bearing elongate squama with 16 marginal setae; peduncle article 3 as long as wide, with 1 seta; article 4 slightly longer than article 5, and 3 times as long as article 3, with inner penicillate seta; article 5 with outer penicillate seta and simple and penicillate setae at inner distal corner. Flagellum of 11 segments.

Mouth parts. Labrum rounded, simple setose. Right mandible with outer margin finely denticulate, bearing strong, crenulated pars incisiva, setiferous lobe with 7 distally compound setae and 1 simple seta, pars molaris robust, blunt, distally with marginal spinules; mandibular palp of 3 articles, article 1 just longer than wide with row of 5 inner setae; article 2 5 times as long as wide with 2 parallel rows of inner simple setae in distal 3rd and row of 4 mesial setae in distal half; article 3 about two-thirds as long as article 2 with row of inner simple setae increasing in length towards distal end of article, 3 distal mesial setae, and 3 longer distal setae. Left mandible as right but with crenulate lacinia mobilis. Maxillule inner endite marginally setose with outer blunt apophysis, distally with 5 plumose spines; outer endite with 1 shorter (“dwarfed” sensu Lang, 1968) and 12 longer stout and blunt distal spines and 2 subdistal setae, outer and inner margins finely setose; palp of 2 articles, distally with 7 setae.Maxilla with microtrichia on outer margin; outer lobe of outer endite with 2 setae with mid-length setulation on outer margin, distally with 9 similar setae; inner lobe of outer endite with curved simple setae; outer lobe of inner endite with setulose spines distally and subdistally; inner lobe of fixed endite with rostral row of numerous setae guarding 10 longer setae with mid-length setulation, innermost seta finely bilaterally denticulate. Labium with setulose distal margin, palp with conspicuous lateral setules and 3 fine distal setae. Maxilliped basis irregularly serrated on outer distal margin and with 2 inner distal plumose setae; palp article 1 with 2 outer distal setae and 2 plumose inner setae; palp article 2 longer than wide, with rows of numerous shorter simple and longer plumose setae on inner margin, outer margin with simple strong distal seta; palp article 3 longer than wide, with numerous simple setae along expanded inner margin; palp article 4 with 13 distal setae. Endite with 4 coupling-hooks, simple outer distal setae, simple whip-like inner caudodistal seta and stout, spatulate, distal spines (“chitinous formations” sensu Lang, 1968). Epignath not seen.

Cheliped relatively slender. Basis 1.75 times as long as wide, dorsally with spine-like apophysis in distal half, ventrally with proximal setae, midventral spine and tuft of 5 distal setae; exopodite present, 3-articled, distal article with 6 setae. Merus elongate, with paired dorsal and 3 mid-ventral setae, ventrodistal spine-like apophysis amongst tuft of setae. Carpus more than 3 times as long as wide, with row of setae along ventral margin mostly longer than carpal width, 1 proximal and 2 distal simple setae on dorsal margin. Chela fingers about as long as palm, ventral margin with 10 setae, 7 distal setae around claw of fixed finger; 3 setae near articulation of fixed finger; dactylus slender, as long as fixed finger, distal claw pointed.

Pereopod-1 with pronounced spine-like apophysis on coxa. Basis stout, 2.8 times as long as wide, with ventral setae in proximal half, tuft of ventrodistal setae and short spine; exopodite present, 3-articled, article 3 with 5 distal setae. Ischium with 5 simple ventrodistal setae. Merus two-thirds as long as basis, with rows of 7 ventral setae and 4 fine outer mesial setae, 4 dorsodistal simple setae, ventrodistal spine. Carpus shorter than merus, with dorsodistal spine adjacent to group of long simple setae, and ventrally with 2 spines in distal 0.5 interspersed with simple setae. Propodus half as long as carpus plus merus, with 2 dorsal spines, longer dorsal setae, 4 ventral spines. Dactylus slender, about 0.7 length of propodus, with ventral denticulations; unguis short.

Pereopod 2 more slender, basis 3.9 times as long as wide. Merus 0.9 times as long as carpus, with elongate setae along ventral margin, but restricted to distal corner dorsally. Carpus elongate, with rows of ventral and dorsal setae. Propodus just shorter than carpus, similarly setose but with 1 submarginal dorsal and ventrodistal spine. Dactylus slender with fine subdistal seta, with unguis and dactylus as long as propodus.

Pereopod 3 similar to pereopod 2, but basis with longer marginal setae, carpus and propodus with mesial spines.

Pereopod 4 coxa with spine-like apophyses, basis 3.6 times as long as wide, with penicillate setae, merus with sinuous dorsal margin and 2 ventral spines amongst longer setae, carpus 1.7 times as long as merus with ventral and distal spines and setae, distal setae more than half as long as propodus; propodus shorter than carpus, with proximo-dorsal penicillate seta, subdistal and distal rows of short setae, 4 longer distal setae exceeding unguis; dactylus plus unguis shorter than propodus.

Pereopod 5 similar to pereopod 4, coxa with apophyses, distal short setae forming a crown around tip of propodus.

Pereopod 6 similar to pereopod 5, but basis with rows of marginal setae, ventrally simple but dorsally plumose; merus with single plumose dorsal seta; carpus with simple dorsal marginal setae; propodus with ventroproximal and mesial short spines, row of fine leaf-like spines around dorsal margin and along distal two-thirds of ventral margin.

Pleopods all alike. Basis with 4 inner (ventral) plumose setae. Endopod longer than exopod without proximal articulation; both rami slender, with numerous marginal plumose setae. Inner proximal seta on endopod more robust.

Uropod biramous, both rami filiform, multi-segmented. Basis with row of outer setae; exopod one-fifth as long as endopod, with 7 segments; endopod elongate, with about 40 segments.

Male. Slightly larger than female (dissected specimen 10.3 mm long); sexual dimorphism shown by an increased number of aesthetascs on the antennule, and large ventral penial tubercle on pereonite 6. Cheliped more robust, basis 1.5 times as long as wide; carpus subtriangular, only slightly longer than wide; propodus stout, longer than carpus plus merus, fixed finger with conspicuous proximal tooth-like apophysis on cutting edge; dactylus with smaller proximal apophysis on cutting edge.

Etymology. From the Greek kolobos – shortened, with reference to the articles of the antennular and antennal peduncles and mandibular palp, and the pereopod bases, being conspicuously shorter than those of the generotype S. setosus ( Lang, 1968) .

Remarks. Of the numerous species attributed to the genus Apseudes sensu lato (including Spinosapseudes Guţu, 1996 and Tuberapseudes Băcescu and Guţu, 1971 ), only 13 have a conspicuous spine-like apophysis anterior to the branchial chamber, and, apart from A. bruneinigma Bamber, 1999 , all have a telson at least twice as long as wide and anterolateral spine-like apophyses on pereonites from 3 to 6. Only 5 of these, A. abyssalis Błażewicz-Paszkowycz and Larsen, 2004 , A. rotundifrons Băcescu, 1981 , A. tenuimanus Sars 1882 , A. (Tuberapseudes) echinata Sars 1882 , and A. setosus Lang, 1968 , have no dorsodistal spine on the merus of pereopod 1, and of these only A. setosus has the combination of a strongly pointed rostrum, more than 5 segments in the antennule accessory flagellum, and ventral but no dorsal setae on the pleopod basis.

Guţu (1996) erected the genus Spinosapseudes for A. setosus Lang, 1968 (until now monotypic), named after the large spine-like apophyses on the cephalon and pereonites, and on the coxae of the posterior pereopods, and distinguished by the morphology of pereopod 1 being more similar to that of Carpoapseudes species, rather than the fossorial (i.e. apparently adapted for digging) appearance of this pereopod in Apseudes sensu stricto (as in the type species A. talpa Montagu, 1808 ).

While the present species shows a more fossorial morphology to its pereopod 1, it has numerous features in common with Spinosapseudes setosus , notably the coxa l apophyses of the posterior pereopods, but also the plumose dorsal setae on pereopod 6, the spine-like apophyses of pereonites 3 to 6 and of the cheliped merus, the chaetotaxy of the mouthparts and pleopods, and the number of segments in antennular and antennal flagella and uropod exopod. Spinosapseudes colobos sp. nov. is accordingly placed in the same genus, but, in addition to the pereopod 1 morphology, is clearly distinguished from S. setosus by the proportionately more compact articles of the antennular and antennal peduncles, the mandibular palp and the pereopods. Both species are only known from the Tasman Sea – Bass Strait region.