Protanaissus huberti, Błażewicz-Paszkowycz & Bamber, 2012

Błażewicz-Paszkowycz, M. & Bamber, R. N., 2012, The Shallow-water Tanaidacea (Arthropoda: Malacostraca: Peracarida) of the Bass Strait, Victoria, Australia (other than the Tanaidae), Memoirs of Museum Victoria 69, pp. 1-235 : 193-197

Protanaissus huberti sp. nov.

Figures 130–132

Material examined. 1 (J50812), holotype, Stn VC 41 C3, Eastern Bass Strait, 37º32.95'S 148º03.78'E, 40 m depth, 08 May 1998, coll. N. Coleman , Smith-McIntyre Grab. 1 (J51796) , paratype dissected, Stn VC 40 C1, Eastern Bass Strait, 37º35.42'S 147º31.88'E, 40 m depth, 08 May 1998, coll. N. Coleman , Smith-McIntyre Grab. 1 (J48971) , paratype, CPBS 32 N/810, Western Port off Crib Point, 38º20.83'S 145º13.49'E, 13 m depth, sandy gravel, 12 August 1970, coll. A.J. Gilmour. 1 (J55829), paratype dissected, Stn VC 18 C2, Central Bass Strait, 38º30.2'S 144º15.0'E, 40 m depth, 13 May 1998, coll. N. Coleman , Smith-McIntyre Grab. 1 (J48980) , paratype, CPBS 32 S/770, Western Port off Crib Point, 38º21.6'S 145º13.67'E, 13 m depth, muddy sand, 06 July 1970; coll. A.J. Gilmour. 1 (J48919), paratype, CPBS 300 /770, Western Port off Crib Point, 38º21.15'S 145º13.51'E, 15 m depth, fine sand with mud, 06 July 1970, coll. A.J. Gilmour.

Description of female. Body ( Fig. 130) slender, parallel-sided, seven times as long as wide, holotype 1.3 mm long. Cephalothorax longer than pereonites 2 and 3 combined, 1.3 times as long as wide, rostral half narrower than posterior. Pereonites all rectangular with convex lateral margins, pereonite1 shortest, 0.25 times as long as cephalothorax; pereonites 2, 3 and 6 subequal, 1.7 times as long as pereonite 1; pereonites 4 and 5 subequal, 2.4 times as long as pereonite 1 (all pereonites respectively 2.5, 1.5, 1.5, 1.1, 1.1 and 1.6 times as wide as long). Pleon 2.5 times as long as pereonite 6; pleonites subequal in length, four times as wide as long, all bearing pleopods; pleotelson semicircular, as long as two preceding pleonites, 1.8 times as wide as long.

Antennule ( Fig. 131A) slender, as long as cephalothorax, three–articled; article 1 four times as long as wide, 1.5 times as long as articles 2 and 3 combined, with mid-dorsal and dorsodistal tufts of penicillate setae, and single mid-length and distal simple inner setae; article 2 twice as long as wide, 0.4 times a slong as article 1, with single inner and outer simple distal setae; article 3 twice as long as wide, 0.7 times as long as article 2, with five simple distal setae and one aesthetasc.

Antenna ( Fig. 131B) six–articled, article 1 short and annular, article 2 more than twice as long as article 1, 1.5 times as long as wide, with dorsal seta; article 3 half as long as article 2, with dorsal seta; article 4 longer than articles 1 to 3 combined, 5.6 times as long as wide, curved, with two simple and three penicillate distal setae; article 5 as long as article 1, 1.5 times as long as wide, with long distal seta; article 6 very small, with two setae.

Labrum ( Fig. 131C) rounded, hood-shaped, naked. Left mandible ( Fig. 131D) with triangular incisor serrated on anterior border, and broader denticulate lacinia mobilis, molar gently curved, tapering to narrow tip with spinules but no grinding surface; right mandible ( Fig. 131E) with finely denticulate distal margin and bifid incisor; molar as on left mandible. Labium not recovered. Maxillule ( Fig. 131F) endite sigmoid, with two distal setules and six longer and two shorter terminal spines; palp not recovered. Maxilla ( Fig. 131G) wide, rounded, naked. Maxilliped ( Fig. 131G) basis fused, with long seta near articulation with palp almost reaching distal margin of palp article 3; palp setae simple, article 1 naked; article 2 with outer distal seta, three inner-distal setae, longest of which exceeds tip of palp; article 3 with four unequal inner distal setae; article 4 with two subdistal and four distal setae; endites basally fused, distally wide, inner distal margin with one short and one linguiform tubercles. Epignath not recovered.

Cheliped ( Fig. 131H) basis with rounded posterior free margin, 1.6 times as long as wide, with small laterodistal seta; merus subtriangular, with ventral seta; carpus 1.8 times as long as broad, with one dorsoproximal, one dorsodistal and two mid-ventral setae; chela about as long as carpus, stout, resembling that of Tanaissus spp. , propodus wider than long with dorsodistal rugosity; fixed finger robust, proximally wide, with convex denticulate cutting edge, one ventral seta and three setae near cutting edge; dactylus with dorsal rugosity in proximal half.

Pereopod 1 ( Fig. 132A) longer and more slender than pereopods 2–3; coxa without seta; basis five times as long as wide, sinuous; ischium with small seta; merus 0.3 times as long as basis, naked; carpus 1.7 times as long as merus, naked; propodus 1.2 times as long as merus and carpus combined, with small dorsodistal spine-like apophysis and fine ventral subdistal seta; curved dactylus 0.8 times as long as curved unguis, both together as long as propodus. Pereopod 2 ( Fig. 132B) stouter than pereopod 1, coxa with fine seta; basis 3.6 times as long as wide, with one dorsoproximal simple seta; ischium with one seta; merus distally wider, one-quarter as long as basis, with one slender ventrodistal spine; carpus 1.8 times as long as merus, with one slender ventrodistal spine; propodus as long as carpus, with one ventrodistal seta; dactylus shorter than unguis, both together as long as propodus. Pereopod 3 ( Fig. 132C) similar to pereopod 2, but coxal seta longer, basis naked, ventrodistal spine on carpus larger (more than half as long as carpus), propodus with some distal microtrichia.

Pereopod 4 ( Fig. 132D) basis 2.9 times as long as wide; ischium with two setae; merus 0.4 times as long as basis, with two ventrodistal spines; carpus as long as merus, with single ventral, outer and inner distal spines and dorsodistal spinule; propodus 1.1 times as long as carpus, with dorsal microtrichia in distal half, one dorsodistal seta exceeding length of dactylus plus unguis, and ventrodistal spine almost as long as dactylus; dactylus and very short bifurcate unguis together half as long as propodus. Pereopod 5 ( Fig. 132E) similar to pereopod 4, merus somewhat shorter. Pereopod 6 ( Fig. 132F) similar to pereopods 4 and 5 but propodus with two shorter and one longer dorsodistal setae, no ventrodistal seta or spine.

Pleopods all similar ( Fig. 132G), basal article about as long as wide, naked; endopod and exopod rami similar, but endopod somewhat shorter, with five outer-distal and one inner-subdistal plumose setae; exopod with seven outer-distal and one separated outer proximal plumose setae.

Uropod ( Fig. 132H) slender; basal article naked; exopod two-segmented, just longer than proximal article of endopod, segments subequal in length, with one distal seta on proximal segment, two unequal distal setae on distal segment; endopod two–segmented, segments subequal in length, proximal segment with two inner penicillate distal setae, distal article with one subdistal and three distal simple setae.

Male. Unknown.

Etymology. This species is dedicated to the first author’s son and the second author’s good friend, Hubert.

Remarks. Protanaissus huberti sp.nov. shows many similarities to P. longidactylus , including the elongate distal articles of pereopod 1, the rugose cheliped, the conformation of the mouthparts, particularly the wide maxilliped endites, and the long dorsodistal setae on the propodi of the posterior pereopods. It is distinguished from P. longidactylus in having the distal antennular article shorter than the second article (approaching twice as long in P. longidactylus ), the more compact fifth article of the antenna, the presence of distal spinules on the mandibular molar process, the presence of linguiform distal tubercles on the maxilliped endites, in having only one ventrodistal spines on the merus and carpus of pereopods 2 and 3, only one ventral seta on the cheliped propodus (two in P. longidactylus ), serrations along the whole cutting edge of the fixed finger of the cheliped propodus (only distally serrate in P. longidactylus ) and in having only one ventrodistal seta on the propodus of the posterior three pairs of pereopods (or none on pereopod 6) compared with two in P. longidactylus .

Protanaissus huberti was taken occasionally throughout the eastern and central Bass Strait at depths between 13 and 40 m.

The second species to have been attributed to Protanaissus was P. makrotrichos Sieg 1986 , from the shelf off Argentina, which showed many similarities to P. longidactylus , but had a distal grinding (“triturating”) surface on the mandibular molar process, no rugosity on the cheliped, and a maxilliped endite distally folded to fuse with the basis giving the appearance of two narrow lobes; rather than having a long dorsodistal seta on the propodus of pereopod 6, P. makrotrichos has a long ventrodistal seta. Guţu (1996c) described P. alvesi from Brazil, which, while again similar to P. longidactylus , also had a distal grinding surface on a stout (not tapering) mandibular molar process, no rugosity on the cheliped, no very long seta on maxilliped palp article 2, a maxilliped endite apparently distally narrow, and a long ventrodistal seta on the propodus of pereopod 6, thus more similar to P. makrotrichos . Finally, Larsen and Heard (2004a) described P. floridensis from Florida, a species with a uniformly narrow mandibular molar process, rugosity on the cheliped, and distally narrow (but not infolded or fused) maxilliped endites, as well as a one-segmented uropod exopod, a uropod endopod without conspicuous pair of penicillate setae on the proximal segment, no very long seta on maxilliped palp article 2, the dactylus plus unguis of pereopods 4 to 6 fused into a claw, no long distal seta on the propodus of pereopod 6, and a quite distinct pereopod 1, with the propodus shorter than the merus and carpus combined, and a dactylusplus-claw about half as long as the propodus.

That these three additional species have a distally-narrowed maxilliped endite, that two of them have a grinding mandibular molar and no cheliped rugosity, while the third has a quite distinct pereopod 1 and apparently fused claws on pereopods 4 to 6, inter alia, puts them in conflict with the generic diagnosis given above. Conversely, the new Australian species, Protanaissus huberti , described above agrees with the generic diagnosis in all respects.

We therefore remove Protanaissus makrotrichos and P. alvesi to a separate genus, clearly close to Protanaissus , while P. floridensis is moved to yet another distinct genus, no closer to Protanaissus than it is to Tanaissus . These genera are defined below.