Pagurapseudes victoriae, 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 : 64-69

Pagurapseudes victoriae sp.nov.

Figures 41–44

Material examined. 1 brooding (J57789), holotype, Stn CPBS 03 N, Western Port , 38º20.56'S 145º15.08'E, 2 m depth, 5 April 1965; 3 (1 brooding), 1 (J57790), paratypes, same sample as holotype; 2 (J48009), paratypes, Stn CPBS 25 S, Western Port, 38º21.63'S 145º15.08'E, 9 m depth, 23 February 1965, sand; 1 with oostegites, 2

(J48004), paratypes, Stn CPBS 11 S, Western Port, 38º22.00'S 145º13.38'E, 3 m depth, 17 March 1965, shelly gravel; 3 (J56614), 2

(56612), paratypes, 95 further specimens (unregistered), Stn PPBES 985 , Port Phillip Bay, 38º21.00'S 144º41.5'E, 9 m depth, 9 December 1971, sand; 3 (J43098) , paratypes, Port Phillip Bay “wet sandy region”, 38º10.51'S 144º43.9'E, 7.5 m depth, 17 October 1994, sand (labelled “ P. spinipes ”); 2 (J56618) , paratypes, 1, 4 (unregistered), Stn BSS180 , Central Bass Strait, 39º12.9'S 146º27.3'E, 65 m depth, 18 November 1981, medium sand, coll. R. S. Wilson; 5 (J56617) , paratypes, 10 (unregistered), Stn BSS170 , Eastern Bass Strait, 31º51.8S 148º26.5'E, 130 m depth, 15 November 1981, fine sand, coll. R. S. Wilson; 1 brooding, 1 (J56613) , paratypes, Stn BSS209 , Eastern Bass Strait, 38º18.0'S 147º37.0'E, 55 m depth, 31 July 1983, muddy fine shell, coll. M. Gomon & R. S. Wilson .

Other material. A further 447 specimens from the Tasmanian Coast, Flinders Island, Western Port , Port Phillip Bay and throughout the Bass Strait , at depths from 5 to 69 m.

Description of female. Body ( Fig. 41A) typical of a pagurapseudid, pleon skewed to the right and curved under pereon; small, holotype about 5 mm long. Cephalothorax ( Fig. 41B) subrectangular, as long as wide, rostrum variable ( Fig. 42): often trilobed, anterior margin either smooth ( Fig. 42A), or with fine ( Fig. 42B) or coarse ( Fig. 42C) denticulation, this variation irrespective of gender or maturity; lateral margins of branchial chamber with 8 or 9 plumose setae, sparse plumose setae scattered over dorsal surface of branchial chambers. Eyelobes distinguished with anterior pointed apophysis, eyes present as group of black-pigmented ocelli. Epistome not visible dorsally. Each pleonite with anterolateral and posterolateral tufts of plumose setae; pereonite 1 shortest, 0.3 times as long as cephalothorax; pereonite 2 1.4 times as long as pereonite 1; pereonite 3 longer, pereonite 4 longest, nearly twice as long as pereonite 1; pereonites 5 and 6 progressively shorter, pereonite 6 just longer than pereonite 2 (all pereonites respectively 3.0, 2.0, 1.4, 1.3, 1.4 and 1.5 times as wide as long). Pleon with five free subequal, asymmetrical pleonites, each pleonite about one-third as long as pereonite 6, with sparse lateral and occasional dorsal plumose setae. Pleonites 1 to 3 only bearing pleopods. Pleotelson almost semicircular, longer than last two pleonites together, just shorter than wide, with sparse plumose lateral setae and simple distal setae.

Antennule ( Fig. 43A) proximal peduncle article 3.25 times as long as wide, with conspicuous inner-distal tridentate apophysis and inner-medial expansion bearing tooth-like apophyses and two plumose setae; outer margin also denticulate, each “tooth” with an adjacent plumose seta. Second peduncle article 0.3 times as long as first, expanded distally to 1.5 times as long as wide, with plumose distal setae; third article as long as second, fourth article one-third length of third. Main flagellum of five (rarely six) segments, with single aesthetascs on each segment; accessory flagellum of two (rarely three) segments, distally not quite reaching distal edge of third segment of main flagellum.

Antenna ( Fig. 43B) with two basal articles fused into wide proximal peduncle article inner margin bearing denticulation and distal apophysis and two plumose and three penicillate setae, outer margin with blunt apophysis; third article as long as wide, 0.4 times as long as fused basal articles, with single simple seta; fourth peduncle article half as long as fused basal articles, naked; fifth article just longer than fourth, with one simple and four penicillate distal setae. Flagellum of two segments, distal segment with three distal setae.

Labrum ( Fig. 43D) bilobed, rounded, sparsely setose, small pointed epistome present ( Fig. 43C). Left mandible ( Fig. 43E) with finely denticulate outer margin, quadricuspid pars incisiva, tricuspid lacinia mobilis, setiferous lobe with simple and bifurcate setae, pars molaris round, blunt, with ventrodistal spinules on grinding surface; palp of three articles, proximal article with robust, plumose inner seta, second article longest, twice as long as proximal article, with 13 inner distally-denticulate setae in distal half; third article two-thirds as long as second, with nine progressively longer distally-denticulate setae along inner margin, distal seta longer than article. Right mandible as left but without lacinia mobilis ( Fig. 43F). Labium ( Fig. 43I) typically marginally setose, palp with two strong distal setae, fine outer setules and longer inner setae. Maxillule ( Fig. 43G) inner endite with five plumose distal setae outer apophysis and row of simple setae, inner margin with fine setules; outer endite with ten distal spines, inner and outer margins setose; palp ( Fig. 43 G') of two articles with distinct articulation, distally with three setae each bearing rounded setulose tips. Maxilla ( Fig. 43H) outer margin setulose, outer lobe of moveable endite with two subdistal and seven distal finely setulose setae, inner lobe with four simple and four setulose setae; fixed endite outer lobe with two bifurcate, two trifurcate, two setulose and three bilaterally denticulate distal spines, inner lobe with four longer plumose setae and rostral row of 20 setae. Maxilliped ( Fig. 43K) basis with seven distal plumose setae, inner margin with two rows of denticulation and plumose seta; proximal palp article with simple outer margin with one plumose and one simple setae, and short spine, inner margin naked; second article with coarsely denticulate inner and outer margins, three plumose seta on outer margin, two shorter simple setae and five plumose setae along inner margin; third article widening distally, with coarsely denticulate outer margin, six inner simple setae; fourth article with ten distal and outer sub-distal setae each with fine denticulation in distal half; endite (not figured) with finely setose outer margin, simple distal spines, three coupling-hooks. Epignath ( Fig. 43J) large, inner lobes conspicuous, distal spine proximally setose.

Chelipeds ( Fig. 44A) showing no conspicuous dimorphism. Compact basis 1.3 times as long as wide, with complex proximal surface denticulations dorsally and ventrally, three mid-ventral simple setae, one simple and two plumose subdistal ventral setae; exopodite absent. Merus quadrate, distal half of ventral margin with coarse denticulation, three inner and one ventral subdistal plumose setae and four mid-ventral simple setae. Carpus elongate, twice as long as wide, widening distally, with denticulate inner margin, sparse dorsal and ventral marginal fine setae, two plumose and one simple inner proximal setae. Propodus elongate, 2.1 times as long as wide, with few ventral setae; fixed finger with four ventral setae, three setae adjacent to cutting edge, saw-like row of small tooth-like spines distally on cutting edge ( Fig. 44 A'); dactylus curved, cutting-edge with fine denticulations and three distal tooth-like spines ( Fig. 44 A').

Pereopod 1 ( Fig. 44B) longest pereopod, coxa with slight apophysis having denticulate margin and one simple and one plumose setae; basis 2.3 times as long as wide, dorsal margin bearing seven plumose setae interspersed amongst triangular tooth-like apophyses with further four submarginal plumose setae, ventral margin with four ventral and one distal plumose setae, two simple ventrodistal setae; exopodite present ( Fig. 44 B'), large, distal article with seventeen plumose setae. Ischium one-quarter as long as basis, with mid-dorsal simple seta, ventrally with one plumose and two simple distal setae. Merus 0.8 times as long as basis, dorsally with two distal setae, ventral margin with plumose setae and distal spine. Carpus shorter than merus, with four ventral spines, each with crenulate anterior face, interspersed with setae. Propodus 1.4 times as long as carpus, with five ventral spines. Dactylus curved, 0.8 times as long as propodus, with fine ventral setae, unguis slender, sharp, 0.4 times as long as dactylus.

Pereopods 2 to 6 similar to each other, each about one-half to one-third as long as pereopod 1. Pereopod 2 ( Fig. 44C) basis stout, 2.2 times as long as wide, with one plumose and two penicillate dorsoproximal setae, simple ventrodistal seta; ischium with three ventrodistal setae. Merus, carpus and propodus bearing “sucker-like” spines, generally in two ventral rows, and plumose setae as figured. Merus longer than carpus; propodus 0.8 times as long as carpus, distal propodal spine simple, stout; dactylus and unguis not fused into hook-like claw, dactylus with minute inner distal spine. Pereopod 3 ( Fig. 44D) with more plumose setae on basis, no dorsal seta on merus. Pereopod 4( Fig. 44E) basis stouter, 1.7 times as long as wide, fewer “sucker-like” spines on merus, without stout distal propodal spine. Pereopod 5 ( Fig. 44F) as pereopod 4. Pereopod 6 ( Fig. 44G) basis with only one plumose dorsal seta, propodus with distal denticulate spine adjacent to dactylus.

Pleopods ( Fig. 44H) only present on pleonites 1 to 3, biramous, reduced; basis with single dorsal and ventral plumose setae; exopod with outer proximal and three distal plumose setae, endopod with four distal plumose setae, inner margin with three simple setae and proximal plumose seta.

Uropod ( Fig. 44I) biramous, basis with two plumose distal setae; endopod longer than basis, of three segments increasing in length, second segment distally with two setae, third segment twice as long as first with one stout and two more slender distal setae; exopod of one segment, just shorter than proximal endopod segment, with two distal setae.

Description of male. Male closely similar to female, chelipeds not significantly dimorphic, but antennule with main flagellum of six segments. Penial tubercle conspicuous ventrally on pereonite 6.

Etymology. Named after the State of Victoria (and thus indirectly Queen Victoria), off which this species is by far the commonest pagurapseudid.

Remarks. P. inquilinus Bamber 2007 , from 440–450 m depth off New Caledonia, is the only previously-described species of Pagurapseudes to have two segments in the accessory flagellum of the antennule (all others having only one), and shows many similarities to the present species in the morphology of the antennule, antenna and pereopods, but has seven segments in the main flagellum (in both sexes). P. victoriae sp. nov. is also distinguished in having the complex denticulation on the maxilliped basis and palp (absent in P. inquilinus ), and only three setae on the maxillule palp (six in P. inquilinus );conversely, the New Caledonia species has ventral spine-like apophyses rather than simple setae on the basis of the cheliped, and simple spines rather than plumose setae proximally on the cheliped carpus, and is without the dorsal denticulations on the basis of pereopod 1, has fewer lateral but more dorsal plumose setae on the carapace, and the uropod exopod is longer than the proximal endopod segment (shorter in P. victoriae , indeed, notably small for the genus).

The only species of Macrolabrum to have two segments in the accessory flagellum of the antennule are M. aenigmaticus Guţu, 1997 , (from Bali), M. boeri Băcescu 1981 and M. abrucei ( Bãcescu, 1981) comb. nov. (both from the Great Barrier Reef), but those species have only four segments in the main flagellum (the distal segment being comparatively minute in all three), and no complex apophyses on the proximal article of the antennule peduncle (as well as typical Macrolabrum pleopods).

The variation in the numbers of antennular flagella articles, although consistent in their distinction from other species, and the variation in denticulation of the rostrum in the present species are notable, as these characters have been used (albeit not in isolation) in distinguishing between other pagurapseudid species, which are rarely taken in such profusion as was P. victoriae .

Pagurapseudes victoriae was collected throughout the Bass Strait, at depths from 2 to 130 m, on sandy substrata.