Parapseudes blandowskii, 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 : 50-56

Parapseudes blandowskii sp. nov.

Figures 33–36

Material examined. 1 brooding, holotype (J24152), Stn CRUST 153 , Cappers Camp, west end of Nelson Bay, off rock platform, 38º24'S 141º34'E, 5 m depth, 29 February 1992, coll. B.F.Cohen & R. S.Wilson, SCUBA airlift.4, 22 (10 brooding,7 with oostegites), 5 subadults (J57615), 1 (J57795), 1 (J58574), paratypes, Stn CPBS 41 N, Western Port, 38º20.81'S 145º13.85'E, 13 m depth, 30 March 1965, sandy gravel; 2, 8 (6 brooding) (J57634), paratypes, Stn CPBS 23 S, Western Port, 38º21.69'S 145º13.51'E, 11 m depth, 9 March 1965, muddy sand; 1 subadult (J57630), paratype, Stn CPBS 23 N, Western Port , 38º20.29'S 145º14.18'E, 10 m depth, 10 March 1965, sandy gravel; 33 specimens (including and brooding) (J57622), paratypes, Stn CPBS 33 S, Western Port , 38º22.06'S 145º14.10'E, 13 m depth, 5 March 1965, reef with sponges; 3 (2 brooding, 1 with oostegites) (J56359), paratypes, Stn CPBS 41 N, Western Port , 38º20.81'S 145º13.85'E, 13 m depth, 30 March 1965, sandy gravel; 1 (J56199), paratype, Stn CPBS 32 N, Western Port , 38º19.71'S 145º13.82'E, 14 m depth, 25 Agust 1966, sand; 2, 4 (1 brooding) (J57627), paratypes, Stn CPBS 33 S, Western Port , 38º22.06'S 145º14.10'E, 13 m depth, 5 March 1965, reef with sponges; 32 specimens (including and brooding) (J57645), paratypes, Stn CPBS 41 N, Western Port , 38º20.81'S 145º13.85'E, 13 m depth, 30 March 1965, sandy gravel, coll. A.J. Gilmour; 4 (3 brooding), 1 subadult (J56363), paratypes, Red Rock Point Island , sublittoral, 23 July 1974; 1, 1 (J56361), paratypes, Cruise 81-T-1 Stn BSS 185 , Western Bass Strait , 38º48.0'S 143º14.5'E, 47 m depth, 20 November 1981, rocky bottom, coll, R. Wilson; 1, 1 brooding (J56291), paratypes, Western Port sublittoral, 25 November 1971, coll J E Verse, H F Seed .

Description of female. Body ( Fig. 33) typical of the genus, holotype 4.0 mm long (tip of rostrum to posterior of pleotelson), five times as long as wide, narrower posteriorly. Cephalothorax pentangular, as long as wide including rostrum, anterior margin produced into convex, triangular rostrum with smooth anterior margin; lateral indentation anterior to branchial chambers. Eyes present on rounded eyelobes. All pereonites with lateral margins uniformly convex, appearing as posterolateral rounded apophyses on pereonites 3 to 6 owing to anterior (3 and 4) or posterior (5 and 6) lateral indentations, each with two to four conspicuous simple lateral setae; pereonite 1 shortest, about one-quarter as long as cephalothorax; pereonites 2 to 5 progressively longer, pereonite 6 as long as pereonite 3 (all pereonites respectively 3.5, 2.8, 1.7, 1.6, 1.5 and 1.7 times as wide as long). Pleon twice as long as pereonite 5, of five free subequal pleonites, the first four only bearing pleopods, and rectangular pleotelson; pleonites more than four times as wide as long, laterally expanded by spiniform apophyses each bearing two or three simple setae distally, pleonite 1 with dorsal row of setae. Pleotelson distally extended and rounded, half as long as whole pleon, 1.3 times as wide as long, bearing lateral and dorsal simple setae.

Antennule ( Fig. 34A). Peduncle proximal article compact, widest at mid-length, 2.3 times as long as wide, inner margin with row of four simple setae just distal of mid-length and subdistal seta, outer margin with penicillate setae in proximal third and four simple setae in distal two-thirds; second article one-third as long as article 1, 1.5 times as long as wide, with outer and inner subdistal tufts of three simple setae; third article 0.4 times as long as second and wider than long; fourth article just shorter than third, naked. Main flagellum of 10 segments, segments 6 and 8 each bearing single aesthetasc; accessory flagellum of 4 segments.

Antenna ( Fig. 34B). Proximal peduncle article with outer rounded apophysis, naked; article 2 0.8 times as long as article 1, outer margin with one simple marginal seta, linguiform squama with six simple setae around distal margin; peduncle article 3 shorter than wide, one-third as long as article 2, with one distal seta; article 4 as long as article 1, with one distal seta; article 5 one-third as long as article 4, with one distal seta. Flagellum of five segments.

Labrum ( Fig. 34C) rounded, distally finely setulose. Left mandible ( Fig. 34D) bearing strong, crenulated pars incisiva, lacinia mobilis robust with five strong denticulations, setiferous lobe with three trifurcate and one bifurcate setae, pars molaris robust, blunt, margin with anterodistal row of finely denticulate teeth (as shown for right mandible, Fig. 34E); mandibular palp of three articles, proximal article longer than wide with four setae on inner margin, article 2 twice as long as article 1 with two longer and three shorter setae in distal half, article 3 0.8 times as long as article 2 with eight inner finely denticulate setae in distal two-thirds and six longer subdistal to distal curved simple setae. Right mandible ( Fig. 34E) as left but without lacinia mobilis. Maxillule ( Fig. 34F) inner endite with five setulate distal setae, inner and outer margins setulose; outer endite with ten distal spines and two subdistal setae, outer margin finely setulose; palp of two articles, distally with four setae. Maxilla ( Fig. 34G) with sparse fine setae on outer margin; outer lobe of moveable endite with three simple subdistal setae and seven simple distal setae; inner lobe of moveable endite with five simple and seven setulose distal setae, inner margin with three subdistal simple setae; outer lobe of inner endite distally with four outer simple setae, one distally-bilaterally-setulose spine, two mid-distal simple spines, three stout trifurcate spines, and one inner stout spine distally setulose on outer margin, subdistally with one distally-bilaterally-setulose spine; inner lobe of fixed endite with rostral row of 18 setae guarding six longer finely-denticulate setae, inner margin finely denticulate. Labium ( Fig. 34I) with microtrichia along outer margin, palp with fine lateral setules and three simple distal spines. Maxilliped ( Fig. 34H) basis naked; palp article 1 with single fine distal spine on outer margin and three fine simple inner proximal setae; palp article 2 longer than wide, with rows of numerous short setae and two longer simple setae along inner margin, outer margin with four distal setae; palp article 3 as long as wide, with 14 simple setae along inner margin, in two rows; palp article 4 with seven distal setae and one subdistal seta. Endite ( Fig. 34 H') with bilaterally-setulose inner caudodistal seta, distal margin with simple outer setae and inner half bearing slender, distally rugose spines.

Cheliped ( Fig. 35A) slender, basis 2.7 times as long as wide, dorsally naked, ventrally with one subdistal and paired distal fine setae; exopodite present, 3-articled, distal article with four plumose setae. Merus lozenge-shaped, with five ventrodistal simple setae. Carpus 2.6 times as long as wide, with two mid-ventral and two ventrodistal setae. Chela palm (propodus) longer than wide, with ventral submarginal group of three setae, dorsal submarginal row of three shorter setae, comb of four longer setae adjacent to dactylus articulation. Chela fingers shorter than palm, ventral margin of fixed finger with five setae; two setae near inner base of fixed finger; cutting edge with fine spinules and row of eight setae but no apophyses, distal claw slender, curved; dactylus with three subdistal setae, row of stout setae along cutting edge, distal claw pointed.

Pereopod 1 ( Fig. 36A, B) basis 3.7 times as long as wide, dorsally with two proximal spines and adjacent seta, and one subdistal spine, ventrally with proximal and mid-ventral setae, ventrodistally with small spine and tuft or two shorter and three longer setae; exopodite present, 3-articled, distal article with six plumose setae. Ischium with single dorsodistal and tuft of longer ventrodistal setae. Merus half as long as basis, expanded distally, with entire row of ventral simple setae, submarginal spinules, and ventrodistal spine, dorsally with slender, curved dorsodistal spine and long adjacent simple setae almost as long as carpus. Carpus as long as merus, with six or seven ventral spines and intervening simple seta, dorsal margin with numerous simple setae and slender, curved dorsodistal spine. Propodus as long as carpus, with nine ventral spines alternating with simple setae, four ventral submarginal spinules, two distal spinules, simple dorsal setae in proximal half and two dorsodistal spines. Dactylus half as long as propodus, with mid-dorsal fine setae; unguis half length of dactylus.

Pereopod 2 ( Fig. 36C) more slender. Basis 3.7 times as long as wide with small dorsal spine in distal half and ventrodistal tuft of setae mostly twice as long as ischium. Ischium with ventrodistal tuft of setae as long as merus. Merus 0.7 times as long as carpus, with curved dorsodistal spine, row of ventral simple marginal setae and straight ventrodistal spine. Carpus with five ventral spines interspersed with setae, groups of inner mesial and dorsodistal simple setae, and one shorter straight subdistal spine and one longer curved dorsodistal spine. Propodus articulating anaxially on merus, just longer than merus, with five ventral and two dorsodistal spines with interspersed setae. Dactylus curved, with fine mid-dorsal seta, unguis slender, together 0.8 times as long as propodus. Pereopod 3 ( Fig. 36D) similar to pereopod 2, but basis with dorsal seta rather than spine, merus with two ventrodistal spines, carpus with longer marginal and shorter submarginal ventral spines and three dorsodistal spines, propodus with dorsal penicillate seta.

Pereopod 4 ( Fig. 36E) similar to pereopod 3 but basis stouter, twice as long as wide; merus with six ventral and one dorsodistal setae; carpus with numerous ventral and distal setae; propodus with dorsoproximal penicillate seta; dactylus with claw ( Fig. 36 E') half length of adjacent setae, half length of propodus. Pereopod 5 ( Fig. 36F) similar to pereopod 4, but basis with fine dorsoproximal setae; carpus with curved dorsodistal spine, ventral margin densely setose and spinose; dactylus plus unguis 0.8 times as long as propodus. Pereopod 6 ( Fig. 36G) similar to pereopod 5 but basis with plumose setae along entire dorsal and ventral margins, two ventrodistal setae plumose; merus with single long dorsal plumose seta; carpus with three dorsal plumose setae in proximal half; propodus with ventrodistal submarginal row of 30 spinules, fine distal compound spinules, dactylus plus unguis 0.8 times as long as propodus.

Pleopods ( Fig. 36H) in four pairs all alike. Basis elongate, with four dorsal and three ventral plumose setae. Endopod shorter than exopod without proximal articulation; both rami slender, with 12 to 14 marginal plumose setae.

Uropod ( Fig. 35C) biramous; basis with distal crown of about 12 simple and two penicillate setae; exopod 2.75 times as long as basis with seven elongate segments; endopod nearly five times as long as exopod, with about 27 segments.

Distinctions of male. Penial tubercle conspicuous. Flagella of antennule and antenna with numerous aesthetascs.

Cheliped ( Fig. 35B) robust and highly dimorphic; basis 2.4 times as long as wide, dorsally with conspicuous paired tooth-like apophyses in proximal half, ventrally with mid-ventral spine and two fine distal setae; exopodite present, 3-articled, distal article with four plumose setae. Merus stout with ventrodistal shoulder bearing five setae. Carpus as long as wide, with paired mid-dorsal setae, dorsal subdistal tooth-like apophysis, ventroproximal hooked apophysis with three adjacent setae, ventrodistal corner finely rugose with row of five setae. Chela palm (propodus) as long as wide with mid-distal triangular apophysis with tuft of numerous setae; fixed finger distally squared with conspicuous proximal invagination, ventral margin with five longer setae and distal comb of seven shorter setae; cutting edge with small apophyses; dactylus with two larger apophyses on cutting edge, distal claw overreaching fixed finger.

Basis of pereopod 1 ( Fig. 36B) dorsally with two proximal spines and adjacent seta, and one subdistal spine as female.

Etymology. named after Wilhelm Blandowski (1822–1878), a founder of the Geological Society of Victoria, and the first scientist appointed to the then new Victorian Museum, Melbourne, on 1 April 1854.

Remarks: Lang (1965) synonymized all Parapseudes material worldwide into P. latifrons ( Grube, 1864) , with a putative distribution from the Yugoslavian Adriatic (type locality), the Mediterranean, the Atlantic Ocean, the Caribbean, Pacific Central and South America through Hawaii to Japan. His decision was based on observing variation in the number of uropod segments, the number of ventral spines on the distal articles of pereopod 1, and the number of segments in the antennule flagella, all characters on which earlier species had been distinguished. From our present knowledge of sibling species in Tanaidacea , such a synonymy is no longer tenable. Both Guţu (1998a), in his preliminary reassessment of the genus, and Larsen & Shimomura (2008) in their sensible discussion of Parapseudes , point out that the many described species require detailed re-examination in order to determine their validity, and indeed to understand the world-wide diversity of this genus.

Guţu (1998a; 1998b; 2001) distinguished four species in the genus based, inter alia, on the number of dorsal proximal spines on the basis of pereopod 1. To extend this concept, P. latifrons sensu Sars (1882) (Mediterranean), P. algicola ( Shiino, 1952) ( Japan) and P. francispori ( Bãcescu, 1980) (Mediterranean) have one proximal spine, P. latifrons sensu Guţu (1998b) ( Tanzania) and P. latifrons sensu Lang (1965) ( Japan) (both non Rhoëa latifrons Grube, 1864 ) have two proximal spines, and P. inermis ( Silva Brum, 1974) ( Brazil) and P. trispinosus Guţu, 1998 (a) ( Indonesia) have three; none of these have a subdistal spine. P. pedispinis ( Boone, 1923) (California) has one proximal spine and one subdistal spine on the pereopod 1 basis. P. neglectus Miller, 1940 (Hawaii), P. similis Vanhöffen, 1914 ( Cape Verde) and P. spongicola Brown, 1958 ( South Africa) apparently have no such spines, although the original (and only) descriptions of these three species are somewhat wanting. P. arenamans Larsen & Shimomura, 2008 ( Japan) definitely has no such spines.

These last authors suggested that the appearance of such spines may be an artefact based on setae embedded in mucus: this is not the case for the present material, nor for that of P. latifrons agg. sensu Bamber (2005) from S.W. Australia (see below). The spination of the pereopod 1 basis in P. goodei Richardson, 1905 ( Bermuda) and P. hirsutus Stebbing, 1910 (Chagos) is not known.

Parapseudes blandowskii sp. nov. has two proximal spines on the basis preceded by a seta and one subdistal spine dorsally on the basis of pereopod 1. This basis spination most closely resembles that of P. latifrons agg. of Bamber (2005), from Esperance, southwest Australia, (based only on females) which has three proximal and one subdistal basis spines, and of P. pedispinis , redescribed from California by Menzies (1953), although that species has only one proximal spine and is without the adjacent seta. Further, the male cheliped of P. pedispinis (as that of all other described males) is without the dorsal and ventral tooth-like apophyses on the carpus shown by P. blandowskii . The Esperance species, currently being redescribed elsewhere, has a distinctly different dactylus on pereopod 4.

From species where the spination of the pereopod 1 basis is unknown, P. blandowskii differs in the ventral spination of the merus, carpus and propodus of pereopod 1, in the number of segments in the antennule flagella (notwithstanding the variation inferred by Lang, 1965), in the proportions of the pereonites, the plumose setation of pereopod 6, and particularly in the conformation of the male cheliped carpus, inter alia.

Both Larsen & Shimomura (2008) and Guţu (1998a; 1998b) found in their species and in P. francispori (see Guţu, 2001) that the dactylus of pereopod 4 was reduced to a small tubercle-like structure with the unguis reduced to a seta, and both speculated that this might be the norm in the genus. The present species shows a normal (although reduced in size) dactylus plus unguis on pereopod 4 ( Fig. 36E, detail). A normal dactylus and unguis were also shown by Sars (1886) for what must be taken as P. latifrons sensu stricto, and by Shiino (1952) in P. algicola , while that of P. latifrons agg. from Esperance has a reduced but not tubercle-like dactylus and unguis.

Parapseudes blandowskii is only the second Parapseudes species presently known from Australasia, and occurred on sandy substrata at depths of 10 to 15 m in Western Port, occasionally deeper outside that embayment. P. latifrons agg. of Bamber (2005) was found on sandy substrata with rhodoliths and on the red alga Osmundaria prolifera at depths from 18 to 40 m in Esperance Bay, southwest Australia.

Guţu (1998a) gave a revised diagnosis for the genus, but failed to include therein two significant characterizing features, viz the dorsal row of setae on pleonite 1 and the presence of only four pairs of pleopods. This last characteristic is particularly diagnostic for Parapseudes .