Saltipedis floccus, 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 : 56-62

Saltipedis floccus sp. nov.

Figures 38–40

Material examined. 1 brooding (J55832), holotype, Stn BSS159 , Central Bass Strait , 39º43.5'S 146º18.8'E, 80 m depth, 13 November 1981, muddy shell, coll. R. Wilson; 1 (J57600) , paratype, Stn BSS155 , Central Bass Strait , 38º55.5'S 145º17.0'E, 70 m depth, 12 November 1981, fine sand, coll. R. Wilson. 2 (J57731) , paratypes, Stn BSS117 , Central Bass Strait , 40º38.0'S 145º23'E, 36 m depth, 4 November 1980, muddy shell with grit, coll. M. Gomon & G C B Poore. 1 (J57721), paratype, Stn BSS68 , Western Bass Strait , 39º27'S 142º55'E, 180 m depth, 10 October 1980, coarse sand, carbonate, coll. G C B Poore. 1, 6 subadults (J57718), paratypes, Stn BSS 133 T, Central Bass Strait , 30 km N of Wynyard, Tasmania, 40º33.07'S 145º44.68'E to 40º36.22'S 145º48.68'E, 68 m depth, mud, 04 February 1981, coll. M.F. Gomon et al., 20 m otter trawl. 3 (J57737), paratypes, Stn BSS 158 , Central Bass Strait , 66 km S of Rodondo Island, Victoria, 39º48.36'S 146º18.48'E, 82 m depth, sand with silt and mud, 13 November 1981, coll. R. S. Wilson. 1 (J57725) , paratype, Stn BSS158 , Central Bass Strait , 39º49.5'S 146º18.5'E, 82 m depth, 13 November 1981, sand-silt-mud, coll. R. Wilson. 1 (J57725) , paratype, Stn BSS158 , Central Bass Strait , 39º49.5'S 146º18.5'E, 82 m depth, 13 November 1981, sand-silt-mud, coll. R. Wilson. 1 without cephalothorax (J55850) , paratype, Stn WBES 1746 , Western Port , 38º29.47'S 145º06.17'E, 79 m depth, 25 November 1974, Smith-McIntyre grab, coll. N.Coleman. 1 (J55864), paratype, Stn HP BES 1747/2, Western Port , Victoria, 38º27.32'S 145º08.35'E, 18 m depth, 25 November 1974, Smith-McIntyre grab, coll. N. Coleman. 1 (J55900), paratype, Stn CPBS 100 , Western Port , 38º21.15'S 145º13.23'E, 4 m depth, 24 March 1965, mud and Zostera ; 2 (J57663) , paratype, Stn CPBS 01 S, Western Port , 38º21.73'S 145º13.23'E, 3 m depth, 1 April 1965. 1 (J17162),1 (J46538) , paratypes, Stn MSL EG6, Eastern Bass Strait , 19 km S of Lakes Entrance, Victoria, 38º04'S 148º00'E, 92 m depth, 12 August 1989, Smith-McIntyre grab, coll. G.D. Parry.

Description of female. Body ( Fig. 38A) dorsoventrally flattened, holotype 9.2 mm long (tip of rostrum to posterior of pleotelson), five times as long as wide, tapering towards posterior. Cephalothorax subrectangular, as long as wide, with pronounced triangular rostrum; eyelobes distinct, dark ocelli present. Spine-like hyposphenium present mid-ventrally between chelipeds, but no hyposphenium on pereonite 2. Pereonites 1 to 3 with tufts of four to six anterolateral setae, pereonites 4 to 6 with setae dispersed along lateral margins; pereonites 1 and 2 subequal, shortest, about one-third as long as cephalothorax, pereonite 3 1.2 times as long as pereonite 2; pereonites 4 and 6 subequal, 1.7 times length of pereonite 2; pereonite 5 longest, 2.3 times as long as pereonite 2 (all pereonites respectively 3.3, 3.2, 2.6, 1.8, 1.2 and 1.4 times as wide as long). Pleon one-quarter as long as whole body, with five free, pleonites bearing pleopods and backwardly-directed hyposphenia ( Fig. 38 C'); pleonite 1 with row of setae around anterior margin, posterior pleonites naked; pleonites 4.7 times as wide as long. Pleotelson ( Fig. 1B) rectangular, more than half-length of pleon, twice as long as wide, with sparse lateral setae.

Antennule: only basal peduncle articles present on any specimen ( Fig. 39A); proximal peduncle article 1.7 times as long as wide, inner margin with row of five setae at mid-length and distal tuft of 7 or 8 setae, outer margin with four groups of setae, a proximal row of penicillate setae, a subproximal tuft of simple and penicillate setae, a subdistal row of simple setae and a distal tuft of six simple setae. Second article 1.5 times as long as wide, 0.5 times length of first, with simple inner distal setae, simple outer proximal setae and an outer distal tuft of simple and penicillate setae.

Antenna ( Fig. 39B) with proximal peduncle article expanded on inner margin as a rounded apophysis with three spinules. Article 2 as long as first, with four simple setae adjacent to elongate squama bearing seventeen marginal setae. Peduncle article 3 shorter than wide with inner seta. Fourth article just longer than third, as long as wide, with two inner setae; fifth article twice as long as third, with long inner seta. Flagellum of thirteen segments, mostly with setae longer than two flagellar segments.

Epistome conspicuous ( Fig. 38C). Labrum rounded, distally setulose.Right mandible ( Fig.39C) with three rounded “teeth” on pars incisiva; setiferous lobe with four trifurcate and one simple setae; left mandible ( Fig. 39D) as right but with dentate lacinia mobilis, and six trifurcate setae on setiferous lobe; pars molaris ( Fig. 39 D') stout, blunt with distal rugosity; palp ( Fig. 39D ") of three articles, proximal article with field of twelve inner setae; second article twice as long as first with three shorter and one longer simple inner setae at mid-length; third article as long as first, with eleven shorter inner subdistal setae, two longer distal setae and three shorter submarginal dorsal setae. Labium ( Fig. 39G) with outer rows of microtrichia, inner distal margin finely setose, palp with inner fine lateral setules, three simple distal setae, outer proximal microtrichia and small, rounded, setose inner apophysis. Maxillule ( Fig. 39E) inner endite with outer apophysis, and four compound distal setae; outer endite with twelve distal spines and two subdistal setae, inner and outer margins finely setose; palp of two articles, distally with six graduated setae. Maxilla ( Fig. 39F) typical of genus, outer margin denticulate, moveable endite outer lobe with two subdistal and five distal finely denticulate setae, inner lobe with twelve plumose/denticulate setae; fixed endite outer lobe with simple, trifurcate, plumose and bilaterally denticulate distal spines, inner lobe with nine longer plumose setae and rostral row of 37 setae. Maxilliped ( Fig. 39H) with simple setae; basis with inner and outer simple setae and outer distal spine-like apophysis; first palp article with paired inner and outer setae and outer distal spine-like apophysis; second palp article with inner margin bearing numerous setae largely in two rows, longest two inner setae exceeding fourth article, and tuft of nine outer distal setae; third palp article with about 13 recurved inner setae; fourth palp article with seven setae around distal margin and one outer subdistal seta. Endite ( Fig. 39 H') distal margin with outer simple setae, central rod-pike setae and inner blunt spines, inner margin with plumose setae and four coupling hooks. Epignath ( Fig. 39I) large, cup-shaped, with setose outer margin and finely plumose distal spine.

Cheliped ( Fig. 40A) slender. Basis 2.7 times as long as wide, with mid-ventral spine and two subdistal penicillate setae; dorsally naked. Exopodite 3-articled; article naked, article 3 with four plumose setae. Merus subrectangular, with ventroproximal, mesial and ventrodistal groups of setae. Carpus very slender, four times as long as wide, two simple setae along ventral margin, five setae along inner midline, and tufts of shorter dorsodistal and ventrodistal setae. Chela slender, palm (propodus) 1.2 times as long as wide with numerous setae on inner face; ventral margin setose along fixed finger; cutting edge of fixed finger without apophyses but with small curved setae. Dactylus longer than palm, with no apophyses on cutting edge.

Pereopod 1 ( Fig. 40B) basis 2.35 times as long as wide, with small ventral spinules, ventrodistal spine and long ventrodistal setae exceeding distal margin of ischium, dorsal margin with four setae in proximal half. Exopodite conspicuous, 3-articled, article 2 with one seta, article 3 with five plumose setae. Ischium with three ventrodistal setae. Merus wider distally, with slender dorsodistal spine and shorter, stouter ventrodistal spine, tufts of simple setae ventrally, mesially and dorsodistally. Carpus compact, as long as merus, with two elongate dorsodistal spines, two shorter ventrodistal spines, setae along entire dorsal margin, dorsodistal, ventral and ventrodistal tufts of setae. Propodus as long as carpus, with six ventral spines increasing in length towards distal margin interspersed with setae, two dorsodistal slender spines and row of setae along dorsal margin, mesial field of sparse setules. Dactylus stout, with two ventral denticulations and dorsal seta, unguis distinct, pointed, both together 0.8 times as long as propodus.

Pereopod 2 ( Fig. 40C) basis 1.6 times as long as wide, with three ventral spinules, and tuft of long ventrodistal setae exceeding distal margin of ischium. Ischium shorter than wide with tuft of seven ventrodistal setae; merus shorter than carpus, with dense field of ventral setae, two ventrodistal slender spines, dorsal margin naked. Carpus with diagonal row of setae along inner face, two dorsodistal slender spines, ventral margin with five fine spines interspersed with setae; propodus just longer than carpus, ventrodistal margin with five fine spines interspersed with setae, dorsally with three fine spines interspersed with setae. Dactylus compact, unguis shorter, distinct, both together 0.6 times as long as propodus.

Pereopod 3 ( Fig. 40D) similar to pereopod 2, but basis armed only with one mid-ventral and three dorsoproximal penicillate setae.

Pereopod 4 ( Fig. 40E) basis slender, with sparse ventral spinules and tuft of ventrodistal setae. Ischium with ventrodistal row of six setae. Merus with numerous ventral setae and one ventrodistal slender spine. Carpus 1.3 times as long as merus, ventrally with five fine spines interspersed with long setae, diagonal row of setae along inner face distally including five fine spines. Propodus just longer than carpus, with dorsoproximal penicillate seta, ventrally with five fine spines interspersed with long setae, diagonal row of setae along inner face distally including two fine spines; dactylus and claw elongate, 0.75 times as long as propodus.

Pereopod 5 ( Fig. 40F) basis stouter with single ventrodistal seta, ischium with slender dorsodistal spine, spines on merus, carpus and propodus longer than those on pereopod 4, distal propodal spines finely denticulate.

Pereopod 6 ( Fig. 40G) similar to pereopod 5 but basis without complete dorsal marginal row of plumose setae, five ventral plumose setae in distal half; ischium with two dorsodistal spines; propodus ventral and distal margin with row of some 26 small leaf-like spines.

Pleopods ( Fig. 40H) all alike. Basis with five ventral (inner) plumose setae and six dorsal (outer) plumose setae; rami linguiform. Endopod longer than exopod, respectively with 24 and 22 marginal plumose setae.

Uropod ( Fig. 40I) biramous. Basis with two tufts each of four distal setae. Exopod five times as long as basis and of about ten poorly-distinguished segments; endopod damaged on all specimens, but at least twice as long as exopod.

Description of male. Only one male found ( Fig. 38B), with damaged antennae and antennules, without chelipeds. Body similar to that of female, but pereonites 4 and 5 proportionately shorter; cephalothorax with three lateral setae posterior to each eyelobe; all pereonites and pleonites with more dorsal setae.

Etymology. From the Latin, floccus , a tuft or lock of hair, with reference to the distinctive tufts of setae on the lateral margins of the pereonites.

Remarks. Saltipedis floccus sp. nov. is the fourth species of the genus to be described from Australian waters after S. forex , S. incognita Bamber, 2005 (both from southwestern Australia), and S. nugoris from the Bass Strait (see above). All four are generally similar in their habitus (as are all species of the genus other than S. achondroplasia Bamber, Bird & Angsupanich, 2003 ), and they share the unusual feature, not found in any other species of the genus, of outer spine-like apophyses on the maxilliped basis and palp-article-1. They are, however, readily distinguished: S, nugoris and S. forex are without an epistome, and have a triangular or blunt rostrum respectively, while S. floccus and S. incognita have a conspicuous epistome and a pointed rostrum, but no hyposphenia on pereonites 1 or 2 (present in S, nugoris ); S. forex is the only one of these species without a cephalothoracic hyposphenium between the chelipeds, or a dorsodistal spine on the merus of pereopod 1.

S. forex is notably different from the other Australian species owing to the tufts of setae on the lateral margins of its pereonites; the mouthparts are also much more densely setose (notably the mandibular and maxilliped palps), and the present species is the only one to have ventral (as well as dorsal) plumose setae on the basis of pereopod 6.

Despite all of these differences, the four Australian species do broadly seem to be closely related. Guţu (2008b) moved the previously-described three species into a separate genus, Magniaculeus , simply on the feature of the spine-like maxilliped apophyses, ignoring the numerous features by which they differ. In fact, the present species disagrees with a number of the diagnostic characters of Magniaculeus (many of which were vague or not distinct to the newly-described genus), e.g. the labial palp is not ovate, and the propodus of pereopod 1 is not longer than the carpus. Both features are in fact more like that of another genus – Brachylicoa – which Guţu (2006) also somewhat tenuously separated from Saltipedis . Equally, the fine spines on the basis of pereopod 1 in S, nugoris and S. forex are diagnostic features of another of Guţu’s (2006) new genera derived from Saltipedis , Podictenius . Until a more comprehensive and rational analysis of the genus Saltipedis (including Brachylicoa , Magniaculeus and Podictenius ) is undertaken, separating these four species into a separate genus is premature.

Saltipedis floccus was collected throughout the Bass Strait, at depths between 3 and 180 m, normally on heterogeneous substrata, and it was often sympatric with S, nugoris .