Typhlotanais herthio, 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 : 162-166

Typhlotanais herthio sp. nov.

Figures 108–110

Material examined. 1 (J58514), holotype, Eastern Bass Strait, 60 km E of North Point, Flinders Island, Stn BSS 32 , 39º41.7'S 148º39.5'E, 115 m depth, muddy sand, 27 March 1979; coll. G.C.B. Poore; 45 and neuters (J58515) , paratypes, Central Bass Strait, 32 km SE of Cape Otway, Stn BSS 48 DN, 39º01'S 143º49'E, 81 m depth, coarse sand, 07 October 1980; coll. G.C.B. Poore; 41 and neuters (J58518) , paratypes, Central Bass Strait, 66 km S of Rodondo Island, Stn BSS 158 S, 39º48.6'S 146º18.8'E, 82 m depth, sand with silt and mud, 13 November 1981; coll. R. S. Wilson .

Description of female. Body ( Fig. 108A, B) slender, holotype 2.7 mm long, 6.4 times as long as wide. Cephalothorax subrectangular, tapering towards anterior with slight triangular rostrum, 1.2 times as long as wide, about as long as pereonites 1 and 2 together, naked, eyes absent. Pereonite margins parallel, pereonite 1 shortest, 0.4 times as long as cephalothorax; pereonites 2 to 5 subequal, 0.8 times as long as cephalothorax, pereonite 6 shorter, 0.6 times as long as pereonite 5 (all pereonites respectively 2.4, 1.4, 1.4, 1.3, 1.4 and 1.7 times as wide as long). Pleon with five free subequal pleonites bearing pleopods; each pleonite 5.8 times as wide as long. Pleotelson pentangular, one-third length of pleon and twice as wide as long, with four small distal setae ( Fig. 110I).

Antennule ( Fig. 109A) of three articles, proximal article 5.2 times as long as wide, 1.8 times as long as distal two articles together, with row of three strong inner-dorsal setae, outer margin with tufts of one simple and two or three penicillate setae at mid-length and distally; second article nearly twice as long as wide, 0.4 times as long as third article, with single inner distal penicillate and longer simple setae; third article tapering, 0.4 times as long as first article, with five simple and one penicillate distal setae.

Antenna ( Fig. 109B) of six articles, proximal article compact, naked; second article stout, as long as wide, with dorsodistal seta longer than article; third article shorter than wide, with fine dorsodistal seta; fourth article longest, ten times as long as wide, curved, with one simple and one penicillate distal setae; fifth article one-quarter as long as fourth with one distal seta; sixth article minute with four distal setae.

Labrum ( Fig. 109C) rounded, hood-shaped, distally setose. Left mandible ( Fig. 109D) with subtriangular pars incisiva and wide, crenulate lacinia mobilis, right mandible ( Fig. 109E) without lacinia mobilis; pars molaris of both mandibles with strong, rounded tooth-like protrusions around distal margin. Labium ( Fig. 109H) simple, finely setose on outer margins. Maxillule ( Fig. 109F) with eight distal spines, palp ( Fig. 109 F') with two distal setae. Maxilla ( Fig. 109G) ovoid, naked. Maxilliped palp ( Fig. 109I) first article naked, second article with one outer and three inner setae, distal of these finely denticulate in distal half; third article with four inner setae in distal half of article, two of these finely denticulate in distal half; fourth article with five inner to distal setae, four of these finely denticulate in distal half, and one outer subdistal seta; basis with single, long seta reaching distal margin of endites; endites distally with two setae and two slight tubercles, outer distal margin slightly denticulate. Epignath ( Fig. 109J) elongate, linguiform, naked.

Cheliped( Fig.110A)with rounded basis reaching pereonite 1 ventrally, 1.2 times as long as wide, with single dorsodistal seta; merus subtriangular with single ventral seta; carpus elongate, three times as long as wide, with two midventral setae of markedly unequal length, one fine ventrodistal seta, and row of eight setae along dorsal margin; propodus slender, curved, twice as long as wide, fixed finger 0.73 times as long as palm, with two ventral setae, three setae on cutting edge; dactylus with fine proximal seta.

Pereopod 1 ( Fig. 110B) longer than others, coxal apophysis large, triangular, pointed, with seta; basis arcuate, slender, nearly six times as long as wide, with six simple setae along dorsal margin; ischium compact, with ventral seta two-thirds as long as merus; merus 0.4 times as long as basis, with three simple distal setae; carpus just shorter than merus with distal crown of eight simple setae; propodus 1.5 times as long as carpus, with three dorsal subdistal setae, longer ventral subdistal seta; short, stout dactylus with proximal seta longer than dactylus, slender unguis 2.6 times as long as dactylus, both together 0.9 times as long as propodus. Pereopod 2 ( Fig. 110C), coxa similar to that of pereopod 1, basis 3.3 times as long as wide, with midventral seta and eight setae along dorsal margin; ischium with seta only half as long as merus; merus 0.25 times as long as basis, with single dorsal and two ventral distal simple setae, and dense field of microtrichia across ventral and ventrolateral surfaces in distal two-thirds; carpus 1.4 times as long as merus, with distal crown of eight setae and dense field of microtrichia across ventral and ventrolateral surfaces in distal two-thirds; propodus 1.6 times as long as carpus, with two dorsal subdistal setae, longer ventral subdistal seta, and fields of microtrichia; short, stout dactylus with proximal seta longer than dactylus, slender unguis longer than dactylus, both together 0.4 times as long as propodus. Pereopod 3 compact ( Fig. 110D), similar to pereopod 2, basis with six dorsal marginal setae; merus with three ventrodistal setae.

Pereopod 4 ( Fig. 110E) basis stout, 2.1 times as long as wide, with simple mid-dorsal seta and two penicillate setae near ventrodistal corner; ischium with two ventrodistal setae; merus 0.8 times as long as carpus, with field of microtrichia across ventral and ventrolateral surfaces in distal two-thirds, and two small ventrodistal spines; carpus with robust distal molar spine, two simple mid-dorsal and one dorsodistal setae, and “prickly tubercle” ( sensu Błażewicz-Paszkowycz, 2007 ) surrounded by minute spines in ventrodistal half; propodus 1.5 times as long as carpus, with fields of microtrichia, mid-dorsal penicillate seta, strong dorsodistal seta, and two ventrodistal dentiform spines; dactylus slender, with fields of microtrichia, three times as long as curved unguis, both together longer than propodus. Pereopod 5 ( Fig. 110F) as pereopod 4, but carpus with mid-dorsal and dorsodistal spines. Pereopod 6 ( Fig. 110G) as pereopod 5, but basis without penicillate setae, propodus with three dorsodistal setae.

Pleopods ( Fig. 110H) all alike, with naked basis, exopod shorter than endopod; endopod and exopod without setae on inner margin, outer margins with respectively 15 and 21 plumose setae, proximal seta on both rami separated from others.

Uropod ( Fig. 110I) biramous, basis naked; exopod and endopod of one segment, exopod shorter than endopod, with one fine proximal, one slender and one stouter distal setae; endopod with four slender, one stouter and one penicillate distal setae.

Male. Unknown.

Etymology. From the Anglo-Saxon haer – hairy, and thioh – the thigh, alluding to the density of dorsal marginal setae on the bases of the anterior pereopods, which distinguish this species most evidently from the other species of the greenwichensis - group of Typhlotanais sensu lato; noun in apposition

Remarks. With the pronounced coxal spurs on the anterior pereopods, the curving carpus-propodus and the dorsal marginal spines on the carpus of the cheliped, and the prickly tubercles on the posterior carpi, this species fits into the “ greenwichensis -group” of Błażewicz-Paszkowycz (2007). The two described species of this group are T. greenwichensis Shiino, 1970 , from the Antarctic-Subantarctic, and T. messinensis Sars, 1882 from the Mediterranean.

Typhlotanais greenwichensis differs from T. herthio sp. nov. in being more elongate (nearly seven times as long as wide), with a less-slender proximal article to the antennule (four times as long as wide), and, most obviously, has only a few dorsal marginal setae on the pereopods 1 to 3 (4, 4 and 3 respectively). T. messinensis is quite distinct in having a more compact proximal peduncle article to the antennule (three times as long as wide), and two-segmented rami on the uropods.

Typhlotanais herthio was collected sporadically through the Bass Strait, from sandy substrata at depths between 81 and 115 m.