Paratya tasmaniensis Riek, 1953

Suter, Phillip J., Mynott, Julia H. & Crump, Megan, 2022, New species of Paratya (Decapoda: Atyidae) from Australian inland waters - linking morphological characters with molecular lineages, Memoirs of Museum Victoria (Mem. Mus. Vic.) 81, pp. 55-122 : 97-101

Paratya tasmaniensis Riek, 1953

Figures 24–26

Paratya tasmaniensis Riek, 1953 (fig. 24a); type examined by MC .

Paratya australiensis Williams and Smith, 1979

Lineage 8 ( Cook et al., 2006)

Lineage B ( McClusky, 2007)

Type Locality: Small stream at Kingston , Tasmania, just above the tidal zone, 10 January 1947 (Browns R) .

Material Examined: Tasmania: Coal R near Campania , − 42.6887 S, 147.4359 E, 11 July 2011 ( PS); George R on Billabong Bay Rd near St Helens, − 41.3137 S, 148.2656 E, 9 July 2011 ( PS); Elizabeth R at Campbelltown , − 41.9332 S, 147.4934 E, 13 July 2011 ( PS); Browns R at Kingston, − 42.9659 S, 147.3117 E, 12 July 2011 ( PS); Swamp off Five Mile Rd , Flinders Island , 39.9053 S, 147.9746 E, 1 November 1973 ( TW, PSL, BK) .

Victoria: Wimmera R downstream of Dimboola Weir ,− 36.4557 S, 142.0167 E, 6 March 2012 (Vic EPA); Glenelg R at Ford Reserve, − 37.2472 S, 141.8458 S, 11 July 2017 ( BM); Hamilton Lake boat ramp, − 37.7327 S, 142.0399 E, 2 February 2018 ( PS); Glenelg R , − 37.9289 S, 141.2782 E, 1 November 2017 ( AC); Glenelg R near Kanagulk , − 37.1497 S, 141.8637 E, 1 November 2017 ( AC) .

New South Wales Stream on Gerrigong Ck Rd, Upper Kangaroo Valley , − 34.6870 S, 150.6000 E, 27 September 2017 ( PS, JM. JH) ; Kangaroo R, Hampden Bridge , − 34.7272 S, 150.5218 E, 27 September 2017 ( PS, JM. JH) ; Maguire Ck , − 28.0837 S, 153.3364 E 26 May 2015 ( BM) ; Hastings R off Oxley Highway , − 31.4647 S, 152.6278 E, 1 November 2011 ( PS, JM, MC) .

South Australia. Brenda Park wetland south of Morgan , − 34.0818 S, 139.6743 E, 8 November 2011 ( CM) .

Diagnosis: P. tasmaniensis differs from all other species by the following combination of characters: rostrum long, extending beyond both antennular peduncle and scaphocerite, dorsal edge straight or very fine curve, dorsally armed with 22–29 spines, 2–4 postorbital spines, ventrally with 4–13 large serrations over a length of 2.10–3.40 mm, all forward of greatest depth; distal half of ventral edge straight; left mandible with 4 teeth separated by smooth notch then 4 short ridges at base of a less distinct apical tooth; right mandible with 4 teeth in a single incisor process with large third tooth; scaphognathite of maxilla 2 truncated and square apically extending to two-thirds length of upper endite; maxilliped 1 with exopod flagellum distinct, well developed and with numerous long setose spines on all margins, over half length of caridean lobe; exopod of maxilliped 2 1.57– 2.50 times longer than endopod, epipodite with long podobranchs extending just to base of third segment of endopodite; maxilliped 3 with medial distal margin of apical segment of endopod with 8–11 broad teeth-like spines, outer margin with 3–9 teeth-like spines, exopod long and narrow, tip over-reaching distal end of basal endopod segment; Pereiopod 1 with short and broad to long and slender chelae, carpus short to long and exopod extending to mid-apex of carpus; pereiopod 2 with exopod extending to mid merus; dactylus of pereiopod 3 with prominent terminal claw and 9–11 strong spines on medial margin, exopod extends to mid merus; dactylus of pereiopod 4 prominent terminal claw and 8–12 spines on medial margin, exopod extends to mid merus; dactylus of pereiopod 5 with prominent terminal claw and very regular comb-like row of 70–85 small spines on medial margin, exopod extends to basal to mid merus.

Carapace length 5.40–7.50 mm.

Rostrum long 5.65–7.10 mm, extending beyond the antennular peduncle and well beyond the scaphocerite (fig. 24a), rostral length 0.88–1.26 times carapace length, shape long and slender, usually straight, pointed; rostral length 6.90–8.50 times greater than width; dorsally armed with 22–29 teeth, ratio of dorsal spines to length is 3.33–4.60, 2–4 postorbital spines (fig. 24a); ventrally with 4–13 large spines over a length of 2.10–3.40 mm, at to anterior to point of greatest width (fig. 24a), distal half of ventral edge straight, ratio of ventral spine length to rostral length is 0.33–0.48 with 2.00–6.50 more dorsal spines than ventral spines; rostral length 1.15–1.69 times length of scaphocerite.

Antenna 1 (fig. 24b) peduncle short 4.04–5.52 mm long, not reaching distal tip of scaphocerite, 0.78–1.31 times scaphocerite length. Stylocerite 2.20–2.84 mm long, length 6.88–12.00 longer than wide, 0.33–0.41 times carapace length, reaching beyond distal border of peduncle segment extending almost to apex or just beyond distal angle process (fig. 24b).

Antenna 2 (fig. 24c) second segment 1.20–1.68 mm long, length 1.88–2.83 times width and 0.23–0.37 times length of scaphocerite. Scaphocerite 4.0– 5.4 mm long, 2.86–4.33 times as long as wide and 0.56–0.85 times carapace length.

Mouthparts. Left mandible (fig. 24d, e) with a blunt apical tooth and 4 short ridges at its base, separated from incisors by part smooth and part ridged U-shaped notch. Incisors with 2 large teeth and 2 slightly smaller robust teeth at base. Spine row with 10 spines, each finely setose. Right mandible (fig. 24f, g) with incisors with 4 large teeth in a single incisor process, with third tooth larger than other 3. Spine row immediately below teeth with 9 spines each finely setose, spine row above molar process. Molar process ridged.

Maxilla 1 (fig. 24h) as for P. australiensis .

Maxilla 2 (fig. 24i) scaphognathite truncated and square apically extending to approximately two-thirds length of upper endite.

Maxilliped 1 (fig. 24j) as for P. australiensis .

Maxilliped 2 (fig. 24k) endopod 0.97–1.17 mm long, exopod long and narrow, length 1.55–2.93 mm, exopod 1.57– 2.50 longer than endopod. Epipodite with long podobranch extending to basal third of third segment of endopodite.

Maxilliped 3 (fig. 25a) endopod 5.41–8.32 mm long, 2.34–3.12 times longer than exopod; with 3 distal segments of similar length; basal segment curved, apical segment with large terminal claw, medial distal margin with 8–11 broad teeth-like spines, largest 1–2 in basal half, outer margin with 1–2 long teeth-like spines; middle segment with 2–3 medial spines and 0–4 spines on outer margin. Exopod long and narrow 2.67–3.33 mm, 0.32–0.43 times length of endopod, extends to base of mid segment.

Thoracic appendages. Pereiopod 1 (fig. 25b) short, 4.87–5.68 mm long, 0.74–0.84 times carapace length. Chelae short and broad to long and slender (fig. 25b), 1.49–1.87 mm long, 2.95– 3.43 times as long as wide, 1.75–2.22 times longer than dactylus, 1.25–1.41 times longer than carpus; palm length 1.60–1.83 longer than palm width, 1.33–1.67 times dactylus length. Carpus short to long, 2.00–2.87 times as long as greatest width, broadening distally, distal margin excavate. Segment ratios 0.45–0.78: 1.25–1.41: 1.00 (1.00–2.67) mm: 1.17–1.80: 0.44– 0.53: 2.51–2.68. Exopod extending to mid-apex of carpus.

Pereiopod 2 (fig. 25c) longer than pereiopod 1, 6.76–8.17 mm long, 0.91–1.29 times carapace length. Chelae long and slender (fig. 25c), 1.47–1.81 mm long, 3.06–3.93 times as long as wide, half to two-thirds length of carpus; palm length 1.80–3.35 longer than palm width, 0.80–1.35 times length of dactylus. Propodus 1.57–2.06 times dactylus length. Carpus long 5.79–7.22 times as long as greatest width, slightly broader distally. Segment ratios 0.31–0.40: 0.59–0.71: 1.00 (2.16–2.81) mm: 0.75–1.15: 0.34– 0.50: 0.90–1.38. Exopod extending to mid merus.

Pereiopod 3 (fig. 25d, e) distinctly longer than pereiopod 2 and more slender, length 8.43–10.05 mm, 1.32–1.71 times carapace length. Dactylus with prominent terminal claw and 9–11 strong spines on medial margin (fig. 25e). Propodus 3.87–4.81 times longer than dactylus, length 11.36–14.17 times longer than wide with 11–18 spines on inner margin and 3 transverse spines apically. Merus with 1 strong spine on medial margin and 1 near ventral distal margin. Segment ratios 0.34–0.46: 1.48–1.77: 1.00 (1.66–2.03) mm: 1.63–2.06: 0.44–0.63: 1.40–1.76. Exopod extends to mid merus.

Pereiopod 4 (fig. 26a, b) similar to pereiopod 3, 8.63–10.47 mm long, 1.29–1.76 times carapace length. Dactylus with prominent terminal claw and 8–12 spines on medial margin (fig. 26b). Propodus 3.78–4.80 times longer than dactylus, length 8.06–15.54 times longer than wide, with 14–19 spines on medial margin, none on outer margin; merus with 1–2 strong spines on medial margin and 1 near ventral distal margin. Segment ratios 0.32–0.43: 1.52–1.77: 1.00 (1.66–2.13) mm: 1.73–2.08: 0.41–0.66: 1.55. Exopod extends to mid merus.

Pereiopod 5 (fig. 26c, d) similar length to pereiopod 4, 8.31–10.03 mm long, 1.15–1.68 times carapace length. Dactylus with prominent terminal claw and very regular, comb-like row of numerous (70–85) small spines on medial margin (fig. 26d). Propodus 3.21–4.54 times longer than dactylus, length 11.80–14.71 times longer than wide with 8–14 long medial teeth and external margin without teeth. Carpus without any large spines near distal margin. Merus 1 strong spine on medial margin and 1 near ventral distal margin. Segment ratios 0.41–0.61: 1.85–2.02: 1.00 (1.59–1.93) mm: 1.45–1.76: 0.53–0.70: 0.99–1.52. Exopod extends to basal to mid third of merus.

Abdomen. Pleopods peduncle of first pleopod short, 0.27–0.37 times length of carapace, 2.00–3.93 times width, exopod 1.11–1.78 times peduncle length, endopod 0.55–0.88 times peduncle length (fig. 26g); second pleopod peduncle short, 0.34–0.42 times length of carapace, 2.25–2.94 times width, exopod 1.11–1.63 times peduncle length, endopod slightly shorter 0.91–1.50 times peduncle length. Length of first peduncle 0.96–1.34 times length of second peduncle.

Telson (fig. 26e, f) length 3.80–4.70 mm, 0.59–0.70 times carapace length and tapering distally, 2.83–3.79 times as long as greatest width. Dorsal surface with 2 pairs of strong submarginal teeth-like spines. Posterior margin convex with 1 pair of teeth-like spines outermost, 6–12 long strong setose spines (fig. 26f).

Uropods approximately equal to telson length.

Males endopod of first pleopod excavated apically with 10–14 short spines on external margin and 16–18 long spines on inner margin (fig. 26h, i).

Comments: P. tasmaniensis was described by Riek (1953) from Browns R at Kingston, Tasmania. It is the only species in Tasmania with a wide distribution on the eastern, southern and northern streams, also on the northern west coast streams and on Flinders Island. It does not occur in lakes of the central plateau, except at Lakes Crescent and Sorrell at an altitude of 800 m ( McClusky, 2007). P. tasmaniensis also occurs on the mainland coastal and inland streams in South Australia, Victoria and New South Wales (fig. 32c). It shares the characteristics of a long straight rostrum extending beyond the scaphocerite with P. spinosa and P. strathbogiensis and the distinguishing characters are given in Table 2.

Walker (1973), in his study of Tasmanian Paratya , described the morphological characteristics of P. tasmaniensis (not including mouthparts) and described the life history from the Coal R and a small wetland at Pawleena.

Figures

Figure 24. Paratya tasmaniensis Riek: a, head region and rostrum; b, antenna 1 peduncle and stylocerite; c, scaphocerite; d, left mandible; e, enlarged incisors; f, right mandible; g, enlarged incisors; h, maxilla 1; i, maxilla 2; j, maxilliped 1; k, maxilliped 2. Scale lines 0.2 mm.

Figure 25. Paratya tasmaniensis Riek: a, maxilliped 3; b, pereiopod 1; c, pereiopod 2; d, pereiopod 3; e, dactylus. Scale lines 0.2 mm.

Figure 26. Paratya tasmaniensis Riek: a, pereiopod 4; b, dactylus 4; c, pereiopod 5; d, dactylus 5; e, telson; f, telson terminal spines; g, pleopod 1 of female; h, pleopod 1 of male; i, endopod 1 of male. Scale lines 0.2 mm.