Paratya australiensis Kemp

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 : 62-65

Paratya australiensis Kemp

Figure 5

Paratya australiensis Kemp (1917) ; primary type material no longer exists

P. australiensis Riek (1953)

P. australiensis Williams and Smith (1979) ; neotype male selected from material named by Riek (1953) AM P28693. Neotype examined byMC

Lineage A ( Baker et al., 2004)

Lineage 1 ( Cook et al., 2006)

Numerous authors referred to P. australiensis in both taxonomic ( Calman, 1926; Kemp, 1917; Roux, 1926; Smith and Williams, 1980; Williams, 1977; Williams and Smith, 1979) and ecological studies ( Baker et al., 2004; Balcombe et al., 2007; Boulton, 2003; Bunn and Hughes, 1997; Chessman and Robinson, 1987; Hancock, 1998; Hancock and Bunn, 1997; Hancock and Bunn, 1999; Hancock et al., 1998; Hart et al., 1991; Hladyz et al., 2012; Hughes et al., 2003; Hughes et al., 1995; Hurwood et al., 2003; Kefford et al., 2004; Marchant et al., 1999; Marchant et al., 1984; Metzeling, 1993; Piola et al., 2008; Reidet al., 2008; Richardson and Humphries, 2010; Smith and Williams, 1980; Walsh and Mitchell, 1995; Williams, 1977), but these ecological studies recognised only a single species from the taxonomic decision by Williams and Smith (1979). Based on current knowledge, these identifications should be revisited.

Material Examined: New South Wales: Neotype male AM P28693 Seven Hills, Sydney: Hawkesbury R at Powells Lane , − 33.569 S, 150.745 E, 9 March 2011 ( SW); Hawkesbury R at North Richmond , − 33.589 S, 150.715 E, 9 March 2011 ( SW); Hawksbury R at Wilberforce , −336018 S, 150.8245 E, 21 April 2011 ( SW) Nepean R at Penrith Weir , − 33.746 S, 150.682 E, 14 April 2011 ( SW); Warragamba R upstream of Nepean R confluence, − 33.8589 S, 150.611 E, 18 April 2011 ( SW); Bedford Ck , Blue Mountains , − 33.75 S, 150.4474 E, May 2011 ( SW) MC32 ; Bungonia Ck at Bungonia , − 34.8528 S, 149.9437 E, no date ( SW), Shoalhaven R at Hillview , − 35.1826 S, 149.9541 E, no date ( SW); Boro Ck at Marlowe upper Shoalhaven R, − 35.3426 S, 149.7386 E, no date ( SW); Hacking R at McKell Ave , − 34.1524 S, 151.0284 E, 5 May 2011 ( SW); South Ck at Richmond Rd , − 33.6775 S, 150.8121 E, 30 May 2011 ( SW).

Williams and Smith (1979) fully illustrated P. australiensis , and these have not been duplicated here. Some comparative characters of the two morphotypes are provided (fig. 5).

Diagnosis: P. australiensis differs from all other species by the following combination of characters: rostrum long, extending beyond antennular peduncle and scaphocerite in Sydney streams, dorsal edge very slightly concave, dorsally armed with 16–28 teeth, 1–3 postorbital spines, ventrally with 4–7 large serrations over a length of 0.60–1.5 mm, distal half of ventral edge more or less straight; left mandible with 4–5 teeth separated by finely ridged notch from a less distinct apical tooth; right mandible with 4 teeth in in 2 separate incisor processes; scaphognathite of maxilla 2 rounded apically almost extending to apex of upper endite; maxilliped 1 with exopod flagellum distinct, well developed and with numerous long setose spines on all margins, approximately four-fifths length of caridean lobe; exopod of maxilliped 2 1.70–2.77 times longer than endopod, epipodite with podobranchs extending just to base of third segment of endopodite; maxilliped 3 with medial distal margin of apical segment of endopod with 9–11 broad teeth-like spines, outer margin with 2–4 broad teeth-like spines plus 2–4 smaller spines, exopod long and narrow, tip over-reaching distal end of basal endopod segment; pereiopod 1 with long carpus and long slender chelae, exopod extending to mid carpus–base of propodus; pereiopod 2 with exopod extending to apex of merus; dactylus of pereiopod 3 with prominent terminal claw and 7–11 strong spines on medial margin, exopod extends to mid merus; dactylus of pereiopod 4 prominent terminal claw and 6–11 spines on medial margin, exopod extends to mid-apical third of merus; dactylus of pereiopod 5 with prominent terminal claw and very regular comb-like row of 55–80 small spines on medial margin, exopod extends to mid merus.

Shoalhaven R morphotype: Rostrum extends beyond peduncle, but not beyond scaphocerite, dorsally armed with 16–17 spines, 0 postorbital spines, ventrally with 2–5 spines over a length of 0.60–1.5 mm.

Carapace: length 4.1–8.0 mm.

Rostrum ( Williams and Smith, 1979; fig. 1a): long, 4.0– 5.6 mm, extending beyond both antennular peduncle and scaphocerite in specimens from the Sydney area (fig. 5a) but slightly shorter and not extending beyond the scaphocerite in specimens from the upper Shoalhaven system (fig. 5f), rostral length 0.62–1.24 times length of carapace, dorsal edge very slightly concave, with slight upwards curve, moderately slender to broad and pointed, rostrum 6.75–9.33 times longer than wide; dorsally armed with 16–25 teeth, ratio of rostral spines to rostral length is 3.15–4.90 with 1–3 post orbital spines in the Sydney morphotype (fig. 5a) or 0 post orbital spines in the Shoalhaven morphotype (fig. 5f); ventrally with 2–6 large serrations over a length of 0.6–1.5 mm all anterior to widest point; distal half of ventral edge more or less straight, ratio of ventral rostral spines length to rostral length = 0.13–0.28 and 3.20–8.00 times more dorsal spines than ventral spines; rostral length 0.92–1.5 times length of scaphocerite.

Antenna 1 ( Williams and Smith, 1979; fig. 1, b, c) peduncle 3.40–4.54 mm long, not quite reaching distal tip of scaphocerite, length 0.90–1.07 times as long as scaphocerite. Stylocerite 1.40–2.80 mm long, length 6.89–13.33 longer than width, 0.33–0.43 times carapace length, reaching beyond distal border of peduncle segment, almost to end of acute process on the lateral distal angle of the first segment (fig. 5f).

Antenna 2 ( Williams and Smith, 1979; fig. 1d) second segment of peduncle 1.00– 1.94 mm long, 0.29–0.44 times length of scaphocerite, 2.53–3.80 times longer than wide. Scaphocerite 3.40–4.72 mm long, 0.60–0.85 times carapace length, 2.76–4.25 times as long as wide.

Mouthparts ( Williams and Smith, 1979; figs 1e–i, 2a–c). Left mandible (fig. 5b, g) with 4–5 teeth separated by finely ridged notch from a less distinct apical tooth; spine row immediately below incisor process of 6–10 rugose spines (lifting spines); spine row above molar process of approximately over 20 sparsely setose spines. Right mandible (fig. 5c, h) with 4 teeth separated into 2 incisor groups of 2 teeth, apical and third teeth largest, teeth 2 and 4 shorter; spine row immediately below teeth with 8–10 spines, each finely setose basally; spine row above molar process. Molar process ridged.

Maxilla palps, with 1 long, setose terminal spine and 1–2 simple sub–terminal ones, inner distal angle may be slightly acute.

Maxilla 2 scaphognathite rounded apically almost extending to apex of upper endite. Palps small, terminal parts narrow with 1–2 setose spines.

Maxilliped 1 palp with broad base, short narrow distal lobe, several long setose spines on distal margins. Exopod flagellum distinct, well developed and with numerous long setose spines on all margins, approximately half to four-fifths the length of the caridean lobe.

Maxilliped 2 endopod length 0.68–1.32 mm; exopod long and narrow, length 1.73–2.80 mm, exopod 1.70–2.77 times longer than endopod. Epipodite with podobranchs extending just to base of third segment of endopodite.

Maxilliped 3 endopod length 3.07–7.54 mm, 1.70–2.77 times longer than exopod; with 3 distal segments of similar length; basal segment curved; apical segment with large terminal claw, medial distal margin with 9–11 broad teeth-like spines, largest in basal third, outer margin with 2–4 broad teeth-like spines and 2–4 smaller spines, longest in basal third. Exopod long and narrow, length 1.80–3.62 mm, tip over-reaching distal end of basal endopod segment.

Thoracic appendages ( Williams and Smith, 1979; figs 2d, e, 3a–c). Pereiopod 1 (fig. 5d, i). 3.45–5.49 mm long, 0.68–0.91 times length of carapace. Chelae short to long and slender, 1.09–1.93 mm long, propodus 2.55–3.46 times as long as wide, 1.88–2.21 times longer than dactylus; palm length 1.58–1.91 times width and 1.00–1.38 times dactylus length (fig. 5d, i). Carpus long, 1.47–3.08 times longer than greatest width. Segment ratios compared with carpus length 0.54–0.78: 1.04–1.71: 1.00 (0.92–1.36) mm: 0.99–1.45: 0.35–0.84: 2.21–3.27. Exopod extending to mid carpus–base of propodus.

Pereiopod 2 (fig. 5e, j). length 5.04–9.58 mm, 1.00–1.47 times carapace length. Chelae long and slender 1.11–1.76 mm long, approximately two-thirds carpus length, 3.59–4.14 times as long as wide, palm length 1.71–1.98 times width and 0.82– 1.31 times dactylus length (fig. 5e, j). Propodus length 1.61– 2.07 times longer than dactylus. Carpus 5.76–8.16 times as long as greatest width, slightly broader distally, distal margin with small excavation. Segment ratios 0.30–0.38: 0.56–0.72: 1.00 (1.73–2.84) mm: 0.58–0.96: 0.34–1.00: 0.83–1.49. Exopod extending to apex of merus.

Pereiopod 3 slightly longer than pereiopod 2 and more slender, length 5.7–10.08 mm, 1.19–1.60 times carapace length. Dactylus with prominent terminal claw and 7–11 strong spines on medial margin. Propodus length 3.23–4.56 times longer than dactylus, length 9.81–14.3 times as long as wide with 12–15 spines on inner margin. Merus with 1 strong spine on medial margin and 1 near ventral distal margin. Segment ratios 0.38–0.54: 1.62–1.79: 1.00 (1.07–1.88) mm: 1.60–2.11: 0.50–0.77: 1.60–1.74. Exopod extends to mid merus.

Pereiopod 4 similar to pereiopod 3, 6.09–9.60 mm long, 1.20–1.52 times carapace length. Dactylus with prominent terminal claw and 6–11 spines on medial margin. Propodus length 3.92–4.94 times longer than dactylus, length 10.74– 16.50 longer than wide, with 11–17 spines on medial margin; merus with 1 or 2 strong spines on medial margin and 1 near ventral distal margin. Segment ratios 0.37–0.44: 1.67–1.90): 1.00 (1.16–1.80) mm: 1.64–2.01: 0.54–0.82: 1.18–1.87. Exopod extends to mid-apical third of merus.

Pereiopod 5 similar length to pereiopods 3 and 4, 5.85–9.79 mm long, 1.21–1.57 times carapace length. Dactylus with prominent terminal claw and very regular comb-like row of 55–80 small spines on medial margin. Propodus length 2.83– 3.60 times longer than dactylus, length 9.57–16.54 times longer than wide with 8–16 medial teeth. Carpus approximately half propodus length with 1 large spine near distal margin. Merus with 1 strong medial spine and 0–1 distal spines; ischium less than half length of propodus; segment ratios 0.52–0.74: 1.83– 2.09: 1.00 (1.15–1.85) mm: 1.33–1.90: 0.58–0.99: 1.22–1.69. Exopod extends to mid merus.

Abdomen ( Williams and Smith, 1979; figs 3d–f, 4a–c). Pleopods peduncle of first pleopod short, 0.23–0.33 times length of carapace, 2.62–3.33 times width, exopod 1.05–1.6 times peduncle length, endopod 0.42–0.83 times peduncle length; second pleopod peduncle short, 0.29–0.44 times length of carapace, 2.31–3.5 times width, exopod 1.00–1.58 times peduncle length, endopod slightly shorter 1.00–1.55 times peduncle length. Length of first peduncle 0.93–1.38 times length of second peduncle length.

Telson length 3.00– 4.48 mm, 0.55–0.73 times carapace length, 2.35–3.28 times as long as greatest width, and tapering distally. Dorsal surface with 2 pairs of strong submarginal teeth-like spines. Posterior margin convex with 1 pair of teeth-like spines outermost, 6 long, strong setose spines, and 2 short, simple spines.

Uropods approximately equal to telson length.

Males ( Williams and Smith, 1979; fig. 3d–f). Smaller than females, carapace length 5.25 mm; endopod of pleopod 1 strongly excavated with 12 short external spines on medial margin and 17 long setae on inner margin.

Comments: Lineage 1 specimens are consistent with the neotype of P. australiensis described and illustrated by Williams and Smith (1979) from Seven Hills near Sydney. Kemp (1917) described Paratya australiensis from Clyde, Sydney, but, as the type was missing, Williams and Smith (1979) attempted to find material from the type locality, but were unsuccessful. They selected a specimen from Riek’s (1953) collection from the Seven Hills site as the neotype. Both locations (Seven Hills and Clyde) are in the Parramatta R system and are only 10 km apart ( Williams and Smith, 1979). The material examined in this study was from adjacent catchments. P. australiensis appears restricted to coastal catchments in the Sydney area and in the Shoalhaven catchment. P. australiensis does not have an overlapping distribution with P. walkeri , P. spinosa , P. strathbogiensis and P. gariwerdensis but it does overlap with P. arrostra , P. williamsi , P. whitemae and P. tasmaniensis . P. whitemae has been found at the same locality as P. australiensis , and both occur in the Hawksbury R and Nepean R.

P. australiensis can be clearly distinguished from the species possessing a short rostrum ( P. arrostra and P. rouxi ) by the rostrum extending beyond the peduncle compared with the rostrum that does not extend beyond the peduncle, and characters listed in Table 2.

P. australiensis can be distinguished from all the long rostrum species by the combination of characters listed in Table 3. Main characters include the number of dorsal rostral spines; the number of ventral rostral spine; palm length to width of second cheliped; carpus of pereiopod 1 long; the length of the lower rostral spine row; number of long terminal spines of telson; scaphognathite of maxilla 2 long almost extending to end of endite; right mandible with 2 pairs of incisors ( Table 3). The presence of two morphotypes of P. australiensis is similar to the observations made on another Australian atyid shrimp, Australatya , by Choy et al. (2019).

Figures

Figure 5. Paratya australiensis: a–e, P. australiensis Kemp; f–j, P. australiensis Shoalhaven morphotype; a, rostrum; b, left mandible incisors; c, right mandible incisors; d, first pereiopod; e, second pereiopod; f, rostrum; g, left mandible incisors; h, right mandible incisors; i, first pereiopod; j, second pereiopod. Scale lines 0.2 mm.