Paratya arrostra (Riek), 1953, 2022

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 : 76-82

Paratya arrostra (Riek), 1953 comb. nov.

Figures 12–14

Paratya australiensis arrostra Riek, 1953 ; in part = rostrum mid length (fig. 12a)

Terrors Ck, Dayboro , Queensland. Types examined by MC .

Paratya atacta Riek 1953 ; in part = rostrum very long, comb.Nov. (fig. 12c)

Upper Nerang R, southern Queensland

Paratya atacta adynata Riek 1953 ; in part = rostrum mid length, comb.Nov.(fig. 12b). Small creek in upper reaches of Middle Harbour, Sydney, New South Wales

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

Paratya australiensis Gan et al. (2016) ; determination of the mitogenome of Paratya australiensis .

Lineage 4 ( Cook et al., 2006)

Lineage C ( McClusky, 2007)

Material Examined: Victoria: Hughes Ck at Hughes Ck Rd , − 37.0075 S, 145.3212 E, 28 September 2011 ( PS, JM, MC); King Parrot Ck at Flowerdale, − 37.2953 S, 145.2905 E, 28 September 2011 ( PS, JM, MC); Goulburn R past Loch Gary at flood markers, − 36.2411 S, 145.2866 E, 28 September 2011 ( JM, MC); Yea R at Glenburn , − 37.4239 S, 145.4210 E, 28 September ( PS, JM, MC); Wimmera R downstream of Dimboola Weir , − 36.4557 S, 142.0167 E, 6 March 2012 (Vic EPA); Ovens R near Wangaratta , − 36.3371 S, 146.3191 E, August 2010 ( JM, MC, JM) .

New South Wales : Wakool Reserve , − 35.4963 S, 144.4541 E, June 2011 ( JC); Bagnall’s Lagoon, Albury, − 36.070 S, 146.854 E, April 2011 ( PS); Murray R below Lake Hume , − 36.0998 S, 147.0228 E, 12 August 2010 ( JW, MC, JM); Hawksbury R at Windsor Bridge , − 33.6023 S, 150.8233 E, 10 November 2011 ( SW); Hawksbury R at Wilberforce , − 33.6020 S, 150.8241 E, 10 September 2011 ( SW); Hawksbury R at Sackville Ferry , − 33.5003 S, 150.8746 E, 19 September 2020 ( SW); Hawksbury R North Richmond , − 33.5684 S, 150.7485 E, 9 March 2011 ( SW); South Ck Richmond Rd, − 33.6775 S, 150.8121 E, 30 March 2011 ( SW); McCarrs Ck, − 33.6410 S, 151.2780 E, 13 September 2011 ( SW); Nepean R at Sharpes Weir , − 34.0384 S, 150.6793 E, 15 September 2011 ( SW); Nepean R at Grove Rd , − 34.0415 S, 150.6964 E, 2 April 2011 ( SW); Nepean R at Wallacia Bridge , − 33.8655 S, 150.6374 E, 18 April 2011 ( SW); Nepean R at Maldon Weir , − 34.2034 S, 150.6301 E, 5 April 2011 ( SW); Lachlan R , Newell Highway at Forbes , − 33.3956 S, 147.9903 E, 3 November 2011 ( PS, JM, MC); Lachlan at Cargellico − 32.2033 S, 146.3589 E, Jun 1999 ( PS, TC); Lachlan R at Glenmore , − 33.4413 S, 145.5377 S, July 1999, ( PS, TC); Lachlan R at Goolagong , − 33.6060 S, 148.4324 E, July 1999 ( PS, TC); Lachlan R at Condobolin , − 33.0915 S, 147.1476 E, July 1999 ( PS, TC); Macquarie R at Dubbo , − 32.2470 S, 148.5990 E, 23 September 2010 ( PS, MC); Murrumbidgee R at Wagga Wagga ; − 35.1041 S, 147.3751 E, 11 November 2003 ( PS); Billabong Ck at Coree, − 35.3556 S, 145.5041 E, 24 June 2001 ( PS, LS); Billabong Ck at Moulamein , − 35.0913 S, 144.0334 E, 2 April 2001 ( PS, LS); Billabong Ck at Urana , − 35.3598 S, 146.0942 E, 14 May 2001 ( PS, LS); Billabong Ck at Walbundrie , − 35.6971 S, 146.7253 E, 14 May 2001 ( PS, LS); Billabong Ck at Wanganella , − 35.2124 S, 144.3150 E, 2 April 2001 ( PS, LS); Way Way Ck , − 30.7680 S, 152.9427 E, 24 May 2016 ( BM); Maguire Ck − 28.8367 S, 153.3364 E Jun 2020 (SO); Maguire Ck − 28.8367 S, 153.3364 E ( BM); Tucki Tucki Ck , − 28.8225 S, 153.3362 S, June 2020 (SO); Pinebrush Ck , − 30.1306 S, 153.1328 E ( BM); Small creek in upper reaches of Middle Harbour , Sydney, type locality for P. atacta adynata Riek 1953 ; Wattamollaa Ck on Clinton Park Rd Kangaroo Valley, − 34.7371 E, 150.5929 S, 27 September 2017 ( PS, JM, JH); Kangaroo R at Hampden Bridge , − 34.7272 S, 150.5218 E, 26 September 2017 ( PS, JM, JH); Stream on Broger Rd Shoalhaven catchment, − 34.7105 S, 150.6827 E, 27 September 2017 ( PS, JM, JH); Stream on Jarretts Rd – Upper Kangaroo Valley Rd , − 34.7036 S, 150.5880 E, 27 September 2017 ( PS, JM, JH); Brogers Ck in Shoalhaven catchment, − 34.7105 S, 150.6827 E, 27 September 2017 ( PS, JM, JH); Orara R at Nana Glen , − 30.1328 S, 153.0077 E, no date, (BK); Brogo R at Brogo , − 36.5402 S, 149.8265 E, 10 March 1999; Williams R at Coreei Bridge Dungog , − 32.3968 S, 151.7631 E, 30 October 2011 ( PS, JM, MC); The Falls at Forest Falls Retreat Johns R , − 31.709 S, 152.6612 E, 31 October 2011 ( MC, JM, PS); The Cascades at Forest Falls Retreat Johns R , − 31.70 S, 152.655 E, 31 October 2011 ( MC, JM, PS); Lake Yarrunga at Bendeela recreation area − 34.7398 S, 150.4705 E, 27 September 2017 ( PS, JM, JH) .

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

Queensland: Terrors Ck, Dayboro, type locality for P. australiensis arrostra Riek 1953 ; Upper Nerang R, southern Queensland, type locality for P. atacta Riek 1953 ; Kilcoy Ck, upper Brisbane R, − 26.94 S, 152.568 E, no date (BC); Boar Pocket Ck , Tinaroo , − 17.1708 S, 145.6447 E, 20 October 2017 ( BM, BKr) .

Diagnosis: P. arrostra differs from all other species by the following combination of characters: rostrum variable, long, extending beyond antennular peduncle or extending beyond both the antennular peduncle and scaphocerite, or short not extending beyond the peduncle or intermediate extending beyond peduncle but not the scaphocerite; dorsal edge slightly concave or straight, dorsally armed with 22–34 teeth, 2–3 postorbital spines, ventrally with 3–11 large serrations over a length of 0.40–2.20mm; distal half of ventral edge straight or curved; left mandible with 2–5 (usually 4–5) teeth separated by a smooth angular notch from a distinct apical tooth; right mandible with 4 teeth in 2 separate incisor processes; scaphognathite of maxilla 2 rounded apically extending to apex 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 2.18–3.45 times longer than endopod, epipodite with long podobranchs extending just to basal third of third segment of endopodite; maxilliped 3 with medial distal margin of apical segment of endopod with 6–8 broad teeth-like spines, outer margin with 2 broad teeth-like 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 to apex of carpus; pereiopod 2 with exopod extending to apex of merus or base of carpus; dactylus of pereiopod 3 with prominent terminal claw and 9–11 strong spines on medial margin, exopod extends to mid merus to base of carpus; 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 70–90 small spines on medial margin, exopod extends to mid merus.

Morphotypes of P. arrostra : P. arrostra specimens with a very short rostrum not extending beyond the second segment of the antennular peduncle and only to mid scaphocerite (Lineage 4C) can be distinguished from all other species of Paratya by this short rostrum, dorsal edge straight and curved down at end, dorsally armed with 16–19 spines, 0–1 postorbital spines, with postorbital separated from other rostral spines, ventrally with 4–5 large serrations over a length of 0.60–1.2 mm, extending from posterior of greatest depth; distal half of ventral edge straight ( Table 3).

P. arrostra with the shorter rostrum which does not extend beyond the scaphocerite (lineage 4B) can be distinguished from all other species of Paratya by the following combination of characters: 3–7 ventral spines on rostrum extend over a length of less than 1.80 mm; rostral length approximately equal to scaphocerite length 0.73–1.24; exopod of pereiopod 1, 2 and 3 extending to mid merus to base of carpus.

P. arrostra specimens with the longer rostrum character that extends beyond the end of the scaphocerite (Lineage 4B, 4E) differs from all other species of Paratya by the following combination of characters: 4–11 ventral spines extending over a length of 0.6–2.2 mm; rostral length 1.14–1.31 times longer than scaphocerite length; carpus of pereiopod 1 short; chelae of pereiopod 1 long and slender ( Table 3).

Carapace length 5.10–7.00 mm.

Rostrum variable length either (i, lineages 4B, 4E) long, extending beyond antennular peduncle and to or beyond the end of the scaophocerite (fig. 12a), dorsally slightly concave, moderately slender; length 5.7–7.0 mm, 1.04–1.08 times length of carapace; dorsally armed with 23–34 teeth, ratio of rostral spines to length 4.6–6.67; 2–3 postorbital eye spines (fig. 12a), ventrally with 4–11 large serrations over a length of 1.10–2.2 mm, extending from posterior of, or from, greatest depth (fig. 12a), distal half of ventral edge straight or curved, ratio of ventral spines to rostral length is 0.11–0.34; rostral length 7.86–8.83 times depth, length 1.14–1.31 times length of scaphocerite or (ii lineage 4B) rostrum short, length 2.50–5.30 mm, rostrum not extending beyond antennular peduncle (fig. 12b); 0.63–0.91 times length of carapace, dorsal edge straight and may be angled downwards (fig. 12b); dorsally armed with 22–29 teeth, ratio of rostral spines to length 4.34–7.60, 2–3 postorbital eye spines (fig. 12b), ventrally with 3–7 large serrations over a length of 0.4–1.8mm all forward of greatest depth (fig. 12b), distal half of ventral edge straight; rostral length/depth 6.33–8.83, length 0.73–1.24 times length of scaphocerite or (iii lineage 4C) rostrum very short 3.10–3.50 mm, not extending beyond the second segment of the antennular peduncle (fig. 12c) and only to half scaphocerite, rostral length 0.49–0.60 times length of carapace, shape broad and pointed, dorsal edge straight and curved down at end; dorsally armed with 16–19 teeth (fig. 12c), ratio of dorsal spines to length is 5.15–5.43 and 3.40–4.00 times more spines than ventral spines; 0–1 postorbital eye spines, when present spine distinctly posterior and separated from other rostral spines (fig. 12c); ventrally with 4–5 large serrations over a length of 0.60–1.20 mm, extending from posterior of greatest depth, ratio of ventral spines to rostral length is 0.18–0.34; distal half of ventral edge straight; rostral length/depth, 5.17– 6.60; length 0.80–0.90 times length of scaphocerite.

Antenna 1 (fig. 12d) peduncle not quite reaching distal tip of scaphocerite, but similar length to scaphocerite itself, 0.42–1.06 times as long as scaphocerite; lateral distal angle of first segment with prominent blunt process at outer distal margin with small acute tooth on outer margin of segment but may be absent in some variations. Stylocerite 1.84–2.48 mm long, length 7.21–9.17 longer than width, 0.39–0.41 times carapace length, reaching beyond distal border of peduncle segment (fig. 12d) almost to end of acute process on distal angle of first segment (fig. 12d).

Antenna 2 (fig. 12e) second segment length 1.25–1.68mm long, 0.23–0.34 times length of scaphocerite, 2.00–3.36 longer than width. Scaphocerite 3.70–5.10 mm long, 0.64–0.94 times carapace length and 2.73–4.00 times as long as wide.

Mouthparts. Left mandible (fig. 12g, h) with 2–5 (usually 4–5) teeth separated by smooth angular notch from a distinct acute apical tooth; spine row immediately below incisor process of 8–10 rugose spines (lifting spines); spine row above molar process of approximately over 20 sparsely setose spines. Right mandible (fig. 12i, j) with 4 teeth in 2 separate incisor processes with first and third teeth largest and second and fourth smaller; spine row immediately below teeth with 8–10 spines each finely setose basally; spine row above molar process. Molar process ridged.

Maxilla 1 as for P. australiensis (fig. 12f).

Maxilla 2 as for P. australiensis (fig. 12k).

Maxilliped 1 as for P. australiensis (fig. 12l).

Maxilliped 2 (fig. 12m) endopod length 0.44–1.11 mm; exopod long and narrow, length 2.07–2.69 mm, exopod 2.18– 3.45 longer than endopod. Epipodite with long podobranch extending to basal third of third segment of endopodite.

Maxilliped 3 (fig. 13a) endopod length 5.72–7.23 mm, 2.20–2.75 times longer than exopod, with 3 distal segments of similar length; basal segment curved, apical segment with large terminal claw, medial distal margin with 6–8 broad teeth-like spines, largest 2 or 3 in basal half, outer margin with 2 long teeth-like spines in apical third. Exopod long and narrow 2.33–3.07 mm, tip over-reaching distal end of basal endopod segment.

Thoracic appendages. Pereiopod 1 (fig. 13b) length 3.51– 5.23 mm, 0.66–0.89 times carapace length. Chelae short and slender (fig. 13b), 1.14–2.08 mm long, propodus 2.50–3.47 times as long as wide, 1.72–3.06 times longer than dactylus, 1.08–1.84 times longer than carpus; palm length 1.13–1.90 times palm width and 0.78–2.09 times dactylus length. Carpus long, 1.95–2.76 times as long as greatest width, broadening distally, distal margin excavate. Merus approximately one-third longer than carpus, parallel-sided. Ischium about one-quarter length of merus. Segment ratios 0.59–0.75: 1.08–1.84: 1.00 (1.01–1.40) mm: 1.14–1.84: 0.40–0.50: 1.65–3.16. Exopod extending to mid-apex of carpus.

Pereiopod 2 (fig. 13c) length 5.49–7.69 mm, 0.99–1.99 times carapace length. Chelae long and slender (fig. 13c) 1.15–1.63 mm long, half to two-thirds length of carpus, 2.87– 4.20 times as long as wide; palm length 1.13–2.08 times longer than wide and 1.05–2.00 longer than dactylus. Propodus length 1.43–1.98 times longer than dactylus. Carpus 6.20–8.81 times as long as greatest width, slightly broader distally, distal margin with small excavation. Merus shorter than carpus, parallel-sided. Ischium about half as long as merus. Segment ratios 0.28–0.43: 0.50–0.62: 1.00 (2.29– 2.72) mm: 0.73–0.88: 0.30–0.46: 1.14–1.22. Exopod extending to apex of merus to base of carpus.

Pereiopod 3 (fig. 13d, e) distinctly longer than pereiopod 2 and more slender 7.27–9.24 mm long, 1.28–1.57 times carapace length. Dactylus with prominent terminal claw and 9–11 strong spines on medial margin (fig. 13e). Propodus length 3.58–4.80 times longer than dactylus, length 11.61– 15.77 times longer than wide with 6–13 spines on inner margin. Merus longer than propodus with 1–5 strong spines (usually 2) on medial margin and 1 near ventral distal margin; ischium approximately one-quarter to one-third length of propodus; segment ratios 0.36–0.51: 1.60–1.88: 1.00 (1.39– 1.75) mm: 1.25–2.05: 0.46–0.86: 1.32–1.70. Exopod extends to mid-merus to base of carpus.

Pereiopod 4 (fig. 14a, b) similar to pereiopod 3, 7.69–9.81 mm long, 1.29–1.67 times carapace length. Dactylus with prominent terminal claw and 8–12 spines on medial margin (fig. 14b). Propodus length 3.05–5.00 times longer than dactylus, length 11.11–13.44 times longer than wide, with 11–16 spines on medial margin; merus with 1–3 strong spine on medial margin and 1 near ventral distal margin. Segment ratios 0.37–0.52: 1.59–1.79: 1.00 (1.49–1.93) mm: 1.83–2.38: 0.50–0.68: 1.35–1.50. Exopod extends to mid merus.

Pereiopod 5 (fig. 14c, d) similar length to pereiopods 3 and 4, 7.85–9.19 mm long, 1.37–1.56 times carapace length. Dactylus with prominent terminal claw and very regular, comb-like row of numerous (70–91) small spines on medial margin (fig. 14d). Propodus length 2.97–3.91 times longer than dactylus, length 11.94–18.62 times as long as wide with 9–13 long medial spines and external margin without spines. Carpus approximately half propodus length without any large spines near distal margin. Merus similar length to propodus, with 1 strong medial spine and 1 distal spine; ischium one-third length of propodus; segment ratios 0.46–0.65: 1.79–1.97: 1.00 (1.52–1.80) mm: 1.54–1.97: 0.47–0.66: 1.29–1.61. Exopod extends to mid to apical third of merus.

Abdomen. Pleopods peduncle of first pleopod short, 0.26–0.37 times length of carapace length, 2.40–3.45 times width, exopod 1.29–1.81 times peduncle length, endopod 0.63–0.69 times peduncle length (fig. 14g); second pleopod peduncle short, 0.31–0.47 times length of carapace, 2.47–3.67 times width, exopod 1.09–1.35 times peduncle length, endopod slightly shorter 0.91–1.27 times peduncle length. Length of first peduncle 1.18–1.28 times length of second peduncle. Peduncle of pleopod 5 0.20–0.28 times length of carapace, 1.68–2.31 times width; exopod length 1.57–1.93 times peduncle length; endopod 1.22–1.57 times peduncle length; exopod length 1.14–1.29 times endopod length.

Telson (fig. 14e, f) length 3.10–4.10 mm, 0.51–0.76 times carapace length, 2.36–3.75 times as long as greatest width, and tapering distally, Dorsal surface with 0–2 pairs of strong submarginal teeth-like spines; posterior margin convex with 1 pair of teeth-like spines outermost, 7–13 (usually 11–12) long, strong setose spines (fig. 14f).

Uropods approximately equal to telson length, exopod 1.05–1.33 times telson length, length 2.84–3.19 times width; endopod 0.98–1.29 times telson length, length 3.28–4.25 times width.

Males smaller than females, carapace length 4.36 mm; endopod of first pleopod strongly excavated apically with 9–10 external spines and 10–14 long setae on inner margin (fig. 14h).

Comments: This is the most variable species of Paratya showing distinct rostral characteristics from rostrum shorter than the peduncle, rostrum longer than peduncle but not extending beyond the scaphocerite and rostrum long extending beyond the scaphocerite. Riek (1953) observed these distinct groups and described them as species or subspecies based on morphological character expression only. Williams and Smith(1979) considered all the taxa described by Riek were synonyms of P. australiensis . With the development of molecular techniques, it is now possible to recognise that these variants are all a single taxon and the taxon P. australiensis arrostra Riek is here raised to species level.Genetically, all Lineage 4 specimens have low intraspecific variation, and although Lineage 4C can be reliably identified morphologically ( Table 3), it is slightly more difficult to reliably define lineages 4A, 4B, 4D and 4E ( Cook et al., 2006) morphologically ( Table 2) on the limited material we have been able to analyse. The presence of different morphotypes in this species is similar to the observations by Choy et al. (2019) in the Australian atyid shrimp Australatya .

P. arrostra is widely distributed through the MurrayDarling Basin, south-eastern coastal streams in Victoria and New South Wales, north-eastern New South Wales coastal streams, and south-eastern and northern Queensland (fig. 32a). Lineage 4A has been recorded from northern coastal streams in Queensland but we do not have any specimens of this lineage. Lineage 4C is restricted to south-eastern Queensland in the catchments of the Maroochy R, Mary R and Brisbane R. We have recorded P. arrostra to occur at sites in South Australia with P. rouxi and P. tasmaniensis ; with P. rouxi , P. whitemae and P. strathbogiensis in Murray–Darling Basin rivers and with P. whitemae in coastal rivers.

Gan et al. (2016) defined the complete mitogenome of a species designated as P. australiensis from the Lodden R at Baringhup, Victoria. The mitochondrial genome is 15,990 base pairs in length (GenBank accession number: KM978917) and has 37 mitochondrial genes (13 protein-coding genes, 2 rRNAs and 22 tRNAs) and a non-coding region of 1006 base pairs ( Gan et al. (2016). This genome (strain APR12) was analysed with the total GENBANK Paratya data (Supplementary Table 1) and the species used by Gan et al. (2016) was embedded with P. arrostra .

Figures

Figure 12. Paratya arrostra Riek: a, head region and rostrum of lineage 4 long; b, head region and rostrum of lineage 4 short; c, head region and rostrum of lineage 4c; d, antenna 1 peduncle and stylocerite; e, scaphocerite; f, maxilla 1; g, left mandible; h, enlarged incisors; i, right mandible; j, enlarged incisors; k, maxilla 2; l, maxilliped 1; m, maxilliped 2. Scale lines 0.2 mm.

Figure 13. Paratya arrostra Riek: a, maxilliped 3; b, pereiopod 1; c, pereiopod 2; d, pereiopod 3; e, dactylus 3. Scale lines 0.2 mm.

Figure 14. Paratya arrostra 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, endopod 1 of male. Scale lines 0.2 mm.