Paratya walkeri, Suter & Mynott & Crump, 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 : 65-72

Paratya walkeri n. sp.

Figures 6–8

http://zoobank.org/urn:lsid:zoobank.org:act:E03B305A-0EDD-

4ABD-92E8-566AE860E9E0

Lineage 2 ( Cook et al., 2006)

Type material: Holotype New South Wales. Dingo Ck , − 30.3103 S, 152.9822 E, 24 May 2015 ( BM) PS9 . Body in ethanol and antennae, mouthparts, pereiopods and abdominal structures dissected, mounted on 2 slides. Accession Ref. PS9 . Australian Museum ( AM) Ref No. P. 105600.001.

Character Paratya Paratya Paratya Paratya arrostra Paratya Paratya Paratya Paratya Paratya australiensis walkeri spinosa williamsi whitemae strathbogiensis tasmaniensis gariwerdensis L4B

L1 L2 L3 L5 L6 L7 L8 LD Carapace length (mm) 4.1–8.0 5.75–6.25 5.70–6.20 5.10–7.00 4.85–6.00 4.5–6.6 5.6–6.5 5.40–7.50 3.6–4.1 Rostrum longer than carapace − + −/= +/− +/= = − + − Rostrum extends beyond scaphocerite +/− + + +/− = + + + − Number of dorsal rostral spines 16–17 or 16–28 24–30 28–30 22–34 21–27 20–34 21–24 22–29 26–28 Number of post-orbital spines 0 or 1–3 2–4 1–3 2–3 2–3 1–4 1–2 2–4 2 Number of ventral rostral spines 2–5 or 4–7 14–16 8–10 4–11 1–5 4–14 4–6 4–13 7–10 Number of ventral spines posterior to 0 1–2 0–1 0–1 0–1 1–2 0 0 2–3 greatest depth of rostrum

Length of ventral rostral spine row 0.6–1.5 2.75–4.00 1.65–3.00 1.10–2.20 0.10–2.00 1.30–2.80 1.30–1.80 2.10–3.40 1.30–1.50 (mm)

First pereiopod carpus length Long, Short, Short, Short, Short. Short, Short, Short to long, Very short, 1.73–2.84 mm 1.25–1.35 mm 1.12–1.28 mm 1.01–1.40 mm 1.05–1.10 mm 0.87–1.40 mm 1.13–1.47 mm 1.00– 2.67 mm 0.88–0.90 mm First pereiopod chelae shape Short to long Long and Short and Short and slender Short and Short and Short and broad to Short and broad to Short and and slender broad broad broad broad long and slender long and slender broad First pereiopod Propodus length/ 1.04–1.71 1.30–1.44 1.29–1.43 1.08–1.84 1.27–1.44 1.14–1.49 1.19–1.31 1.25–1.41 1.26–1.33 carpus length

First pereiopod propodus length/width 2.55–3.46 2.64–3.04 2.68–2.87 2.50–3.47 2.28–3.02 2.48–3.84 2.86–3.26 2.95–3.43 2.44–3.07 First pereiopod palm length/palm 1.58–1.91 1.48–1.65 1.44–1.79 1.13–1.90 1.36–1.70 1.56–2.25 1.42–2.14 1.60–1.83 1.39–1.67 width

Second pereiopod palm length/palm 1.71–1.98 1.50–1.61 1.45–1.82 1.13–2.08 1.50–1.56 1.50–2.50 2.00–2.22 1.80–3.35 1.22–1.53 width

Second pereiopod propodus length/ 1.61–2.07 1.56–2.06 1.53–1.77 1.43–1.98 1.76–1.80 1.39–1.91 1.67–1.81 1.57–2.06 1.77–2.04 dactylus length

Dactylus 3 teeth 7–11 7–10 7–9 9–11 5–7 7–11 8–13 9–11 6–7 Dactylus 4 teeth 6–11 7–8 7–9 8–12 5–6 8–11 9–12 8–12 7–8 Dactylus 5 comb 55–80 53–62 44–60 70–91 49–66 81–94 64–80 70–85 70–80 Telson length/carapace length 0.55–0.73 0.64–0.74 0.63–0.71 0.51–0.76 0.67–0.72 0.58–0.83 0.57–0.66 0.59–0.70 0.67–0.70 Number of long terminal spines of 6 9–10 6–10 7–13, (usually 8 8–10 8–12 8–12 6–7 telson 11–12)

Right mandible incisors Incisors paired Incisors single Incisors single Incisors single 1 Incisors single Incisors single Incisors paired Incisors single Incisors single each with 2 with 4 teeth, with 4–5 and 3 large, 2 and with 4 teeth, 3 with 3–4 outer with 2 teeth with 4–5 teeth, with 4 teeth, teeth, 1 and 3 tooth 2 teeth, all large 4 slightly shorter and 4 teeth teeth, 2 central 1 and 3 large with tooth 3 largest, 1, 1, 2 and 4 large, 2 and 4 largest, 1, 3, 4 and of equal largest 1 and 2 teeth largest, 1 2 very short, 4 2 and 3 smaller smaller than 3 shorter shorter size shorter and 4 shorter large, 3 and separated

Maxilla 2 scaphognathite Rounded Truncated Rounded Rounded apically, Truncated Rounded Truncated Truncated Truncated apically, not apically, not not truncated apically, not truncated truncated truncated

Distribution NSW Sydney NSW NSW northern Widespread, NSW, Coastal Vic, streams in the Tasmanian, SA, South-west streams northern coastal rivers Murray–Darling Kangaroo streams of Strathbogie Vic and NSW Vic in streams (Parramatta coastal rivers (Tweed River) Basin SA, Coastal Valley, NSW and Vic, Ranges coastal, inland draining the and (Tweed and streams Vic, Shoalhaven south-east Qld streams of the Grampian Shoalhaven Clarence north-east NSW, catchment Murray–Darling Mountains rivers) rivers) south-east Qld. Basin

Note: L1, L2, L3 etc. refer to the lineage of previous publications mentioned in the text.

Paratypes: New South Wales. 5 specimens in ethanol same data as holotype; Accession Ref. PS23 , PS8 Genbank Registration OL 420929; body in ethanol and other structures dissected, mounted on 2 slides each; AM Ref No. P. 105601 ; 3 specimens in alcohol.

Material Examined: New South Wales: Dingo Ck , − 30.3103 S, 152.9822 E, 24 May 2015 ( BM) .

Diagnosis: P. walkeri differs from all other species by the following combination of characters: rostrum long, extending beyond both antennular peduncle and scaphocerite, dorsal edge very slightly concave, dorsally armed with 24–30 teeth, 2–4 postorbital spines, ventrally with 14–16 large serrations over a length of 2.75–4.00 mm, extending from just posterior of greatest depth; distal half of ventral edge straight; left mandible with 3 teeth separated by a notch from 2 less distinct apical teeth; right mandible with 4 teeth in a single incisor process; scaphognathite of maxilla 2 truncated distally not extending to apex of upper endite; maxilliped 1 with exopod flagellum distinct, well developed and with numerous long setose spines on all margins, approximately two-thirds length of caridean lobe; exopod of maxilliped 2 1.09–2.13 times longer than endopod, maxilliped 3 with medial distal margin of apical segment of endopod with 6–12 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, robust chelae, exopod extending to mid to apex of carpus; pereiopod 2 with exopod extending to mid-apex of merus; dactylus of pereiopod 3 with prominent terminal claw and 7–10 strong spines on medial margin, exopod extends to mid merus; dactylus of pereiopod 4 prominent terminal claw and 7–8 spines on medial margin, exopod extends to apical third of merus; dactylus of pereiopod 5 with prominent terminal claw and very regular comb-like row of 53–60 small spines on medial margin, propodus with 8–11 medial spines; exopod extends to basal third to mid third of merus. Telson with 9–10 long terminal spines.

Carapace length 6.25 mm (5.75–6.25).

Rostrum long, 6.3 mm (5.75–6.60), extending beyond both antennular peduncle and scaphocerite (fig. 6a), rostral length 1.08 (0.95–1.15) times longer than carapace, dorsal edge curved upwards to tip, broad and pointed, rostral length 9.00 (6.76–9.00) times greater than width; dorsally armed with 29 (24–30) teeth, ratio of rostral spines to rostral length is 4.60 (4.17–4.60); 4 (2–4) postorbital spines; ventrally with 16 (14– 16) large serrations (fig. 6a) over a length of 4.00 mm (2.75– 4.00), 2 (1–2) spines posterior to widest point; ratio of ventral spine length to rostral length is 0.63 (0.42–0.63) and 1.81 (1.60–2.14), more dorsal spines than ventral spines; rostral length 1.42 (1.25–1.42) times length of scaphocerite.

Antenna 1 peduncle 3.88 (3.40–4.70) mm long, not reaching distal tip of scaphocerite (fig. 6b), 0.87 (0.81–0.91) times length of scaphocerite. Stylocerite 2.88 (2.18–2.88) mm long, length 11.50 (7.25–11.50) longer than wide, 0.46 (0.36– 0.46) times carapace length, reaching beyond distal border of peduncle segment to mid or apex of broad acute process on distal angle of first segment.

Antenna 2 (fig. 6c) apical segment of peduncle 1.55 (1.55– 1.60) mm long, 0.35 (0.34–0.35) length of scaphocerite, 2.70 (2.56–2.70) longer than wide. Scaphocerite 4.45 (4.45–4.70) mm long, 0.71 (0.71–0.82) times length of carapace, 3.30 (3.24–3.68) longer than wide.

Mouthparts. Left mandible (fig. 6d, e) with 3 teeth separated by a notch from 2 less distinct apical teeth; spine row immediately below incisor process of 6 rugose spines (lifting spines); spine row above molar process of approximately over 20 sparsely setose spines. Right mandible (fig. 6f, g) with 4 teeth in a single incisor process with tooth 2 largest; spine row immediately below teeth with 7 lifting spines; spine row above molar process. Molar process ridged.

Maxilla 1 (fig. 6h) as for P. australiensis .

Maxilla 2 scaphognathite truncated distally (fig. 6i), not extending to apex of upper endite.

Maxilliped 1 (fig. 6j) palp with broad base, short narrow distal lobe, and several long setose spines on distal margins. Exopod flagellum distinct, well developed, longer than P. australiensis with numerous long setose spines on all margins, approximately Two-thirds to equal length of caridean lobe.

Maxilliped 2 (fig. 6k) endopod 1.14 (1.11–1.30) mm long, exopod long and narrow 2.35 (1.43–2.38) mm long, exopod 2.03 (1.09–2.13) times longer than endopod. Epipodite with podobranch.

Maxilliped 3 (fig. 7a) endopod length 7.38 (7.05–7.58) mm, 2.68–2.69 times longer than exopod, with 3 distal segments of similar length; basal segment curved, apical segment with large terminal claw, medial distal margin with 7 (6–12) broad teeth-like spines, largest 1 in basal third, outer margin with 1 apical tooth-like spine and 1 paired sub-apical setae. Epipodite with basal conical projection.

Thoracic appendages. Pereiopod 1 (fig. 7b) 5.20 (5.12– 5.28) mm long, 0.83 (0.83–0.92) times carapace length. Chelae long and broad or short and broad, 1.75 (1.75–1.85) mm long, propodus 3.04 (2.64–3.04) times longer than wide, 2.00 (1.85–2.18) times longer than dactylus, 1.30 (1.30–1.44) times longer than carpus; palm length 1.48 (1.48–1.65) times width and 1.03 (1.03–1.32) dactylus length. Carpus long 2.45 (2.00–2.45) times as long as greatest width, broadening distally, distal margin excavate. Segment ratios 0.65 (0.65– 0.78): 1.30 (1.30–1.44): 1.00 (1.35 [1.25–1.35] mm): 1.15 (1.15–1.24): 0.41 (0.38–0.42): 2.50 (2.50–2.68). Exopod extending to mid to apex of carpus.

Pereiopod 2 (fig. 7c) 7.45 (7.15–7.48) mm long, 1.19 (1.18– 1.30) times carapace length. Chelae long and slender 1.70 (1.58–1.68) mm long, nearly two-thirds length of carpus, 2.96 (2.96–3.53) times longer than wide, palm length 1.61 (1.50– 1.61) times width and 1.12 (0.70–1.12) times dactylus length. Propodus 2.06 (1.56–2.06) times longer than dactylus. Carpus 7.69 (6.79–7.69) times as long as greatest width, slightly broader distally, distal margin with small excavation. Segment ratios 0.33 (0.33–0.43): 0.68 (0.66–0.68): 1.00 (2.50 [2.38– 2.50] mm): 0.80 (0.78–0.82): 0.49 (0.49–0.57): 1.36 (1.30– 1.41). Exopod extending to apex of merus to base of carpus.

Pereiopod 3 (fig. 7d, e) distinctly longer than pereiopod 2 and more slender 8.65 (8.55–9.70) mm long, 1.38 (1.38–1.69) times carapace length. Dactylus with prominent terminal claw and 7 (7–10) strong spines on medial margin (fig. 7e). Propodus length 5.26 (4.28–5.33) times longer than dactylus, length 15.13 (13.78–15.13) times longer than wide with 9 (7–10) spines on inner margin. Merus with 1 strong spines on medial margin and 1 near ventral distal margin; segment ratios 0.33 (0.32–0.40): 0.68 (0.66–0.68): 1.00 (1.65 [1.63– 1.80] mm): 0.80 (0.78–0.82): 0.49 (0.50–0.57: 1.36 (1.30– 1.41). Exopod extends to mid merus.

Pereiopod 4 (fig. 8a, b) similar to pereiopod 3, 9.35 (9.18– 9.35) mm long, 1.50 (1.50–1.60) times carapace length. Dactylus with prominent terminal claw and 7 (7–8) spines on medial margin (fig. 8b). Propodus length 4.44 (3.97–4.44) times longer than dactylus, length 13.33 (11.90–14.40) times longer than wide, with 11 (10–13) spines on medial margin; merus with only 1 strong spine on medial margin and 1 near ventral distal margin. Segment ratios 0.35 (0.39–0.49): 1.83 (1.70–2.00): 1.00 (1.75 [1.63–1.75] mm): 1.85 (1.85–2.15): 0.56 (0.51–0.62): 1.70 (1.67–1.75). Exopod extends to middle third of merus.

Pereiopod 5 (fig. 8c, d) similar length to pereiopods 3 and 4, 9.15 (9.08–9.28) mm long, 1.46 (1.46–1.61) times longer than carapace. Dactylus with prominent terminal claw and very regular, comb–like row of 53 (53–62) small spines on medial margin (fig. 8d). Propodus length 4.25 (3.68–4.25) times longer than dactylus, length 17.00 (15.00–17.00) times longer than wide with 8 (8–11) long medial teeth and setae on external margin. Carpus with 1 large spines near distal margin. Merus with 1 strong medial spine and 1 distal spine; segment ratios 0.47 (0.47–0.60): 2.00 (2.00–2.19): 1.00 (1.70 [1.63–1.70] mm): 1.76 (1.72–1.82): 0.62 (0.61–0.69): 1.61 (1.43–1.61). Exopod extends to mid merus (basal third to mid third of merus).

Abdomen. Pleopod peduncle of first pleopod short, 0.26 (0.26–0.37) times length of carapace length, 2.36 (2.36–4.30) times width, exopod 0.73 (0.73–1.40) times peduncle length, endopod 0.70 times peduncle length (fig. 8g); second pleopod peduncle short, 0.36 (0.29–0.36) times length of carapace, 2.64 (1.67–2.64) times width, exopod 1.29 (1.29–1.54) times peduncle length, endopod slightly shorter 1.13 (1.13–1.46) times peduncle length.

Telson (fig. 8e, f) length 4.00 (4.00–4.25) mm, 0.64 (0.64–0.74) times carapace length, 3.64 (2.86–3.64) times as long as greatest width, tapering distally. Dorsal surface with 2 pairs of strong submarginal teeth-like spines. Posterior margin convex with 1 pair of teeth-like spines outermost, 7 (7–8) long, strong setose spines (fig. 8f).

Uropods approximately equal to telson length.

Males unknown.

Etymology: Named after Dr Terry Walker whose study of Paratya in Tasmania ( Walker, 1973) initiated subsequent taxonomic and morphometric studies ( Smith and Williams, 1980; Williams, 1977; Williams and Smith, 1979) and who has encouraged this morphological study.

Comments: Paratya walkeri may be confused with P. australiensis , P. arrostra and P. whitemae due to the very long rostrum that is slightly concave. P. walkeri can be differentiated from all the long rostrum species by the combination of characters in Table 2, including the number of dorsal rostral spines (24–30), number of post orbital spines (2–4), number of ventral spines (14–16) over a length of 2.75–4.00 mm; dactylus 4 with 7–8 medial spines; 1–2 ventral rostral spines posterior to maximum rostrum width.

Distribution: P. walkeri is restricted to the northern coastal rivers of New South Wales in the Tweed R and Clarence R catchments. Cook et al. (2006) recorded this species only in the Tweed R; we recorded it in the Manning R system but not at the Tweed R site. It is possible that P. walkeri and P. spinosa may coexist.

Figures

Figure 6. Paratya walkeri sp. nov.: 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 7. Paratya walkeri sp. nov.: a, maxilliped 3; b, pereiopod 1; c, pereiopod 2; d, pereiopod 3; e, dactylus. Scale lines 0.2 mm.

Figure 8. Paratya walkeri sp. nov.: a, pereiopod 4; b, dactylus 4; c, pereiopod 5; d, dactylus 5; e, telson; f, telson terminal spines; g, pleopod 1 of female. Scale lines 0.2 mm.