Paratya spinosa, 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 : 72-76

Paratya spinosa n. sp.

Figures 9–11

http://zoobank.org/urn:lsid:zoobank.org:act:2EBBA831-3594-

4725-A47F-530AA42CC609

Lineage 3 ( Cook et al., 2006)

Type Material: Holotype New South Wales. Korrumbyn Ck, Tributary of Tweed R, Mt Warning , − 28.4 S, 153.3 E, no date (BC). Body in ethanol and antennae, mouthparts, pereiopods and abdominal structures dissected, mounted on 2 slides. Accession Ref. MC11 . AM Ref No. P. 105602.001.

Paratypes: New South Wales. Details as for holotype, Accession Ref. MC17 Genbank Registration OL 420818, MC13 bodies in ethanol and other structures dissected, mounted on 2 slides each and 2 whole specimens .

Material Examined: New South Wales: Korrumbyn Ck, Tributary of Tweed R, Mt Warning , − 28.4 S, 153.3 E, no date (BC) .

Diagnosis: P. spinosa differs from all other species by the following combination of characters: rostrum long, extending beyond both antennular peduncle and scaphocerite, dorsal edge straight, dorsally armed with 28–30 teeth, 3 postorbital spines, ventrally with 9–10 large serrations over a length of 1.65–3.00 mm, all forward of greatest depth; distal half of ventral edge straight; left mandible with 4 teeth separated by finely ridged notch from a less distinct apical tooth; right mandible with 4–5 teeth in a single incisor process with all teeth large; 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, approximately half length of caridean lobe; exopod of maxilliped 2 1.06–1.20 times longer than endopod; maxilliped 3 with medial distal margin of apical segment of endopod with 8–13 broad teeth-like spines, outer margin with 1–2 broad teeth-like spines, exopod long and narrow, tip over-reaching distal end of basal endopod segment; pereiopod 1 with long carpus and short and broad chelae; pereiopod 2 with exopod extending to apex of merus; dactylus of pereiopod 3 with prominent terminal claw and 7–9 strong spines on medial margin, exopod extends to apex of merus; dactylus of pereiopod with a prominent terminal claw and 6–12 spines on medial margin, exopod extends to mid merus; dactylus of pereiopod 5 with prominent terminal claw and very regular comb–like row of 44–60 small spines on medial margin, exopod extends to basal third of merus.

Carapace length 6.20 (5.70–6.20) mm.

Rostrum (fig. 9a) long 6.20 (5.70–6.05) mm, extending beyond both antennular peduncle and scaphocerite, rostral length 0.81 (0.81–1.16) times longer than carapace, dorsal edge straight, moderately slender and pointed; rostral length, 6.25 (6.25–8.25) greater than width; dorsally armed with 28 (28– 30) teeth, ratio of rostral spines and rostral length is 5.60 (4.24–5.60), with 1-3 postorbital spines (fig. 9a); ventrally with 9 (8–10) large serrations over a length of 1.65 (1.65–3.0) mm, 1 or 2 spines posterior of greatest depth, distal half of ventral edge straight, ratio of ventral spine length and rostral length is 0.33 (0.33–0.45) with 3.11 (3.00–3.11) times more dorsal spines than ventral spines; rostral length 1.11 (1.11–1.83) times length of scaphocerite.

Antenna 1 (fig. 9b) peduncle 4.45 (3.78–4.56) mm long, not quite reaching distal tip of scaphocerite, length 0.99 (0.89–1.27) times length of scaphocerite. Stylocerite 2.53 (2.2–2.53) mm long, length 7.21 (7.21–9.17) times longer than width, 0.41 (0.39–0.41) times carapace length, reaching beyond distal border of peduncle segment almost to end of broad acute process on distal angle of first segment.

Antenna 2 (fig. 9c) second segment of peduncle 1.50 (1.25–1.68) mm long, 0.33 (0.29–0.47) times length of scaphocerite, 2.50 (2.38–3.23) times longer than wide scaphocerite 4.50 (3.60–4.50) mm long, 0.73 (0.63–0.73) times carapace length, 2.90 (2.57–2.93) times as long as wide.

Mouthparts. Left mandible (fig. 9d, e) with 4 teeth separated by finely ridged notch from a less distinct apical tooth; spine row immediately below incisor process of 10 rugose spines (lifting spines); spine row above molar process of approximately over 20 sparsely setose spines. Right mandible (fig. 9f, g) with 4–5 teeth in a single incisor process, all teeth large and of equal length; spine row immediately below teeth with 9 spines each finely setose basally; spine row above molar process. Molar process ridged.

Maxilla 1 (fig. 9h) palps short, truncate, with 1 long, setose terminal spine and 1 small, simple subterminal one, inner distal angle rounded.

Maxilla 2 palps small, but longer than P. australiensis , terminal parts narrow and with 1 sub-apical setose spine. Scaphognathite rounded apically, extending to apex of upper endite (fig. 9i).

Maxilliped 1 (fig. 9j) palp with broad base, short narrow distal lobe, and several long setose spines on distal margins. Exopod flagellum distinct, well developed and with numerous long setose spines on all margins, approximately half length of caridean lobe.

Maxilliped 2 (fig. 9k) endopod 1.19 (1.19–1.26) mm long; exopod long and narrow, length 1.43 (1.33–1.43) mm, exopod 1.06–1.20 times longer than endopod. Epipodite with podobranch.

Maxilliped 3 (fig. 10a) endopod length 4.03 (3.62–6.33) mm, 2.41 (2.41–2.54) 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 (8–13) broad teeth-like spines, largest in basal third, outer margin with 1 apical broad tooth–like spines. Exopod long and narrow 1.67 (1.43–2.64) mm long, tip extends beyond distal end of basal endopod segment.

Thoracic appendages. Pereiopod 1 (fig. 10b) 4.98 (4.68– 4.98) mm long, 0.80 (0.80–0.82) times carapace length. Chelae short and broad (fig. 10b), 1.65 (1.60–1.68) mm long, propodus 2.87 (2.68–2.87) times as long as wide, 1.83 (1.83– 1.97) times longer than dactylus 1.29 (1.29–1.43) times longer than carpus; palm length 1.47 (1.44–1.79) palm width and 0.94 (0.93–1.06) times dactylus length. Carpus long 2.32 (2.27–2.50) times longer than greatest width, broadening distally, distal margin excavate. Segment ratios 0.71 (0.68– 0.74): 1.29 (1.29–1.43): 1.00 (1.30 [1.12–1.28] mm): 1.20 (1.18–1.30): 0.41 (0.41–0.45): 2.55 (–). Exopod extending to mid carpus.

Pereiopod 2 (fig. 10c) 7.05 (6.71–7.05) mm long, 1.14 (1.11–1.18) times carapace length. Chelae long and slender 1.55 (1.50–1.55) mm long (fig. 10c), 3.10 (3.00–3.19) times longer than wide, 0.65 (0.65–0.69) times carpus length; palm length 1.80 (1.45–1.82) times longer than palm width, 0.77 (0.53–0.77) times length of dactylus. Propodus length 1.77 (1.53–1.77) times longer than dactylus. Carpus 7.38 (5.60– 7.38) times longer than greatest width, slightly broader distally with small excavation. Segment ratios 0.36 (0.36– 0.45): 0.65 (0.65–0.69): 1.00 (2.40 [2.18–2.40] mm): 0.80 (0.80): 0.49 (0.49–0.59): 1.41 (1.41–1.43). Exopod extending to apex of merus.

Pereiopod 3 (fig. 10d, e) distinctly longer than pereiopod 2 and more slender 9.08 (7.48–9.08) mm long, 1.46 (1.31–1.46) times carapace length, dactylus with prominent terminal claw and 9 (7–9) strong spines on medial margin (fig. 10e). Propodus length 4.56 (4.56–4.80) times longer than dactylus, length 12.30 (10.67–12.30) times longer than wide with 8 (6–8) spines on inner margin, outer margin lacks spines. Carpus with 1 large subapical spine. Merus with 1 strong spine on medial margin and 1 near ventral distal margin; segment ratios 0.44 (0.34–0.44): 1.98 (1.64–1.98): 1.00 (1.55 [1.55–1.56] mm): 2.35 (1.58–2.35): 0.52 (0.52–0.57): 1.65 (–). Exopod extends to mid merus.

Pereiopod 4 (fig. 11a, b) similar length to pereiopod 3, 9.08 (7.68–9.20) mm long, 1.46 (1.35–1.52) times carapace length. Dactylus with prominent terminal claw and 7 (7–8) spines on medial margin (fig. 11b). Propodus length 4.96 (4.11–4.96) times longer than dactylus, 12.90 (9.74–13.33) longer than wide, with 10 (6–12) spines on medial margin, outer margin without spines; carpus with large subapical spine; merus with 1 strong spine on medial margin and 1 near ventral distal margin. Segment ratios 0.40 (0.37–0.40): 1.98 (1.50–1.98): 1.00 (1.63 [1.63–1.65] mm): 2.09 (1.69–2.20): 0.51 (0.49– 0.56): 1.71 (1.71–1.82). Exopod extends to mid merus.

Pereiopod 5 (fig. 11c, d). Slightly longer than pereiopods 3 and 4, 9.65 (8.45–9.65) mm long, 1.56 (1.48–1.56) times carapace length. Dactylus with prominent terminal claw and very regular, comb–like row of numerous (44–55) small spines on medial margin (fig. 11d). Propodus length 3.92 (–) times longer than dactylus, length 14.50 (12.6–14.50) times longer than wide with 7 (5–11) long medial teeth, external margin lacking spines. Carpus without large spines near distal margin. Merus with 1 strong medial spine and lacking a distal spine; segment ratios 0.55 (–): 2.16 (1.56–2.16): 1.00 (1.68 [1.50–1.81] mm): 1.85 (1.57–2.23): 0.75 (0.54–0.75): 1.67 (1.21–1.92). Exopod extends to mid merus.

Abdomen. Pleopods peduncle of first pleopod short, 0.40 (0.33–0.40) times length of carapace, 4.17 (3.08–4.17) times longer than wide, exopod 1.14 (1.14–1.43) times peduncle length, endopod (fig. 11g), (0.53–0.58) times peduncle length; second pleopod peduncle short, 0.43 (0.37–0.43) times length of carapace, 2.94 (2.81–3.00) times longer than wide, exopod 1.13 (1.13–1.29) times peduncle length, endopod slightly shorter 1.06 (1.06–1.22) times peduncle length. Length of first peduncle 1.06 (1.06–1.13) times length of second peduncle.

Telson (fig. 11e, f) length 4.41 (3.7–4.41) mm, 0.71 (0.63– 0.71) times carapace length, 3.14 (2.98–3.14) times longer than greatest width and tapering distally. Dorsal surface with 1–2 pairs of strong submarginal teeth-like spines. Posterior margin convex with 1 pair of teeth-like spines outermost, 7 (6–10) long, strong setose spines (fig. 11f).

Uropods approximately equal to telson length.

Males smaller than females, carapace length 4.5 mm; with endopod of pleopod 1 strongly excavate apically with 12 external spines on medial margin and 15 long setae on inner margin (fig. 11i).

Etymology: Spinosa after the very spiny rostrum with 28–30 dorsal spines and 9–10 ventral spines.

Comments: P. spinosa is most similar to P. tasmaniensis but may co-occur with P. walkeri . P. spinosa can be distinguished from all other long rostrum species by the combination of characters listed in Table 2 including the number of dorsal rostral spines (28–30); number of ventral rostral spines (9–10); right mandible incisors with 4–5 teeth; shape of scaphognathite of maxilla 2.

P. spinosa has a restricted distribution in streams of the northern coastal streams in New South Wales (Tweed R catchment) while P. tasmaniensis is widespread in Tasmania, coastal Victoria, New South Wales and Queensland and in the Murray-Darling catchment in New South Wales and South Australia. Cook et al. (2006) recorded lineage 3 in the Clarence R system but we recorded P. spinosa only in the Tweed R system. It is possible that both P. spinosa and P. walkeri may coexist in the Tweed R.

Figures

Figure 9. Paratya spinosa 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 10. Paratya spinosa sp. nov.: a, maxilliped 3; b, pereiopod 1; c, pereiopod 2; d, pereiopod 3; e, dactylus 3. Scale lines 0.2 mm.

Figure 11. Paratya spinosa 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; h, pleopod 1 of male; i, endopod 1 of male. Scale lines 0.2 mm.