Lowryorchestia riparicola, Myers & Park & J.-P, 2025

Myers, Alan A., Park, Eunji & J. - P, Olivier, 2025, A revision of the family Protorchestiidae (Amphipoda: Talitroidea) with the description of two new subfamilies, three new genera and one new species, Zootaxa 5725 (3), pp. 371-390 : 379-382

publication ID	https://doi.org/10.11646/zootaxa.5725.3.3
publication LSID	lsid:zoobank.org:pub:BE16AC59-5F99-4D28-AC42-90002BA7B9B7
persistent identifier	https://treatment.plazi.org/id/8B5D87DC-927D-FF99-FF59-FB1D9C6AFBA1
treatment provided by	Plazi
scientific name	Lowryorchestia riparicola
status	sp. nov.

Treatment

Lowryorchestia riparicola sp. nov.

( Figs 4–9 View FIGURE 4 View FIGURE 5 View FIGURE 6 View FIGURE 7 View FIGURE 8 View FIGURE 9 )

Parorchestia tenuis Park, 2024: 68 View in CoL , fig. 2.

not Parorchestia tenuis (Dana), 1852: 202 View in CoL .

Type material. Holotype male, 10.0 mm. Foxton River Loop Reserve , Foxton, Horowhenua, New Zealand, coll. E. Park. September 5, 2018. (MNZ CR. 027930) . Allotype 1 female, 7.5 mm, same data as holotype. (MNZ CR. 027931) . Paratypes. 4 unsexed. same data as holotype. (MNZ CR. 027932).

Other material. 4 juveniles, Webber Road, Whangaroa, Northland, New Zealand, coll. E. Park, 8, September, 2018 (MNZ CR. 027933) .

Type locality. Manawatu River in Foxton , North Island, New Zealand .

Etymology. Latin: riparius = river bank, together with icola = dwelling

Description. Male 6.0– 10 mm

Head. Eye large, one third length of head. Antenna 1 long, reaching to end of peduncle of antenna 2; flagellum a little shorter than peduncle with 7 articles. Antenna 2 peduncular article 5 longer than article 4, flagellum subequal in length with peduncle with 11 articles, the terminal article rudimentary. Mandible, left lacinia mobilis 4-dentate. Maxilla 1 endopodite slender, bearing 2 terminal plumose setae; exopodite bearing 7 strong toothed robust setae; palp small, 2-articulate. Maxilla 2 endopodite slightly shorter than expodite, weakly truncate distally, lateral margin weakly setose. Maxilliped exopodite relatively narrow, not arcuate, palp broad, article 3 distally broad, article 4 a little longer than broad.

Pereon. Gnathopod 1 coxa deeper than wide, ventral margin with fine setae; basis slender, proximally narrow; merus with palmate lobe on posterior margin; carpus elongate, slender with posterodistal palmate lobe; propodus shorter than carpus, with posterodistal margin expanded into palmate lobe continuous with palm; dactylus shorter than palm. Gnathopod 2 coxa as wide as deep, distal margin convex with small setae, posterior margin with acute process; basis stout, parallel-sided; merus subequal in length with ischium; carpus very short, cup-shaped; propodus large, subovoid, palm smoothly convex, delimited from posterior margin by well-developed shelf bearing a single stout robust seta, palm with continuous array of strong robust setae; dactylus stout, overlapping shelf on posterodistal margin. Pereopods 3–7 simplidactylate. Pereopods 3 and 4 subsimilar, basidactylate, pereopod 4 slightly the longer. Pereopod 5 basis subovate; propodus approximately 1.25 x longer than carpus; dactylus stout. Pereopod 6 basis subovate, posterior margin weakly crenulate; propodus slender approximately 1.25 x length of carpus; dactylus stout. Pereopod 7 only a little longer than pereopod 6; basis with well-developed posterodistal rounded lobe, posterior margin crenulate; propodus slender, 1.5 times longer than carpus; dactylus slender. Gills on coxae 2–6 broad, plate-like unlobed.

Pleon. Pleopods all well developed, pleopod 3 a little shorter that pleopods 1 and 2; peduncles naked; rami long, setose. Epimera 1–3, posteroventral corner with small spine with small seta inserted above it. Epimeron 3 with weak notch above spine. Uropod 1 peduncle outer margin with 4 long robust setae, inner margin with 2 robust setae, small distolateral robust seta 0.25 x length of outer ramus; rami shorter than peduncle; endopodite subequal in length with exopodite with two marginal robust setae, exopodite without dorsal robust setae. Uropod 2 peduncle outer margin with 2 large dorsal robust setae; rami subequal in length with peduncle; subequal in length with each other; endopodite with 3 marginal robust setae. Uropod 3 peduncle with three strong distal robust setae; ramus slender, about half length of peduncle, with 3 subequal apical robust setae. Telson slightly longer than wide, apically weakly incised, without marginal setae, with 1 apical robust seta on each side.

Female. (Sexually dimorphic characters only), 7.0 mm. Gnathopod 1 similar to that of male but palmate lobes less well-developed. Gnathopod 2 mitten-shaped, merus, carpus and propodus with palmate lobes, carpus and propodus subequal in length. Oostegites broad with more than 30 setae with coil tips.

Remarks. L. riparicola sp. nov. differs from all other species of Lowryorchestia by the elongate pereopod 7 ( Fig. 8 View FIGURE 8 ). It shares with the other New Zealand species L. campbelliana , the broadly rounded telson (terminally narrow in all other species. Bousfield (1964) illustrates the strongly coiled tips of the oostegites which appear to be exactly the same as those of L. riparicola sp. nov. A significant male bias is evident in the collected specimens of this species. Samples were collected with fine-mesh (< 0.2 mm) hand nets. The observed bias may reflect sex-based behavioural or habitat differences, but quantitative research is needed to test this hypothesis.

Habitat. On river banks.

Distribution. New Zealand: North Island: Foxton (Horowhenua), Mokoia ( Taranaki), South Featherston ( Wellington), Kaeo ( Northland). South Island: Cedarwood Reserve, Christchurch ( Canterbury), Rangihaeata ( Tasman).