Aotearorchestia telluris ( Spence Bate, 1862 ) Hughes & Lowry, 2023

Hughes, Lauren E. & Lowry, James K., 2023, Review of New Zealand Coastal Talitroids with description of three new genera (Crustacea, Amphipoda, Senticaudata), Zootaxa 5268 (1), pp. 1-81 : 18-24

Aotearorchestia telluris ( Spence Bate, 1862) comb. nov.

( Figs. 11–19 , 66–67 )

Orchestia telluris Spence Bate, 1862: 20 , pl. 3, fig. 6; pl. 4, fig. 4.— Miers, 1876: 122.—G.M. Thomson, 1881: 209.— Thomson & Chilton, 1886: 145.—G.M. Thomson, 1913: 244.

Orchestia gammarellus .— Della Valle, 1893: 500 (in part).

Talorchestia telluris .— Stebbing, 1906: 551.— Chilton 1927: 175.— Stephensen, 1935: 12.— Stephensen, 1948: 13.— Hurley, 1956: 373, figs. 81–107.

Not Talorchestia telluris .— Chilton, 1917: 299–302 (in part), figs. 17, 18 (= H. chathamensis ( Hurley, 1956)) .

Type material examined. Syntypes: male, 12.7 mm [10/20 th of an inch]; female, 8.9 mm [7/20 th of an inch], dry pinned, BMNH 1844.3 (39), under dead leaf, coll. Mr Hook, HMS Erebus and Terror Expedition .

Material examined. 4 specimens (1 female 11 mm, 3 males 11 mm, 11 mm, 13 mm), BMNH 1928.12.1.2454– 2456, New Zealand, no other location details, Stebbing Collection ; 11 specimens (including a male, 12 mm, SEM whole animal pin mount, parts on stubs; b male, 11 mm, dissected (parts in microvial); c male*, 12 mm, dissected (parts in microvial), NIWA 104075 , stream side of dunes, Kaikorai Stream mouth, Dunedin (45 55′54″S 170 23′23″E), collected on the freshwater side of the dunes, fringing the entrance of a stream into the sea, September 1953 (station Z1603) ; 4 specimens NIWA 104076 , Oruaiti Beach , East Cape (37°36′56″S 177° 56′33″E), collected from fine yellow sand next to stagnant pool of water well above high-tide mark, specimens active and jumped into the pool when disturbed and swam vigorously, 1 November 1951 (station Z16054) .

Type locality. New Zealand .

Diagnosis. Gnathopod 2 without proximal spine defining palm, palm with large projections near dactylar hinge. Pereopod 7 carpus greatly enlarged, ovate.

Description (based on a male, 12 mm, b male, 11 mm, c male, 12 mm, NIWA 104075, ‘x’ female, 7.5 mm, NIWA 8387). Head. Eye medium size (greater than 1/5 to 1/3 head length). Antenna 1 long, reaching midpoint of peduncular article 5 of antenna 2. Antenna 2 less than half body length (0.28 × length); peduncular articles slender, with many large robust setae; article 5 longer than article 4; flagellar articles final article large, cone-shaped forming a virgula divina. Upper lip without apical setal patch; epistome with many robust setae. Lower lip distolateral setal tuft present, distomedial setal tuft present; without inner plates. Mandible left lacinia mobilis 4-cuspidate. Maxilla 1 with 1-articulate small palp. Maxilliped palp article 2 distomedial lobe well-developed; article 4 fused with article 3.

Pereon. Gnathopod 1 sexually dimorphic; subchelate; coxa smaller than coxa 2; carpus longer than propodus, 1.5 × as long as propodus, posterior margin with palmate lobe; propodus distally broad, twice as long as broad, anterior margin with 5 groups of robust setae, posterior margin with palmate lobe, palm transverse; dactylus simplidactylate, over-reaching palm length, without anterodistal denticular patch. Gnathopod 2 sexually dimorphic; subchelate; basis slender; ischium anterior margin with lateral and medial rounded lobe, lobes similar in size; carpus triangular, reduced, enclosed by merus and propodus; propodus 1.5–1.6 × as long as wide, palm subacute, 60% along posterior margin, evenly rounded, with subacute distomedial tooth, lined with robust setae, posteroproximal corner with groove, without cuticular patch at corner of palm; dactylus curved, subequal in length to palm, without anteroproximal bump, apically acute. Pereopods 3–4 coxae deeper than wide. Pereopods 3–7 asymmetrically tricuspidactylate laterally, dactylus without anterodistal denticular patch. Pereopod 3 carpus length twice width. Pereopod 4 significantly shorter than pereopod 3; carpus significantly shorter than carpus of pereopod 3, length 1.5 × width; dactylus without anterodistal denticular patch, posterior margin thickened proximally with 1 proximal and 1 distal projections. Pereopod 5 merus length 1.5 × width; carpus length twice width; propodus distinctly longer than carpus, length 4 × width; dactylus long, slender, length 5 × width. Pereopod 6 subequal in length to pereopod 7; coxa posterior lobe posteroventral corner rounded, crenulate, posterior margin perpendicular to ventral margin; merus broad, length twice width; carpus length 4 × width; propodus longer than carpus, length 6 × width. Pereopod 7 basis expanded, produced posteriorly, posterior margin convex, serrate, lined with small robust setae, lateral sulcus strongly pronounced; merus developed as a 3-dimensional complex article (see SEM image, Fig. 18 ), length 1.1 × width; carpus subovate, length 1.5 × width; propodus subequal to carpus, length 6.1 × width.

Pleon. Pleonites 1–2 without dorsal spines. Pleonite 3 without pair of well-developed carina. Pleopods 1–3 reduced, rami unsegmented. Epimera 1–2 posterior margin straight, smooth to weakly serrate. Epimeron 3 posteroventral corner produced, ventral margin without robust setae, posterior margin straight, smooth to weakly serrate, lined with robust setae. Uropod 1 not sexually dimorphic; peduncle with 13 robust setae, with apical spearshaped setae; rami positioned directly on top of each other; endopod subequal in length to exopod, with 7 marginal robust setae in 2 rows; exopod with 4 marginal robust setae. Uropod 2 peduncle with 11 robust setae; endopod subequal in length to exopod, with 6 marginal robust setae in 2 rows; exopod with 3 marginal robust setae in 1 row. Urosomite 3 subrectangular, not engulfing telson, broader than deep, 1.5 × as broad as deep. Uropod 3 margin not accommodating telson, length twice depth, with 6 robust setae; ramus linear, not fused to peduncle, longer than peduncle, 4 × as long as broad, with row of 12 marginal setae. Telson subovate, margins convex, weakly incised apically, dorsal midline entire, with 12–13 dorsal, marginal and apical robust setae per lobe; length not extending beyond uropod 3 peduncle.

Variation. The male gnathopod 2 propodus shows relatively little variation, with the proximal palmar tooth more produced and apically acute in larger individuals (12+ mm). The expansion of the pereopod 7 carpus develops posteriorly (with the dorsal and ventral margins parallel) and the medial surface becoming more convex in larger growth stages.

Size. Males 13 mm; females 11 mm.

Remarks. See remarks for A. chathamensis .

Habitat. Supralittoral.

Distribution. New Zealand. North Island: Waiwera; Auckland; Orouiti Beach ( Chilton 1917; Hurley 1956). South Island: Kaikoura; St Kilda; Dunedin ( Hurley 1956). Stewart Island ( Thomson 1880, 1913).

Figures

FIGURE 11. Aotearorchestia telluris (Spence Bate, 1862) gen. et comb. nov., Whangarei Heads, Taurikura Bay, image captured 26 April 2006, photographer R.B. Taylor.

FIGURE 12. Aotearorchestia telluris (Spence Bate, 1862) gen. et comb. nov., c male, 12 mm, NIWA 104075, stream side of dunes, Kaikorai Stream mouth, Dunedin, New Zealand.

FIGURE 13. Aotearorchestia telluris (Spence Bate, 1862) gen. et comb. nov., b male, 11 mm, c male, 12 mm, NIWA 104075, stream side of dunes, Kaikorai Stream mouth, Dunedin, New Zealand. Scales, 2 mm.

FIGURE 14. Aotearorchestia telluris (Spence Bate, 1862) gen. et comb. nov., b male, 11 mm, c male*, 12 mm, NIWA 104075, stream side of dunes, Kaikorai Stream mouth, Dunedin, New Zealand. Scales, 2 mm.

FIGURE 15. Aotearorchestia telluris (Spence Bate, 1862) gen. et comb. nov., a male, 12 mm, SEM image, NIWA 104075, stream side of dunes, Kaikorai Stream mouth, Dunedin, New Zealand. Scales, Ep, 1 mm; LL, 300 μm; Md, UL, 200 μm; Mxp, 150 μm; Mx2, 100 μm.

FIGURE 16. Aotearorchestia telluris (Spence Bate, 1862) gen. et comb. nov., a male, 12 mm, SEM image, NIWA 104075, stream side of dunes, Kaikorai Stream mouth, Dunedin, New Zealand. Scales, G1, A2, 500 μm; G2, 1 mm; A1, 250 μm.

FIGURE 17. Aotearorchestia telluris (Spence Bate, 1862) gen. et comb. nov., male, 12 mm, SEM image, NIWA 104075, stream side of dunes, Kaikorai Stream mouth, Dunedin, New Zealand. Scales, 100 μm.

FIGURE 18. Aotearorchestia telluris (Spence Bate, 1862) gen. et comb. nov., male, 12 mm, SEM image, NIWA 104075, stream side of dunes, Kaikorai Stream mouth, Dunedin, New Zealand. Scales, 1 mm, except P7 dactylus, 100 μm.

FIGURE 19. Aotearorchestia telluris (Spence Bate, 1862) gen. et comb. nov., a male, 12 mm, SEM image, NIWA 104075, stream side of dunes, Kaikorai Stream mouth, Dunedin, New Zealand. Scales, Ep, Ur, U1, 500 μm; U2, 250 μm; U3, T, 200 μm.

FIGURE 66. Comparison of male pereopod 7 dimorphism. A. Aoteororchestia chathamensis comb. nov. (Hurley, 1956) B. Aoteororchestia telluris (Spence Bate 1862) comb. nov. C. Hermesorchestia alastairi Hughes & Lowry, 2017 D. Gondwanorchestia scutigerula (Dana, 1852a) E. Africorchestia tricornuta (Shoemaker, 1920).

FIGURE 67. Fieldguide to New Zealand Coastal Talitrids Bellorchestia quoyana (Milne Edwards, 1840), Aotearorchestia chathamensis (Hurley, 1956) gen. et comb. nov., A. telluris (Spence Bate 1862) comb. nov., Transorchestia serrulata (Dana, 1852a), T. miranda (Chilton, 1916) (Part 1 of 3).