Metaprotella lowryi, Hughes & Takeuchi, 2023

Hughes, Lauren Elizabeth & Takeuchi, Ichiro, 2023, A New Species of Metaprotella (Crustacea: Amphipoda: Caprellidae) from One Tree Island, Southern Great Barrier Reef, Queensland, Australia, Records of the Australian Museum (Rec. Aust. Mus.) 75 (4), pp. 431-436 : 432-435

Metaprotella lowryi sp. nov.

urn:lsid:zoobank.org:act:A302BC56-E2AA-416D-9C77-14F6DD7D1CD3

Figs 1–3

Holotype: Male , 7.08 mm, AM P.100147, outer reef of north of Third Lagoon, One Tree Island, 23°29'05"S 152°04'07"E, 18 m depth, Halimeda sp. , QLD 1983, coll. I. Takeuchi & J. K. Lowry, 27 October 2006 . Paratypes: Male , 8.59 mm, AM P.100148, outer reef north of Third Lagoon, One Tree Island, 23°29'05"S 152°04'07"E, 12 m depth, white hydroids, QLD 1984, coll. I. Takeuchi & J. K. Lowry, 27 October 2006, coll. I. Takeuchi & J. K. Lowry ; 1 mature female, 6.02 mm, AM P.100149, outer reef north of Third Lagoon , One Tree Island, 23°29'05"S 152°04'07"E, 12 m depth, white hydroids, QLD 1984, coll. I. Takeuchi & J. K. Lowry, 27 October 2006 .

Type locality. Outer reef north of Third Lagoon , One Tree Island, southern Great Barrier Reef, Queensland, Australia, 23°29'05"S 152°04'07"E .

Etymology. Named for the late Dr J. K. Lowry in recognition of his contribution to Amphipodology.

Description. Male (based on holotype, 7.08 mm, AM P.100147). Head and pereonites slender.

Head. With paired anteriorly curved dorsal projections and small subocular projection (i.e. projection just below the eye). Eyes large, distinctive. Antenna 1 slender, 0.60 times body length; peduncle article 2 longest; peduncular article 3 0.70 times peduncle article 2 length; flagellum 0.70 times peduncular length, with 16 articles. Antenna 2 slender; 0.5 times antenna 1 length; peduncle not strongly setose.

Upper lip notched, forming rounded quadrilateral projections. Mandible right incisor with 5 teeth; lacinia mobilis with 1 plate and 2 teeth, with 2 bundled setal rows; palp 3-articulate, article 3 setal formula 1-8-3-1; molar well developed, with flake. Mandible left incisor with 5 teeth; lacinia mobilis with 5 teeth, 3 bundled setal rows; palp 3-articulate; article 3 setal formula 1-9-3-1; molar well developed. Lower lip finely setose on inner and outer lobes. Maxilla 1 outer plate with 7 stout apical setal-teeth (palp lacking during dissection). Maxilla 2 inner plate triangular, with 7 setae; outer plate elongate, with approximately 15 apical setae. Maxilliped basal endite (inner plate) subquadrate, with 1 small nodular setae, with 4 setae near distal margin; ischial endite (outer plate) oval, 2.5 times length of inner plate, inner margin blade-like, with many fine setae, with 1 large seta on apical lateral margin, with 2 setae on middle lateral margin; palp article 2 setose on inner margin; palp article 3 expanded, with moderately dense distal setae; palp article 4 (dactylus) weakly falcate.

Pereon. Pereonite 2 with small anterolateral projection, with small midlateral projection, with paired anteriorly curved mid-dorsal projections, with curved dorsodistal projection. Pereonite 3 with anterolateral projection, with paired anteriorly curved mid-dorsal projections, with anteriorly curved dorsodistal projection. Pereonite 4, longest, with anterolateral projection. Pereonite 5, next to pereonite 4 length, with anterolateral projection. Pereonites 6 and 7 not articulated obliquely.

Gnathopod 1 carpus setose; propodus subtriangular, palm inserting at 0.1 along posterior margin, minutely serrate, with 1 robust seta near corner of palm, dactylus slightly curved. Gnathopod 2 inserting at 0.20 along anterior margin of corresponding pereonite; coxa vestigial; basis 0.7 times length of pereonite 2, with acute projection near distal margin; propodus subovate, large, length 2 times width palm margin straight, smooth, with grasping projection with 1 grasping spine, setose on palm, with distal shelf, with sinus, with distal palm projection; dactylus falcate. Gill 3 0.25 times corresponding pereonite length, straight. Pereopod 3 with 1 article, length 8 times width, with 8 distal and 1 lateral setae. Gill 4 0.25 times corresponding pereonite length, straight. Pereopod 4 with 1 article, length 5 times width, with 5 distal setae. Pereopod 5 merus shorter than basis length; carpus equal to basis length; propodus equal to basis length, with 1 pair of grasping spine at ¼ length of posterior margin; dactylus falcate. Pereopod 7 longer than pereopod 6, both longer than pereopod 5.

Pleon (based on male, 8.59 mm, AM P.100148). Uropod 1 bi-articulate; peduncle, length about 0.5 times width, with 3 lateral setae; ramus length about 5 times peduncular length, with 9 or 10 shorter setae. Telson (dorsal lobe) present with paired setae.

Female (based on paratype, 6.02 mm, AM P.100149). Head with paired anteriorly curved dorsal projections, with small subocular projection; eye large, distinctive. Antenna 1 slender, 0.85 times body length; peduncle article 2 longest; flagellum longer than peduncular length, with + 17 articles. Pereonite 2 with 2 small anterolateral projections, with paired anteriorly curved mid-dorsal projections, with curved dorsodistal projection. Pereonite 3 with small anterolateral projection, with midlateral projection, with paired anteriorly curved mid-dorsal projections, with dorsodistal projection. Pereonite 4 small with anterolateral projection, with dorsolateral projection. Pereonite 5 with 2 small anterolateral projections. Pereonites 6 and 7 not articulated obliquely. Gnathopod 2 inserting at anterior margin of corresponding pereonite; coxa vestigial; basis 0.8 times length of pereonite 2, with triangular projection; propodus subovate.

Remarks. During a field survey of One Tree Island, southern Great Barrier Reef in October–November, 2006, Circum-Australian Amphipod Project, Metaprotella were collected from the outer reef of One Tree Island lagoon at around 15 m depth. The Metaprotella from One Tree Island closely resembles but clearly differs from M. sandalensis [sensu stricto] ( Lim & Takeuchi, 2012) or other members of the M. sandalensis complex, justifying its establishment as a new species, Metaprotella lowryi sp. nov. Metaprotella lowryi differs from M. sandalensis in the following characteristics: (1) antenna 1 is 0.6 times body length (versus 0.8 times body length in M. sandalensis ); (2) antenna 1 peduncle article 3 is shorter than article 2 (versus longer than article 2 in M. sandalensis ); (3) the gnathopod 2 propodus palm lacks serratiform teeth (present in M. sandalensis ); (4) the dorsodistal projection of both pereonites 2 and 3 is more anteriorly curved in M. sandalensis than in M. lowryi .

Metaprotella lowryi is also close to M. solitaria Takeuchi & Lowry, 2017 (type locality: Solitary Islands, New South Wales). The new species differs from M. solitaria by the following characteristics; (1) the paired dorsal projections of the head are anteriorly curved (versus straight in M. solitaria ); (2) the gnathopod 2 propodus palm has a small distal shelf with sinus and distal palm projection, distinctly developed in the larger male (AM P.100148) (versus two distal palm projections in M. solitaria ); (3) mid-dorsal projections of pereonite 3 are anteriorly curved (versus straight in M. solitaria ); (4) dorsodistal projection of pereonite 3 is anteriorly curved (versus dorsally directed in M. solitaria ); and (5) pereonite 5 is longer than pereonite 4 (versus shorter in M. solitaria ).

Figures

Figure 1. Metaprotella lowryi sp. nov., holotype male, 7.08 mm, AM P.100147, and paratype female, 6.02 mm, AM P.100149, One Tree Island, Great Barrier Reef, Queensland, Australia, 23°29'05"S 152°04'07"E. Scale 1.0 mm.

Figure 2. Metaprotella lowryi sp. nov., holotype male, 7.08 mm,AM P.100147, One Tree Island, southern Great Barrier Reef, Queensland, Australia, 23°29'05"S 152°04'07"E. L, left; LL, lower lip; MD, mandible; MX, maxilla, MXP, maxilliped; R, right, and UL, upper lip. Scale = 0.05 mm.

Figure 3. Metaprotella lowryi sp. nov.: One Tree Island, southern Great Barrier Reef, Queensland, Australia, 23°29'05"S 152°04'07"E: A2, G1, G2 (M), P3–P7, holotype male, 7.08 mm, AM P.100147; G2 (M*), AB, paratype male, 8.59 mm,AM P.100148; G2 (F), paratype female, 6.02 mm,AM P.100149.A2, antenna 2; AB, abdomen; F, female; G1, gnathopod 1; G2, gnathopod 2; M, male; P3–P7, pereopod 1 to pereopod 7, respectively. Scale: G1, P3, P4, and AB = 0.1 mm; 0.2 mm for all others.