Linguimaera mere, Hughes, Lauren E., 2016

Hughes, Lauren E., 2016, New genera, species and records of Maeridae from Australian Waters: Austromaera, Ceradocus, Glossomaera, Hamimaera, Huonella gen. nov., Linguimaera and Maeraceterus gen. nov. (Crustacea: Amphipoda), Zootaxa 4115 (1), pp. 1-81 : 60-65

Linguimaera mere sp. nov.

( Figs 49–53 )

Type material. Norfolk Island: Holoytpe male, 12 mm, dissected, 4 slides, AM P.92511, near Anson Point, Gun Club Reef (29°00′25″S 167°54′45″E), 14.6 m, coral rubble on sand, 17 May 2008, coll. R.T. Springthorpe (MI NFK 62) ; Paratype 1 specimen, AM P.81537 near Anson Point , Gun Club Reef (29°00′25″S 167°54′45″E), 14.6 m, coral rubble on sand, 17 May 2008, coll. R.T. Springthorpe (MI NFK 62) ; Paratypes 2 specimens, AM P.81530, East of Sail Rock , Phillip Island (29°06′55″S 167°57′31″E), 14.8 m, under stones, rubble, 14 May 2008, coll. R.T. Springthorpe (MI NFK 20) ; paratype b male, 8.8 mm, dissected, 4 slides, AM P.92531, Emily Bay , Norfolk Island (29°03′36″S 167°57′12″E), 3.7 m, rubble on sand, 20 May 2008, coll. R.T. Springthorpe (MI NFK 82) ; Paratype 1 A female, AM P.81538, dissected, 4 slides, Emily Bay , Norfolk Island (29°03′36″S 167°57′12″E), 4 m, tubes and rubble with encrusting algae, 20 May 2008, coll. J.K. Lowry (MI NFK 87) ; Paratypes 3 specimens, AM P.81543, Emily Bay , Norfolk Island (29°03′36″S 167°57′12″E), 3.7 m, rubble on sand, 20 May 2008, coll. R.T. Springthorpe (MI NFK 82) ; Paratype 1 specimen, AM P.81541, Emily Bay , Norfolk Island (29°03′36″S 167°57′12″E), 3.7 m, rubble and algae, 20 May 2008, coll. R.T. Springthorpe (MI NFK 84) ; Paratype 1 specimen, AM P.81540, Swiss Cheese Reef , Norfolk Island (29°00′23″S 167°56′50″E), 16.6 m, coral rubble, 15 May 2008, coll. R.T. Springthorpe (MI NFK 36) ; Paratypes 3 specimens, AM P.81542, Fig Valley Reef (29°03′20″S 167°55′44″E), 18.5 m, coral rubble with algal tufts and sediment, 19 May 2008, coll. R.T. Springthorpe (MI NFK 67) ; Paratypes 10 specimens, AM P.81531, Fig Valley Reef (29°03′20″S 167°55′44″E), 18.5 m, coral rubble with algal tufts and sediment, 19 May 2008, coll. R.T. Springthorpe (MI NFK 67) ; Paratypes 3 specimens, AM P.81532, Emily Bay (29°03′36″S 167°57′12″E), 3.7 m, rubble on sand, 20 May 2008, coll. R.T. Springthorpe (MI NFK 82) ; Paratype 1 specimen, AM P.81533, Cathedral Rock (29°00′13″S 167°56′57″E), 10.7 m, sediment and algae from rock face, 13 May 2008, coll. R.T. Springthorpe (MI NFK 8) ; Paratypes many specimens, AM P.81535, East of Sail Rock , Phillip Island (29°06′55″S 167°57′31″E), 13 m, under stones, 14 May 2008, coll. R.T. Springthorpe (MI NFK 22) ; Paratypes 2 specimens AM P. 81544, Cathedral Rock (29°00′13″S 167°56′57″E), 10.9 m, under stones, 13 May 2008, coll. R.T. Springthorpe (MI NFK 7) ; Paratypes 3 specimens, AM P. 81545, Fig Valley Reef (29°03′20″S 167°55′44″E), 19.7 m, near limestone reef sediment and some algae, 19 May 2008, coll. R.T. Springthorpe (MI NFK 65) ; Paratype 1 male, AM P.81536, Phillip Island, Cow Bay (29°00′10″S 167°57′03″E), 12 m, red and brown algae on rocks, 14 May 2008, coll. L.E. Hughes (MI NFK 32).

Type locality. near Anson Point , Gun Club Reef, Norfolk Island, South Pacific (29°00′25″S 167°54′45″E). Etymology. Tahitian for club, in reference to the male dominant gnathopod 2.

Description. Based on holotype male, 12 mm, AM P.92511.

Head. Eyes subovate; lateral cephalic lobe broad, rounded, apically truncate, anteroventral margin with notch/ slit, anteroventral corner rounded. Antenna 1 longer than antenna 2; peduncular article 1 shorter than article 2, with 1 robust seta on posterior margin; peduncular article 2 longer than article 3; flagellum articles as long as broad, or broader than long, with more than 18 articles; accessory flagellum short, significantly less than half length of primary flagellum, with 7 articles. Antenna 2 peduncular article 4 longer in length than article 5; flagellum with 11 articles. Mandible accessory setal row, well developed with 7 setae; palp well developed, article 1 length 2 × width, shorter than article 2; article 2 longer than article 3, with many slender setae; article 3 rectilinear, long, 3.8 × as long as broad, longer than article 1, with 5 apical slender setae. Lower lip without apical ducts, mandibular lobes apically rounded. Maxilla 1 inner plate subquadrate, with 3 apical plumose setae (article folded on slide, not illustrated).

Pereon. Gnathopod 1 coxa anterior margin concave, anteroventral corner produced, acute, posteroventral corner with notch; merus with acute posteroventral corner; carpus length 2.6 × width, 1.1 × propodus length, setae covering medial surface; propodus rectilinear, medial surface setal comb absent; palm subacute, straight, entire, lined with robust setae, weakly defined by posterodistal corner; dactylus closing along palm.

Gnathopod 2 asymmetrical; larger gnathopod, subchelate; coxa posteroventral corner without notch; basis slender, anterior margin lined with long robust setae, anterodistal corner subquadrate; merus with acute posteroventral corner; carpus compressed, length subequal to width, anterior margin with a few slender setae; propodus rectilinear, length 2.1 × width, margin with rows of short slender setae, palm angle subacute, distal shelf with 3 pairs of long robust setae, margin smooth, palm defined by posteroventral corner with tooth, without long robust seta; dactylus short, closing short of palm, reaching 0.5 of palm length, unguis absent. Gnathopod 2 smaller gnathopod basis slender, anterior margin smooth, anterodistal corner subquadrate; merus with acute posteroventral corner; carpus subtriangular, length 1.9 × width, margins with long slender setae; propodus rectilinear, length 2.2 × width, margin with rows of long slender setae, palm angle acute, margin straight, lined with robust setae, without palm defining corner; dactylus closing along and reaching end of palm, posterior margin lined with setules, unguis present.

Pereopods 5–7 slender distally; basis posterior margin straight, serrate, with a few long setae; merus and carpus not broadened; dactylus unguis simple.

Pleon. Pleonites 1–3 dorsally smooth. Epimeron 1 posterodistal corner with notch. Epimeron 2 posterior margin with a few distal serrations, posterodistal corner with notch. Epimeron 3 posterior margin serrate along length. Urosomites 1–3 without carina. Uropod 1 peduncle with 1 basofacial seta, peduncle length 1.5 × outer ramus; inner ramus longer than outer ramus. Uropod 2 peduncle length subequal to outer ramus; inner ramus longer than outer ramus. Uropod 3 unknown. Telson deeply cleft, length subequal to width, lobes divergent, tapering distally, with longer outer and shorter inner cusps, apically acute, margins concave, each lobe with 2 short and 1 long apical robust setae, without marginal or lateral robust setae.

Variation. The asymmetric gnathopod 2 may be left or right dominant (lot AM P. 815423 has specimens of both examples). Juvenile male specimens, 8.8 mm, the robust setae have not developed along the basis (AM. P.92531, Figure 52 ). In larger, 11–12 mm, male specimens the gnathopod 2 dactylus shortens and becomes more broad ( Figure 52 ).

Remarks. Linguimaera mere sp. nov. is similar to L. boecki and L. boeckoides sp. nov. in the large male gnathopod 2 with rectilinear propodus defined by a subacute tooth. The deep subquadrate palmar excavation distinguishes L. mere sp. nov. from the later species, along with the row of robust setae along the basis anterior margin. Linguimaera mere sp. nov. is also similar L. kellissa which has a gnathopod 2 palmar excavation, the presence of lateral robust setae on the telson separates this species from L. mere sp. nov.

Distribution. Tasman Sea: Norfolk Island (current study).

Linguimaera sp. ( Fig. 54 )

Material examined. Cocos (Keeling) Islands. Male , 5.8 mm, AM P.81808, coral bommie near wreck of the Catalina , near Horsburgh Island, Cocos (Keeling) Islands (12°05′48″S 96°51′31″E), 7.2 m, rubble and sand under stones, 9 October 2008, coll. K.B. Attwood (MI WA 794).

Remarks. This species is similar to L. mere sp. nov. based on the male gnathopod 2. The single specimen form Cocos (Keeling) Island has a pair of lateral robust setae of the telson , which is absent in L. mere sp. nov. The uropod 3 is missing in the specimen, which makes comparison difficult for this otherwise closely related species. Given the large geographic distance between Cocos (Keeling) Islands in the Indian Ocean and Norfolk Island, South Pacific as the type locality of L. mere , the identity of this specimen remains ambiguous until more material becomes available. Other species of Linguimaera , L. gartima and L. leo , are similarly separated by characters including the single pair of lateral robust setae on the telson . However more complete specimens and multiple lots of study material were able to confirm the stability of these subtle differences.

Distribution. Indian Ocean. Cocos (Keeling) Islands (current study).

Figures

FIGURE 49. Linguimaera mere sp. nov., holotype male, 12 mm, AM P. 92511, Gun Club Reef, Norfolk Island, scales 0.1 mm.

FIGURE 50. Linguimaera mere sp. nov., holotype male, 12 mm, AM P. 92511, Gun Club Reef; Norfolk Island, scales 0.1 mm.

FIGURE 51. Linguimaera mere sp. nov., holotype male, 12 mm, AM P. 92511, Gun Club Reef; * male (partial specimen), AM P. 81543; ** male, 8 mm, AM P. 81536; *** male, 11.8 mm, AM P. 81530, Norfolk Island, scales 0.1 mm.

FIGURE 52. Linguimaera mere sp. nov., male, 8.8 mm, AM P. 92531, Emily Bay, Norfolk Island, scales 0.1 mm.

FIGURE 53. Linguimaera mere, male, 12 mm, AM P. 92511, Gun Club Reef; * male, 8.8 mm, AM P. 92531, Emily Bay, Norfolk Island, scales 0.1 mm.

FIGURE 54. Linguimaera sp., male, habitus 5.8 mm, AM P. 81808, Horsburgh Island, Cocos (Keeling) Islands, scales 0.1 mm.