Linguimaera christorei, Hughes, 2015

Hughes, L. E., 2015, Ampithoidae and Maeridae Amphipods from Timor-Leste (Crustacea: Peracarida), Records of the Australian Museum 67 (3), pp. 83-108 : 95-97

Linguimaera christorei sp. nov.

Figs 13–15

Type material. Holotype male, 5.0 mm, dissected, 5 slides, AM P. 90576, 300 m off Jesus Backside Beach, east of Cape Fatucama (8°31'16" S 125°36'46" E), 12–15 m, dead coral rubble with epiphytic growth and sponges, coll. A. Murray, P.A. Hutchings, L.E. Hughes & A. Reid, 19 September 2012 ( TM 2012-014); paratype female, 5.0 mm, AM P.90564, south side off Christo Rei Beach, east of Dili (8°31'46" S 125°36'21" E), 5–10 m, coral slope, dead coral rubble, coll. L.E. Hughes, 23 September 2012 ( TM 2012-088); paratype female, AM P. 90565, 300 m off Jesus Backside Beach, east of Cape Fatucama (8°31'16" S 125°36'46" E), 12–15 m, dead coral rubble with epiphytic growth and sponges, coll. A. Murray, P.A. Hutchings, L.E. Hughes & A. Reid, 19 September 2012 ( TM 2012-014) .

Type locality. 300 m off Jesus Backside Beach, east of Cape Fatucama, Timor-Leste (8°31'16" S 125°36'46" E) .

Etymology. Named for the statue which overlooks the type locality.

Diagnosis. Antenna 1 peduncular article 1 with 1 robust seta on posterior margin; accessory flagellum short, with 4 articles. Antenna 2 peduncular article 2 cone gland not reaching to end of peduncular article 3; peduncular article

4 longer in length than article 5. Mandible accessory setal row with 4 setae; Maxilla 1 inner plate with 3 plumose setae; outer plate palp article 2 slender with apical fine setae only. Gnathopod 2 significantly enlarged in male, not in female, left and right gnathopods unequal in size. Gnathopod 2 larger gnathopod; propodus anterior and posterior margins with rows of long slender comb setae, propodus palm subacute, straight, distal shelf with group of 6 robust setae, with 2 evenly spaced subacute teeth, palm margin with sparse robust setae, posterodistal corner produced, straight, defined by tooth, with robust seta; dactylus closing along and reaching end of palm, with anterior margin with slender seta, posterior margin smooth, apically acute. Gnathopod 2 smaller gnathopod subchelate; merus with acute posteroventral corner; carpus long, length 1.1 times propodus. Pereopods 5–7 basis posterior margin straight, weakly serrate posteroventral corner subquadrate; carpus and propodus without long, slender setae along margins. Epimeron 2 posterior margin smooth, ventral margin smooth with 3 robust setae, posteroventral corner with notch. Epimeron 3 ventral margin smooth, with 2 robust setae, posteroventral corner serrate distally. Uropod 3 rami distally truncated, with long and short apical robust setae; inner ramus long, length 4 times breadth. Telson each lobe with subequal or longer outer apical cusps, apical margins concave, apical cusps subacute, reaching scarcely one third along longest seta, each lobe with 1 long apical robust seta, and 1 lateral short robust setae.

Description. Based on holotype male 5 mm, AM P.90576.

Head. Eyes well developed, reniform; lateral cephalic lobe broad, rounded, anteroventral margin with notch/slit, 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; primary flagellum articles as long as broad with 24 articles; accessory flagellum short, significantly less than half length of primary flagellum, with 4 articles. Antenna 2 peduncular article 2 cone gland not reaching to end of peduncular article 3; peduncular article 4 longer in length than article 5; flagellum with 8 articles. Mandible accessory setal row with 4 setae; molar enlarged; palp, well developed, 3-articulate; article 1 as long as broad, shorter than article 2, inner margin not produced distally; article 2 longer than article 3 with few slender setae; article 3 rectolinear, long, 3 times as long as broad, longer than article 1 with 4 subapical slender setae. Lower lip inner lobes present, outer lobes without ducts. Maxilla 1 inner plate with 3 plumose setae; outer plate palp article 2 slender with apical fine setae only.

Pereon. Gnathopod 1 coxa anterior margin concave, anteroventral corner produced, subacute, posteroventral corner with notch; merus without posterodistal tooth; carpus twice as long as broad, subequal in length to propodus, with a few slender setae; propodus palm subacute, convex, entire, defined by posterodistal corner with 1 robust seta. Gnathopod 2 sexually dimorphic, significantly enlarged in male, not in female, left and right gnathopods unequal in size. Gnathopod 2 larger gnathopod; subchelate; coxa posteroventral corner notched; basis slender, anterodistal

corner subquadrate; ischium without lobes; merus with subquadrate posteroventral corner; carpus compressed, length 0.2 times propodus; propodus subchelate, expanded, rectolinear, anterior and posterior margins with rows of long slender comb setae, propodus palm subacute, straight, distal shelf with group of 6 robust setae, with 2 evenly spaced subacute teeth, palm margin with sparse robust setae, posterodistal corner produced, straight, defined by tooth, with robust seta; dactylus closing along and reaching end of palm, with anterior margin with slender seta, posterior margin smooth, apically acute. Gnathopod 2 smaller gnathopod subchelate; merus with acute posteroventral corner; carpus long, length 1.1 times propodus; propodus linear, palm subacute, convex, defined by posteroventral corner, with 1 robust seta; dactylus closing along and reaching end of palm, anterior margin with 1 slender seta, apically subacute. Pereopods 3–7 dactylus without accessory posterodistal spine, ungues simple. Pereopods 5–7 basis posterior margin straight, weakly serrate posteroventral corner subquadrate; carpus and propodus without long, slender setae along margins.

Pleon. Pleonites 1–3 dorsally smooth. Epimeron 1 posterior and ventral margins smooth, posteroventral corner with notch. Epimeron 2 posterior margin smooth, with 2 robust setae ventral margin smooth with 3 robust setae, posteroventral corner with notch. Epimeron 3 ventral margin smooth, posteroventral corner serrate distally. Uropod 1 peduncle with 1 basofacial seta; rami slender, inner ramus slightly shorter than outer ramus. Uropod 2 rami slender, inner ramus slightly shorter than outer ramus. Uropod 3 rami

distally truncated, with long and short apical robust setae; inner ramus long, length 4 times breadth, much longer than peduncle, subequal in length to outer ramus. Telson longer than broad, deeply cleft (more than 66%), lobes divergent, tapering distally, each lobe with subequal or longer outer apical cusps, apical margins concave, apical cusps subacute, reaching scarcely one third along longest seta, each lobe with 1 long apical robust seta, and 1 lateral short robust seta.

Remarks. In Linguimaera christorei sp. nov. the larger male gnathopod 2 propodus palm has a distal shelf and two evenly spaced teeth which distinguish it from all other

Linguimaera species. Males of Linguimaera boecki Lowry & Springthorpe, 2005 and L. mannarensis Sivaprakasam, 1970 have a similar gnathopod 2 palm with two teeth but this differs in the shape and the position of the teeth.

Examination under high power compound microscope confirms that the setae projecting from the mandibular molar surface are attached and not a misinterpretation, these structures are unusual within the group. Limited material and damage during dissected prevented a more detailed inspection under a scanning microscope.

Distribution. Timor-Leste (current study).

Figures

Figure 13. Linguimaera christorei, sp. nov., holotype male, 5.0 mm, AM P.90576, east of Cape Fatucama, 300 m off Jesus Backside Beach.

Figure 14.Linguimaera christorei, sp.nov., holotype male, 5.0 mm,AM P.90576, east of Cape Fatucama, 300 m off Jesus Backside Beach, scales 0.1 mm.

Figure 15.Linguimaera christorei, sp.nov., holotype male, 5.0 mm,AM P.90576, east of Cape Fatucama, 300 m off Jesus Backside Beach, scales 0.1 mm.