Linguimaera leo, Krapp-Schickel, 2003

Krapp-Schickel, T., 2003, Linguimaera Pirlot, 1936 (Crustacea, Amphipoda, Melitidae), a valid genus, Memoirs of Museum Victoria 60 (2), pp. 257-283 : 272-276

Linguimaera leo sp. nov.

Figures 10–12

Maera mastersi . — Barnard, 1972a: 226–227, fig. 132.

(not Megamoera mastersii Haswell, 1879b: 265 , pl. 11 fig. 1)

Material examined. Holotype. Australia. Victoria, Port Phillip Bay, Prince George Light (38˚6.3´S, 144˚44.25´E), 9.6 m, silty sand with broken rock, SCUBA, Fisheries and Wildlife Dept and Museum , (stn PPS 10), NMV J35851 (1 male 12 mm).

Paratypes. Collected with holotype NMV J52309 (1 male, 2 juveniles, 11.8, 6-7 mm). Vic., Portland Bay , reef below lighthouse (38˚22´S, 141˚36.2´E), 3 m, sand and rubble, SCUBA airlift, R.S. Wilson, 26 Feb 1992 (stn CRUST 141); NMV J24121 (1 female, 15 mm). Western Port, off Crib Point (38˚20.83´S, 145˚13.49´E), 13 m, sandy gravel, Smith-McIntyre grab, A.J. Gilmour on FV Melita , 23 Mar 1965 (stn CPBS-N 32); NMV J48856 (more than 20 males, females) .

Other material. Numerous specimens in 61 NMV collections from Vic. (Western Port, Port Phillip Bay , Cheviot Beach , Point Nepean , Bass Strait ) and SA (Cape Northumberland, Wallaroo ), 0–26 m, algal and sedimentary substrates. Port Phillip Bay (stn PPS 47 Area 40), USNM 275759 (1 male 12 mm, 1 female 10.5 mm, 2 male?juvenile 10 mm); (stn PPS 83 Area 69), USNM 275759 (6 males 8–10.5 mm, 3 females, 7.5–8 mm) .

Diagnosis. Gnathopod 1 propodus rectangular, ratio length: width = 2. Gnathopod 2 of male adult with prominent stout hump on palmar-corner, distally followed by a small incision; palm convex, with 3 incisions; dactylus near insertion not fitting totally to palm, leaving a hole-shaped gap. Pereopod 7 basis ratio length: width = 1.45. Telson with 1 long distal robust seta, between half and total telson length, and 3 short ones. (Pereopods 5–7 of ov. female strikingly twisted in articulation between merus and ischium.)

Description. Adult female 8–15 mm, male 7–12 mm.

Head nearly as long as first 2 segments, anteroventral corner acute. Eyes medially narrowed.

Antenna 1 about three fifths of body, peduncle article 1 subequal to article 2; flagellum of up to 30 articles, accessory flagellum of 3 or 4 articles; antenna 2 gland cone reaching half of article 3; flagellum of about 12 articles.

Mandible incisor, lacinia mobilis and molar medium; ratio palp article 2: article 1 = 3; article 2: article 3= 1.8; palp article 2 densely setose with 5–6 groups. Maxilla 1 inner plate narrower than outer plate, oval, with 3 plumose robust setae; outer plate 6 simple to pectinate robust setae, about twice as long as large, palp article 1 quadrangular, article 2 twice as long as large, 8 robust setae only apically. Maxilla 2 outer and inner plates equal, robust setae only dis-tally, no fine hairs marginally. Maxilliped inner plate reaching one third of palp article 2, apically truncate with dense distal and a few lateral robust setae; outer plate large, oval, reaching two thirds of article 2 of palp, with curved robust setae, gradually increasing in length from inner to outer side; palp article 1 shorter than one third of article 2, article 3 half article 2, oval.

Gnathopod 1 not sexually dimorphic; coxa 1 anteriorly acutely lengthened; basis anterior margin with 4 or 5 medial robust setae, posteriorly longer robust setae; merus posteroventrally with short tooth; carpus regularly rounded on both margins, with stiff marginal and submarginal robust setae, about twice as long as wide; propodus rectangular, less broadened than carpus, ratio length: breadth = 2, palm oblique, well defined by blunt corner.

Gnathopod 2 of female strongly dimorphic in size, similar in shape; merus posterodistally with blunt tooth; carpus posteroventral corner with sharp tooth; carpus: propodus = 2:3, about same width; propodus rectangular, twice as long as wide, palm scarcely concave, scarcely defined by corner, no posterodistal “thumb”; 1 subdistal prominent robust seta on inner surface next to palmar corner, 6 smaller ones along palm. Gnathopod 2 of male strongly dimorphic in size and shape: the smaller is as described for smaller female gnathopod 2, the other has a palmar corner defined by a blunt and prominent “thumb”, distally followed by a short excavation, palm with rounded hump having 3 short excavations; dactylus strongly curved, leaving a hole-shaped gap near insertion.

Pereopods 3, 4 shape very similar, pereopod 3 reaching distally about half of gnathopod 2 propodus. Pereopods 5–7 similar, very spinose, on both margins serrate, propodus equal to merus, carpus shorter, basis: propodus = 1.7; pereopod 5 basis posterior margin straight to concave and weakly serrate, posterodistal corner broadened and lengthened; pereopod 6 subequal or somewhat longer pereopod 7, posteroventral corner lengthened.

Uropods 1, 2 ending at similar level; uropod 2 inner margin with 2 strong robust setae; uropod 3 peduncle half length of rami, outer ramus narrower than inner one; distally clearly truncate, with marginal robust setae on outer ramus in 7 or 8 groups.

Epimeral plate 3 serration with 7 or 8 teeth.

Telson quadrangular, 1 or 2 setae and no or 1 strong robust seta marginally; each lobe distally excavated as U-shape, with outer corner acutely prominent; in excavation 1 long robust seta (half or more telson-length) and 3 additional ones, not much surpassing length of the sinus.

Etymology. Dedicated to little Leo, the “most beautiful grandson in the world”! (noun in apposition).

Distribution. Victoria (Port Phillip Bay, Western Port, Portland Bay), South Australia (Wallaroo), Western Australia (Bunbury, Favourite Is, Point Peron) (J.L. Barnard, 1972a); littoral, gravel pools, under rocks and holdfasts on reef, sand and rubble, sandy gravel; occurred in 56 samples with depth average of 12 m; most robust adults in intertidal.

Remarks. Already Barnard (1972a: 226) noticed the somewhat “disproportionate” insertion between propodus and carpus of gnathopod 1, which leads to a deeper “gap” dorsally.

Discussion. This species is found sometimes together with L. tias sp. nov. and has for more than a century been mixed up with other similar species. The above cited bibliography therefore contains only the proven citation by Barnard (1972a). There are several records of “ M. mastersi (Haswell) ”, mainly by Chevreux (1908: 481 – French Polynesia); Stebbing (1910: 457 – South Africa); Chilton (1916: 367 – New Zealand); Chilton (1925: 317 – Chatham Islands, New Zealand). But there is not enough information to make a conclusion.

Figures

Figure 10. Linguimaera leo sp. nov., male, female (Victoria, Port Phillip Bay). Gn1 female in scale x = 1 mm, all other in scale y = 1 mm.

Figure 11. Linguimaera leo sp. nov., male, female (Victoria, Port Phillip Bay). Gn1 male, Gn2s male, Gn2 l large male, female, Gn2 male hyperadult, Gn2 small female in scale x = 1 mm; Gn1´male, Gn2´small male, Gn2´large, Gn2´small female in scale y = 1 mm.

Figure 12. Linguimaera leo sp. nov., male, female (Victoria, Port Phillip Bay). P3–7 female, P7´, P7 hyperadult male, U1 in scale x = 1 mm; Ep3, U3 male, female, P7´´ male, T male, female in scale y = 1 mm.