Limnoria turae, Castelló, 2011

Castelló, José, 2011, The genus Limnoria (Limnoriidae, Isopoda, Crustacea) in Europe, including a key to species, Zootaxa 2968 (1), pp. 1-25 : 2-6

Limnoria turae n. sp.

( Figs 1–3 )

Limnoria quadripunctata . Castelló, 1986; Junoy & Castelló, 2003.

Material examined. Holotype, adult non-ovigerous female [A] (4.1 mm length ( MNCN 20.04 /8599), Fauna IV expedition, 25.07.96, collected on Laminaria ochroleuca , with 25 slides ( MNCN 20.04 /8574–8598)) . Paratypes (same data as holotype): male (2.5 mm length ( MNCN 20.04 /8656), with 27 slides ( MNCN 20.04 /8629–8655)); ovigerous female [B] (3.8 mm length ( MNCN 20.04 /8627), with 27 slides ( MNCN 20.04 /8600–8626); also used for SEM examination); non-ovigerous female [C] (3.2 mm length ( MNCN 20.04 /8628), used for SEM examination); juvenile (1.5 mm length ( MNCN 20.04 /8663), with 6 slides ( MNCN 20.03 /8657–8662)) . Other material: male (2.4 mm length, with 25 slides; also used for SEM examination) (2011-0233 MZB, Cap d'Artrutx, Menorca), non-ovigerous female 0.8 mm pleotelson width (used for SEM examination) (2011-0234 MZB, Cap d'Artrutx, Menorca), male (2.6 mm length, with 22 slides) (2011-0236 MZB, Cap de Cavalleria , Menorca), non–ovigerous female [A] 2.5 mm length (used for SEM examination) (2011-0238 MZB, Cap de Cavalleria, Menorca), non–ovigerous female [B] 1.5 mm length (used for SEM examination) (2011-0237 MZB, Cap de Cavalleria, Menorca), male (2.5 mm length, with 25 slides; also used for SEM examination) with tegument damaged on the distal section of pleotelson (2011-0239 MZB, Portinatx, Ibiza) .

Type locality. East of Alborán Island (off Almería); coordinates: latitude 35º 58'00”N , longitude 02º58' 27”W; 36 m depth.

Etymology. The species is dedicated to my wife, Nieves Tur.

Diagnosis. Mandibles lacking rasp. Posterior pleotelsonic margin with stout unsheathed setae, sheathed setae, and scale spikes; dorsally with row of short blunt scale spikes in clusters of 4–8. Pleonite 5 with dorsal Y-shaped carina, without tubercles. Pleotelsonic sculpture with three pairs of carinae without tubercles, the central pair being the longest. Tegument pitted and extremely setose on pleonite 5 and anterior section of pleotelson. Substrate seaweed, not wood.

Description of the female holotype (MNCN 20.04/8599, 8574–8598).

Antenna 1 with 4 flagellar articles; second article with 5 aesthetascs. Flagellum of antenna 2 with 4 articles.

Mandibular palp with 3 articles; proximal article with 1 apical seta; second article with 1 apical seta and 3–4 plumose setae; distal article with 5–6 plumose setae. Mandibular incisors without rasp; file present. Lacinia mobilis of right mandible long and enlarged apically trifid, with several apical teeth. Epipod of maxilliped triangulate 4 times as long as wide, not reaching articulation of palp articles 1 and 2; epipod with 2–3 simple setae.

Pereopod 1 with secondary unguis bifid. Ventral comb setae present on merus of pereopod 7 and carpus of pereopods 6 and 7.

Pleopod 2 with plumose setae up to 0.6 times length of exopod. Endopod of pleopod 5 anterior to exopod, oval, 0.8 times as long as endopod of pleopod 2; peduncle of pleopod 5 with simple seta laterally.

Uropod peduncle without lateral prominent tubercles; endopod without tubercles, 0.7 times as long as peduncle; scale spikes on both peduncle and endopod.

Male paratype MNCN 20.04 /8656: Appendix masculina long, reaching beyond endopod tip, articulating proximal to 43% of length of endopod. Endopod with 7 setae; exopod with 17 setae. Plumose setae up to 0.6 length of exopod .

Additional characters: Tegument deeply pitted, with crests, especially in the anterior section of pleotelson, scalloped in the distal area. Pleonite 5 0.6 length of pleotelson.

Variation. Second article of antenna 1 with 7 aesthetascs in ovigerous female [B] paratype MNCN 20.04 / 8627, 3 in male paratype MNCN 20.04 / 8656, and only 1 in juvenile paratype MNCN 20.04 / 8663. Distal article of mandibular palp with 8 plumose setae in ovigerous female [B] paratype MNCN 20.04 / 8627, and 4 in male paratype MNCN 20.04 / 8656. Secondary unguis of pereopod 7 bifid in ovigerous female [B] paratype MNCN 20.04 /8627.

Distribution. Alborán Island, and Balearic Islands (Western Mediterranean).

Remarks. Table 2 shows the features of all the specimens studied. The erection of new species of Limnoria seems to be made on the basis of features that may show a considerable degree of variability. For example, in the European species the number of flagellar articles varies between 4 and 5, also in the same species (males of L. mazzellae had one flagellum with 4 articles and the other one with 5); the dorsal sculpture of pleotelson also varies in some populations, as pointed out by Cookson (1991) in the case of L. tuberculata ; and the ventral comb setae on the carpus of pereopods 2 and 3 may be absent in some populations of L. quadripunctata ( Cookson, 1991) . Nevertheless, the different species can be distinguished if a series of characters are combined: for example the number of aesthetascs of antenna 1, the number of flagellar articles of antenna 2, the mandible, the shape and size of maxillipedal epipod, the setation of pereopods 1–7, the shape and size of appendix masculina, the shape of the endopod of pleopod 5, the uropod, and the sculpture of pleonite 5 and the pleotelson; these features are shown in detail for the European species in Table 1.

L. turae n. sp. is closely related to L. carinata , and L. lignorum in having 4 flagellar articles of antenna 2, and differs from L. quadripunctata , L. tripunctata , and L. tuberculata (5 flagellar articles). The maxillipedal epipod of L. turae n. sp. is triangulate, as in the remaining European species. L. turae n. sp. lacks ventral comb setae on carpus of pereopods 2–5, which are present in L. lignorum , L. mazellae , L. quadripunctata , and L. tripunctata , and resembles L. carinata , L. lignorum , L. mazzellae , L. tripunctata and L. tuberculata in having pereopod 7 with ventral comb seta on merus. The uropodal peduncle of L. turae n. sp. is smooth (vs. tuberculate in L. lignorum , L. mazzellae , L. tripunctata , and L. tuberculata ). The dorsal sculpture of pleonite 5 of L. turae n. sp. has a Y–shaped carina, without tubercles, as in L. carinata . The pleotelsonic sculpture of L. turae n. sp. is unique among the European species: 3 pairs of longitudinal carinae without puncta. With regard to the posterior margin of pleotelson, L. turae n. sp. shows 4 stout unsheathed setae, sheathed setae, and scale spikes, as in L. carinata , and L. quadripunctata ; however there is a dorsal row of short blunt scale spikes in clusters of 4–8 on the posterior and lateral perimeter of the pleotelson (stouter and arranged in various rows on the lateral margins) in L. turae n. sp. (vs. single scale spikes in L. carinata , and L. quadripunctata ). The most important difference with respect to the remaining species is the lack of the mandibular rasp. Regarding ecology, L. turae n. sp. was caught on the sedimentary bottom with algae ( Laminaria ) while the remaining European species are wood boring (except L. mazzellae which bores into Posidonia seagrass). In addition, the dissected specimens of L. turae n. sp. have shown numerous strands of filamentous algae on the pereopods and on the mouthparts, especially maxillipeds, which is typical of algal borers.

Figures

FIGURE 1. Limnoria turae n. sp. Holotype female [A], MNCN 20.04/8599. A, schematic figure of pleotelson. B, antenna 1. C, antenna 2. D, left mandible. E, right mandible. F, maxilla 1. G, maxilla 2. H, maxilliped. Scale bars: A = 0.5 mm, B–E, H = 0.1 mm, F–G = 0.05 mm.

FIGURE 2. Limnoria turae n. sp. Holotype female [A], MNCN 20.04/8599. A, pereopod 1. B, pereopod 3. C, pereopod 5. D, pereopod 7. Scale bar: A–D = 0.1 mm.

FIGURE 3. Limnoria turae n. sp. Holotype female [A], MNCN 20.04/8599. A, pleopod 1. B, pleopod 2. C, pleopod 3. D, pleopod 4. E, pleopod 5. F, uropod. Paratype male, MNCN 20.04/8656. G, antenna 1. H, pleopod 2. I, uropod. Male, 2011-0233 MZB. J, antenna 1. K, left mandible. L, right mandible. M, pleopod 2. N, uropod. Scale bars: A–D = 0.25 mm, E–N = 0.1 mm.