Leydigia (Neoleydigia), 2009

Kotov, Alexey A., 2009, A revision of Leydigia Kurz, 1875 (Anomopoda, Cladocera, Branchiopoda), and subgeneric differentiation within the genus, Zootaxa 2082 (1), pp. 1-84 : 42-43

VI. Leydigia (Neoleydigia) sp. nov.

Leydigia acanthocercoides ( Fischer, 1854) in Alonso 1996, p. 361 –363, figs. 161–162.

Material examined. According to published description.

Diagnosis. Parthenogenetic female. Body subovoid, maximum height in midlle, dorsal margin slightly convex in posterior part, postero-dorsal angle well-defined. Coarse striation on valves probably absent, a fine striation present. Head small, compound eye and ocellus subequal in size. PP = 5–6 IP, lateral head pores about 0.6 IP distance from midline. Labral keel subtriangular, its posterior margin with a few tufts of setules, anterior margin with long fringe of setules up to apex, also several lateral groups of relatively long setules on sides of keel. On valves, setae at middle of ventral margin with short setulation, probably no setules between their bases. Submarginal setules of whole posterior margin fine, not organized into groups. Marginal membrane not described.

Postabdomen subovoid, robust, with slightly convex ventral margin, preanal margin somewhat shorter than anus, in general straight, with numerous small hillocks, preanal and postanal angles well defined, neither distal margin nor dorso-distal angle on postabdomen. Postanal marginal denticles in about 24 clusters, about 4 series of marginal setules on anal margin. About 10 fascicles of stout lateral setae, 3–4 per each fascicle, two marginalmost setae of each fascicle subequal in size, other setae much shorter. About 22 fascicles of lateral setules on basal half of postanal and anal margin. Postabdominal claw robust, almost straight, no basal spine.

Antenna I elongate, not reaching tip of rostrum, with 3 (?) transverse rows of long setules on anterior face, probably no setules at its end; sensory seta particularly long, arising at distance of 1/5–1/6 of appendage length from distal end. Largest aesthetasc about half as long as appendage, slightly protruding behind tip of rostrum. Antenna II with 3 relatively short and stout spine-like setules on first, and 3 of these setules on second endopod segment. Basal and distal lateral seta unequal in size, both shorter than apical setae.

Trunk limb I with ODL large, cylindrical, with scattered fine setules and long seta with unilaterally setulated distal segment, IDL with 3 marginal clusters of long setules, first seta small, with a numerous, relatively long setules distally; second and third setae subequal in length, but with different setulation, endite 3 with a long seta 1, endite 2 with two long soft setae unequal in length, seta 2 short. Two ejector hooks unequal in size. On trunk limb II, distalmost scraper with fully setulated basal segment, on distal lobe with basal tuft of long setules. Trunk limb III exopodite trapezium-shaped, with five setae (or more, rudimentary setae can be missed); seta 2 with distal segment setulated bilaterally with short setules (there are traces of their alternation in size in Fig. 162D in Alonso, 1996), setae 3–5 relatively short, in filter plate basalmost and distalmost setae shorter than rest. Trunk limb IV with subovoid exopodite, setae 2 relatively long, seta 1 short, both armed with long, fine setules. Inner face of limb V, two setulated setae of subequal length, basalmost markedly slender, distal armature of gnathobase a setulated lobe, 'filter plate' with two small setae.

Ephippial female. Not described by Alonso (1996) in detail, only an un-remarkable ephippium pictured.

Adult male. Unknown.

Size. Parthenogenetic female up to 1000 µm.

Differential diagnosis. This species has a series of traits rarely observed in well-studied species of the subgenus L. (Neoleydigia), and never in this combination: (1) PP distance large; (2) numerous, low hillocks on preanal margin of postabdomen; (3) numerous setae in lateral fascicles on postabdomen, plus distalmost and next setae subequal in size; (4) sensory seta shifted to distal end of antenna I, but not so markedly as in L. microps ; (5) fully setulated basal segment of distalmost scraper on limb III; (6) 5 (or perhaps more) setae on exopodite III.

Taxonomic comments. This form was described in detail by Alonso (1996) as L. acanthocercoides from "la laguna Longuilla (Sevilla)", Spain. The determination was based predominantly on the absence of a basal spine on the postabdominal claws. Obviously, this species is not L. acanthocercoides , and even not a member of the L. acanthocercoides -group. Some characters must be re-examined, but there is no doubt that this is a undescribed species. Among previously described formal species, no similar taxa were found. It will be described as a new species by Dr M. Alonso in a future publication.

Distribution. Known only from a locality in Seville. Previous records of L. acanthocercoides from the Iberian Peninsula may also refer to this species.

Figures

FIGURES 162–168. Leydigia microps, lectotype (162–165) and paralectotype (166–168), parthenogenetic females from slide GOS F 9223, from Green Point Common, Republic of South Africa. 162, 166. General view. 163, 167. Head. 164–165, 168. Postabdomen. Scale bar denotes 100 µm.