Flavalona setigera ( Brehm, 1931 ) Sinev & Dumont, 2016

Sinev, Artem Y. & Dumont, Henri J., 2016, Revision of the costata-group of Alona s. lato (Cladocera: Anomopoda: Chydoridae) confirms its generic status, European Journal of Taxonomy 223, pp. 1-38 : 16-18

Flavalona setigera ( Brehm, 1931) comb. nov.

Fig. 3D

Alona guttata var. setigera Brehm, 1931: 499–501 , figs 5–7.

Biapertura setigera Smirnov & Timms, 1983: 58–59 , figs 67–68.

Biapertura rusticoides Smirnov & Timms, 1983: 64 , fig. 75.

Alona setigera Sinev, 1999a: 138–142 , figs 5–8.

non Alona setigera – Chen & Peng 1993: 19, figs 1–5.

Diagnosis

Female

Length 0.39–0.49 mm. Body regular oval, maximum height at mid-body, height/length ratio ca 0.6. Valves from previous molts not retained. Posteroventral angle without setules protruding beyong valve margins. Ventral margin with about 40 setae. Valves covered by thin, sparsely spaced longitudinal lines.

Eye larger than ocellus. Rostrum short, broadly rounded. Posterior margin of head shield broadly rounded. Two major head pores ( Fig. 3D ) with narrow connection between them. PP ca 1.1–1.3 IP. Lateral head pores of ca 0.9–1.0 IP length, lateral pore pockets semicircular, with depth about 1 pore length. Labral keel without denticles.

Postabdomen truncated, length about 2.5 heights. Distal margin straight, distal angle prominent, acute with rounded tip. Dorsal margin weakly convex in preanal part, concave in anal part, straight in postanal part. Distal part of dorsal margin 3 times longer than preanal one, with anal and postanal portion of similar length. Preanal and postanal angles weakly defined. Postanal margin of postabdomen provided with 10–14 marginal denticles. Anal margin with 4–5 clusters of marginal setules. 10–12 lateral fascicles of setules, distal setules in fascicle being longest. Postabdominal claw of moderate length, 1.5 times longer than preanal portion of postabdomen. Basal spine about 0.15 of length of claw.

Antennule with longest aesthetasc about 2/3 of length of antennule. Scrapers of limb II of similar morphology. Exopodite III with seta 6 of ca 2/3 length of seta 3. Exopodite IV with seta 3 being longest, setae 1–2 slightly shorter, setae 4–6 ca 0.4 length of seta 3. Epipodite IV–V without process. Exopodite V bilobed. Epipodite V with processes as long as epipodite itself.

Male

Length of adult 0.38–0.4 mm. Body low oval, dorsal margin weakly convex. Maximum height at the middle of the body, height/length ratio 0.55–0.58. Ocellus larger that in female.

Postabdomen moderately long, narrowing distally in postanal part. Ventral margin almost straight. Genital process about 1/3 length of postabdominal claw. Distal margin short, distal angle obtuse. Dorsal margin concave in anal portion, straight in postanal portion. Preanal and postanal angles not defined. Clusters of short setules in place of marginal denticles, distalmost cluster consisting of 3–5 thick short setules. Postabdominal claw as long as preanal portion of postabdomen, weakly curved. Basal spine not found.

Antennule with male seta arising at 1/4 length from tip, about 1/3 length of antennule.

Thoracic limb I with IDL setae 2 and 3 much thinner and two times shorter than in female, of similar length. Male seta curved, slightly shorter than seta 2. Ventral face of the limb under the copulatory brush with row of 20 long stiff setules. Inner seta (1) of endite 3 longer and thinner than in female, with long setules distally.

Differential diagnosis

Flavalona setigera comb. nov. differs from all species of Flavalona gen. nov. by the presence of only two major head pores.

Type material

Non-existent.

Material studied earlier

See Sinev (1999) for a list of material from Australia.

Type locality

New Zealand.

Distribution

Australia, New Zealand ( Sinev 1999a) and Brazil (Santos-Wisniewsky et al. 2001). Currently the only species with a transpacific range. However, since the limbs of American populations were not studied, these may turn out to represent a separate species.

Figures

Fig.3. A. Flavalona cheni (Sinev, 1999) comb. nov., head pores of parthenogenetic ♀. B–C. Flavalona natalensis (Sinev, 2008) comb. nov., parthenogenetic ♀. B. Lateral view. C. Head pores. D. Flavalona setigera (Brehm, 1931) comb. nov., head pores of parthenogenetic ♀. E–F. Flavalona weltneri (Keilhack, 1905) comb. nov., parthenogenetic ♀. E. Head pores. F. Postabdomen. Figures A and D from Sinev (1999a), B–C from Sinev (2008), E redrawn from Flössner (2000) and F redrawn from Van Damme et al. (2010).