Anthalona harti harti

Sinev, Artem Y. & Kotov, Alexey A., 2012, New and rare Aloninae (Cladocera: Anomopoda: Chydoridae) from Indochina, Zootaxa 3334, pp. 1-28 : 3-6

Anthalona harti harti Van Damme, Sinev et Dumont, 2011

Figures 1–2

Idris, 1983: 119–121, Fig. 57 ( Alona verrucosa ); Alonso, 1996: 317–318, Fig. 141 ( Alona verrucosa ); Sinev, 2002: 937, Fig 2 , д,и,м,п,у ( Alona verrucosa ); Maiphae et al., 2008: Fig. 2 A ( Alona verrucosa ); Van Damme et al., 2011: 18–22, Figs. 8–9 .

Material. 3 parthenogenetic females from Lake Kud-Thing in foodplain of the Mekong River, Nong Khai Province, Thailand, 28.11.1998, coll. C. Saeng-aroon, AAK 2003-033; 2 parthenogenetic females, Lake Bueng Khong Long in Nam Tok Tat Kham Forest Park, Nong Khai Province, Thailand, 31.08.2002, coll. J. Teeramaethee, AAK 2003-040; 6 parthenogenetic females, several exuvia from, paddy field II near Phitsanulok in foodplain of the River Nan, Phitsanulok Province, Thailand, 27.09.1996, coll. L. Sanoamuang, AAK 2004-050; 8 parthenogenetic females from littoral of Lake Tonle Sap, Cambodia, N 13º 14’ 17.4’’, E 103º 49’ 43.9’’, 30.01.2010, coll. A.Y. Sinev; 12 parthenogenetic females from a slow-through village pond in Ta Lai village near Cat Tien National park, Dong Nai Province, Vietnam, N 11° 22.354, E 107°20.773, 13.05.2009, coll. A.Y. Sinev.

Description of Indochinese populations. Parthenogenetic female. In lateral view, body oval, moderately high ( Fig. 1 A–B), maximum height at the middle of the body. Height-length ratio about 0.64–0.68. Dorsal margin convex, postero-dorsal and postero-ventral angles broadly rounded. Posterior margin almost straight. Postero-ventral angle ( Fig. 1 C) with about 40 setules not organized into groups. Ventral margin weakly convex, with about 35–40 setae. Anterior 7–10 setae long, next 10–12 setae very short, setae in the middle of anterior margin almost as long as anterior setae, toward posterior margin, length of setae gradually decreases. Antero-ventral angle rounded. Carapace sculpture as weakly defined longitudinal lines or tubercules.

Head relatively small, triangle-round in lateral view. In lateral view rostrum protruding downwards. Ocellus of variable size, in some specimens almost as large as eye. Distance from tip of rostrum to ocellus about 1–1.5 times of that between ocellus and eye.

Head shield ( Fig. 1 D) of typical for genus shape, in some specimens covered by tubercules. Rostrum short and rounded. Posterior margin notched. Two main head pores with a narrow connection between them ( Fig. 1 E), PP less than 0.3 IP. Lateral head pores located with bilobed, asymmetric cosmaria, at 0.5–0.7 IP distance from midline, at level before anterior main head pore.

Labrum of moderate size, without lateral projections ( Fig. 1 F). Labral keel wide, height about 1.5 times width. Anterior margin of keel convex, with small denticle in the upper third, apex rounded, posterior margin convex or wavy, without setules.

Thorax two times longer than abdomen. Dorsal surface of abdominal segments not saddle-shaped.

Postabdomen ( Fig. 1 G) short and wide, maximum height at preanal angle. Length about 2.3–2.4 height. Ventral margin weakly convex. Basis of claws separated from distal margin by clear incision. Distal margin straight, distal angle broadly rounded. Dorsal margin weakly convex in postanal portion and concave in anal one, distal part less than 1.5 times longer than preanal one, postanal portion 1.5 times shorter than anal one. Preanal angle prominent, postanal angle weakly defined. Preanal margin almost straight. Postanal margin with 4–5 well-developed, single sharp denticles, each with several spinules along anterior margin, size of denticles increasing distally. Length of longest denticles slightly more than width of base of postabdominal claw, 2.5–3 times exceeding width of denticle base. Anal margin with 4–5 groups of marginal spinules and setules. About 10 moderately wide lateral fascicles, posteriormost setae of each fascicle longest, about 2 times longer than neighboring marginal denticles. Postabdominal claw slender, of moderate length, shorter than preanal portion of postabdomen. Basal spine short and slender, about 0.2 of the claw length.

Antennule ( Fig. 1 H) of moderate size, length about 2.5 width, with 3 clusters of short setules at anterior face. Antennular seta of about half length of antennule, arising at 2/3 distance from the base. Nine terminal aestetascs of similar size, about 2/3 length of antennule.

Antenna short and massive ( Fig. 1 I). Basal segment robust, with short seta between branches, branches relatively short, all segments cylindrical, subequal in length. Basal and middle segment of endopodite with clusters of moderately short hard setules. Seta arising from basal segment of endopodite (omitted on drawing) thin, almost reaching end of endopodite. Seta arising from middle segment of endopodite of similar size to apical setae. Spine on basal segment of exopodite slightly longer than middle segment. Spines on apical segments slightly longer than apical segments.

Thoracic limbs: five pairs.

Limb I ( Fig. 2 A, B). Epipodite oval, with finger-like projection two times longer than epipodite itself. Accessory seta 2.5 times shorter than ODL seta. ODL seta with short setules in distal portion. IDL with two setae: seta 3 with massive, claw-like, longer than ODL seta, distal part of seta thin, with several setules; seta 2 similar to seta 3, but smaller, with additional straight spine at the middle. Endite 3 with four short setae. Endite 2 with three setae, two of them longer than ODL seta. Endite 1 with three setae, seta pointed to the limb base 1.5 times shorter than two others. Ventral face of limb with 5–6 clusters of long setules and 3–4 clusters of short setules below them.

Limb II subtriangular ( Fig. 2 C). Exopodite elongated, with short seta. Eight short scraping spines, spines 3 and 6 more massive than others, armed with 7–9 and 6–7 massive denticles, respectively. Distal armature of gnathobase with four elements. Filter plate II with seven setae, the posteriormost members much shorter than others.

Limb III. ( Fig. 2 D, E) Epipodite very long and narrow. Exopodite quadrangular, with six setae. Seta 3 longest, setae 4 and 5 about 1/3 and 1/2 length of seta 3, other setae short. Setae 1–4 plumose, seta 5 armed bilaterally with hard setules, seta 6 naked. Distal endite with 3 setae, two distalmost members scraping, slender, sharp, with denticles in distal part, short bottle-shaped sensillum located between their bases. Basal endite and gnathobase typical for the genus.

Limb IV ( Fig 2 F, G). Pre-epipodite setulated; epipodite with finger-like projection as long as epipodite itself. Exopodite subquadrangular, with six setae. Seta 1–3 long, of similar length, setae 4–6 about two times shorter, seta 5 longer than seta 6. Setae 1–4 flat, plumose, setae 5–6 thin, with short setules in distal portion. Inner portion of limb IV with four setae and small sensillum. Scraping seta slender, sharp, first flaming-torch much wider than two other. Three soft setae, basalmost seta significantly larger than others. Gnathobase with two-segmented seta and a small hillock distally. Filter plate IV with five setae.

Limb V ( Fig. 2 H). Preepipodite setulated, epipodite oval, with finger-like projection as long as epipodite itself. Exopodite oval, with four plumose setae. Seta 1–3 long, subequal in length, seta 4 short, three times shorter than seta 1. Inner lobe as oval lobe. At inner face, two setae, distal seta two times longer than basal. Filter plate V absent.

Ephippial female and male: for description, see Van Damme et al. (2011).

Size. Adult female 0.30–0.34 mm, male up to 0.23 mm.

Distribution. Recorded from South Europe ( Spain, Abkhazia), Africa, South-West Asia and Indochina.

Taxonomic notes. Populations of A. harti harti from Indochina do not differ significantly from those from South Europe, Africa, and South-West Asia ( Alonso 1996; Sinev 2002; Van Damme et al. 2011). Some minor structures of limbs, like sensillum of endite 1 of limb I and soft seta of limb II were not found in our material, but they are possibly overlooked beacause of their small size (we don’t have access to dark field vision optic, like Van Damme et al. (2011)). It is apparent that Alona harti is widely distributed, including in the Mediterranean region, Africa, and, possibly, in tropical and subtropical Asia – there are no data concerning the taxonomic status of the “ A. verrucosa ” records from India and China. A similar wide distribution was already recorded for Alona cambouei Guerne & Richard, 1898 ( Sinev 2001) . In Indochina, A. harti harti is the most common species of Anthalona.

Figures

FIGURE 1. Anthalona harti hart i Van Damme, Sinev & Dumont, 2011 from a slow-through village pond in Ta Lai village near Cat Tien National park, Dong Nai Province, Vietnam. A, juvenile female of instar II. B – I, adult parthenogenetic female: B, general view; C, posterior part of ventral margin of valves; D, head shield; E, head pores; F, labrum; G, postabdomen; H, antennule; I, antenna. Scale bars: A – B, D: 0.1 mm. C, E – I: 0.05 mm.

FIGURE 2. Anthalona harti harti Van Damme, Sinev & Dumont, 2011, from a flow-through village pond in Ta Lai village near Cat Tien National park, Dong Nai Province, Vietnam. Thoracic limbs of parthenogenetic female. A, limb I. B, ODL and IDL of limb I. C, limb II. D, exopodite of limb III. E, distal endite of limb III. F, exopodite of limb IV. G, inner portion of limb IV in inner and outer view. H, limb V. Scale bar 0.05 mm.

FIGURE 8. Celsinotum macronyx from a paddy field II, near Phitsanulok, foodplain of the River Nan, Phitsanulok Province, Thailand. A, juvenile female of instar II. Adult parthenogenetic female. B – C, lateral view. D, valve. E – F, antero-ventral and postero-ventral corners of valve. G, head in lateral view. H, head shield. I, head pores. J, adult male in lateral view. Scale bars, A – C, J and D, G – H: 0.1 mm; E – F, I: 0.05 mm.

FIGURE 9. Celsinotum macronyx, parthenogenetic female from a paddy field II, near Phitsanulok, foodplain of the River Nan, Phitsanulok Province, Thailand: A – D, specimen in lateral, anterior, antero-ventral and dorsal views. E, head pores. F, head, ventral view. G, postabdomen. H, postabdominal claw. I, distal portion of limb I. Scale bars, A – D, 0.1 mm; E – I, 0.01 mm.