Ovalona aguascalientensis ( Sinev & Silva-Briano, 2012 ) Sinev & Silva-Briano, 2012

Sinev, Artem Y., 2015, Revision of the pulchella - group of Alona s. lato leads to its translocation to Ovalona Van Damme et Dumont, 2008 (Branchiopoda: Anomopoda: Chydoridae), Zootaxa 4044 (4), pp. 451-492 : 472-474

XI. Ovalona aguascalientensis ( Sinev & Silva-Briano, 2012) comb. nov.

( Figs. 7 H–N)

Sinev & Silva-Briano, 2012: 2–8, Fig. 1–4 ( Alona ).

Type locality. Pond beside highway Villa Hidalgo city—Aguascalientes city, Aguascalientes state, Mexico. Type material. Holotype. Parthenogenetic female, MGU Ml 120. For list of paratypes see Sinev & Silva- Briano (2012).

Material studied earlier. For list of material from Mexico, see Sinev & Silva-Briano (2012). Diagnosis. Parthenogenetic female. General. Length of adult female 0.37–0.46 mm. Body regular oval, of moderate height, in adults height/length ratio about 0.59–0.63, maximum height at the middle of the body. Ventral margin with 35–45 setae. Postero-dorsal angle with about 80 setulae not organized into groups, and with 1–2 small triangular denticles in the majority of specimens.

Head. Posterior part of headshield with wavy margins and rounded tip. Three major head pores, connection between anterior and middle pore from well-developed, narrow to interrupted; connection between middle and posterior pore absent; PP about 0.4–0.6 IP.

Labrum. Labral keel wide, with rounded apex; anterior margin of keel convex or wavy; posterior margin without any setulae.

Second abdominal segment without dense setulae. Postabdomen of moderate width, with almost parallel margins in postanal portion, length about 2.5 heights. Distal margin straight to weakly convex, distal angle not prominent, broadly rounded. Dorsal margin with almost straight postanal portion and weakly concave anal portion. Distal part 1.7–1.8 times longer than preanal one, with postanal portion slightly longer than anal. Preanal angle well-defined, postanal angle not defined. 8–9 well-developed marginal denticles of similar size, and with three-four groups of marginal setulae on anal margin. Eight-ten wide lateral fascicles of setulae, six-seven distalmost fascicles large, with distalmost seta of each fascicle 1.5 times longer than marginal denticles. Postabdominal claw of moderate length, slightly longer than preanal portion of postabdomen. Basal spine about 0.3 of length of claw.

Antennule with antennular seta about 1/3 length of antennule, arising at 2/3 distance from the base. Aesthetascs of different length, two longest of them of about 2/3 length of antennule.

Antenna with seta arising from basal segment of endopodite of same length as endopodite. Spine on basal segment of exopodite shorter than middle segment. Spines on apical segments slightly longer than apical segments.

Limb I with accessory seta about 1/3 length of ODL seta. Limb III with exopodite seta 3 being longest; seta 6 about 1/3 of seta 3; setae 1 and 4 about 1/4 length of seta 3; other setae shorter. Limb IV with epipodite with very short projection. Exopodite IV seta 3 longest; setae 1 and 2 about 2/3 length of seta 3; seta 5 about 1/2 length of seta 3; setae 4 and 6 two times shorter than seta 5. Flaming-torch setae of limb IV with reduced distal portion. Limb V with epipodite with short projection. Exopodite seta 4 four times shorter than seta.

Ephippial female unknown.

Male. General. Length 0.36–0.37 mm. Body low oval, maximum height in the middle of the body, body height/body length about 0.58. Ocellus smaller than eye.

Postabdomen short, strongly narrowing distally in anal portion, subrectangular in postanal portion. Distal angle weakly broadly rounded, not protruding. Preanal angle well-defined, postanal angle not defined. Distal part of postabdomen 1.2–1.3 times longer than preanal; anal and postanal margins of similar length. Dense clusters of short setulae in place of marginal denticles, lateral fascicles of setulae same as in female. Postabdominal claw very short, 2.5 times shorter than preanal portion of postabdomen; basal spine very long, almost straight, about 2/3 of claw length.

Antennule with male seta arising at 1/4 length from tip, about 1/5 of antennule length. Limb I with IDL seta 1 very small, setae 2 and 3 thinner and 1.5 times shorter than in female, male seta large, hook-like, almost as long as seta 3. A group of about ten thick setulae, followed by group of five thinner setulae, located under copulatory brush on ventral face of limb.

Full description. See Sinev & Silva-Briano (2012).

Differential diagnosis. O. aguascalientensis differs from other species of cambouei -group by the morphology of its head pores, all species of the group having either fully connected or fully disconnected pores. An unique feature of O. aguascalientensis is the presence of denticles on posteroventral corner of valves, which are never present in any other species of the group, although some specimens can lack them. O. aguascalientensis differs from O. karelica and O. bromelicola by the long basal spine of the postabdominal claw. O. aguascalientensis differs from O. glabra , O. archeri , O. cambouei and O. pulchella by weakly protruding distal angle of postabdomen and postanal marginal denticles of postabdomen being of the same size.

Distribution. Known only from Aguascalientes State of Mexico, Central Mexican Plateau.

Figures

FIGURE 1. Ovalona nuragica from small temporary pond near Laguna de Bonache, near Siles town, Jaén, Spain. A, juvenile female of instar I; B, juvenile female of instar II; C – I, adult parthenogenetic female; C – D, lateral view; E, ventral margin of valves; F, setae from posterior part of ventral margin of valves; G, posteroventral angle of valves; H, head shield; I, head pores; J, ephippial female; K, adult male.

FIGURE 2. Ovalona nuragica from small temporary pond near Laguna de Bonache, near Siles town, Jaén, Spain. A – E, parthenogenetic female; A – B, same specimen in lateral and latero-frontal view; C, head pores; D, main head pores; E, lateral head pore; F, ephippial female.

FIGURE 3. Ovalona nuragica from small temporary pond near Laguna de Bonache, near Siles town, Jaén, Spain. A – J, parthenogenetic female. A, variability of labral keels; B, postabdomen; C, postanal margin of postabdomen; D, postabdominal claw; E, antennule; F – G, antenna; H – I, thoracic limb II; J, thoracic limb V; K – M, adult male. K, postabdomen; L, distal part of postabdomen; M, antennule.

FIGURE 4. Ovalona nuragica from small temporary pond near Laguna de Bonache, near Siles town, Jaén, Spain. A – E, thoracic limbs parthenogenetic female. A, limb I; B, exopodite of limb III; C, inner portion of limb III; D, exopodite of limb IV; E, inner portion of limb IV; F, adult male, limb I; G – K, parthenogenetic female with abnormal morphology of limbs; G, ejector hooks of limb I; H, endite 1 of limb I; I – J, inner portions of limbs III; K, inner portion of limb IV.

FIGURE 7. A – B, Ovalona weinecki (Studer, 1878), parthenogenetic female. A, lateral view, redrawn from Frey, 1988; B, postabdomen, redrawn from Van Damme & Dumont, 2008; C – G, Ovalona archeri (Sars, 1988), from Sinev (2002 c). C – E, parthenogenetic female. C, lateral view; D, head pores; E, postabdomen; F – G, adult male. F, lateral view; G, postabdomen; H – N, Ovalona aguascalientensis (Sinev & Silva-Briano, 2012), from Sinev & Silva-Briano (2012). H – L, parthenogenetic female. H, lateral view; I, posteroventral margin of valves; J – K, head pores; L, postabdomen; M – N, adult male. M, lateral view; N, postabdomen.