Monospilus Sars, 1862

Sinev, Artem Y., 2016, Key for identification of Cladocera of the subfamily Aloninae (Anomopoda: Chydoridae) from South-East Asia, Zootaxa 4200 (4), pp. 451-486 : 478

Monospilus Sars, 1862

Parthenogenetic female short description. Body round in lateral view ( Fig. 14A ), only weakly compressed laterally. The only genus of Aloninae in South-East Asia retaining valves from the previous molts and lacking eye. Posteroventral corner of valves without denticles. Rostrum short; rostrum tip truncated with four blunt denticles. Single small, rounded main head pore; lateral pores absent. Labral keel of moderate width, with wavy anterior margin and a rounded apex, with cluster of setulae on posterior margin.

Postabdomen short and wide, with anal margin 1.5 times longer than postanal, without defined distal angle and distal margin. Preanal angle and postanal angles well-defined. Postanal denticles short. Postanal lateral groups composed by short thick setulae. Postabdominal claw short, curved, with moderately long basal spine.

Antennule without lateral aesthetascs; all terminal aesthetascs of similar length. Antennal seta without basal peg. Antenna with thin seta on basal segment of endopod. Spine on basal segment of exopod much longer than middle segment. Spines on apical segments much longer than apical segments. IDL of limb I with three setae; seta 1 very short, setae 2–3 thin, armed with strong spinulae.

Single species, Monospilus dispar Sars, 1862 ( Fig. 4 A). Length of adult up to 0.5 mm. Rare in the region, found in streams on sandy bottom. Probably a species-complex; M. dispar is common in Holarctic, but was also reported from Africa, Australia and South America . In South-East Asia known from North Vietnam ( Thanh et al., 1980) and Hainan (Sinev et al., 2015). For detailed description see Alonso, 1996.

Figures

FIGURE 4. Characteristics used for the genera identification key of Aloninae. Theses 21 – 23.

FIGURE 14. A, Monospilus dispar Sars, 1862, lateral view. B – E. Nicsmirnovius eximius (Kiser, 1948). B, lateral view. C, head pores. D, postabdomen. E, IDL of limb I. F – I. Ovalona cambouei (Guerne & Richard, 1893). F, lateral view. G, head pores. H, postabdomen. I, IDL and ODL of limb I. J – L. Ovalona archeri (Sars, 1888). J, lateral view. K, head pores. L, postabdomen. (A – E, orig.; F – I, from Sinev (2015); J – L, from Sinev (2002 )).