Alona poppei Richard, 1897

Damme, Kay Van & Dumont, Henri J., 2008, Further division of Alona Baird, 1843: separation and position of Coronatella Dybowski & Grochowski and Ovalona gen. n. (Crustacea: Cladocera), Zootaxa 1960 (1), pp. 1-44 : 33-35

Note on Alona poppei Richard , A. novae-zealandiae Sars and A. eucostata Sars

A number of Alona rectangula- species outside the Palaearctic still need allocation to Coronatella . Candidates are the North American Alona circumfimbriata Megard 1967 (valid species; Frey 1988) and the Chinese A. rectangula tachystriata ( Chen et al. 1993) . These require a redescription, work in progress (Sinev, op. cit). Subspecies of Smirnov (1971) (e.g., A. richardi ) may be synonyms of A. rectangula ( Sinev 2001b; Frenzel 1987), but sympatric speciation in Europe within this complex should not be excluded. A further assignment of all obscure Alona species that may belong to Coronatella is beyond the scope of the present paper. We like to comment on a few taxa of the C. rectangula -complex, confused with C. anemae n.sp. but from different origins.

In Africa, several species descriptions correspond with C. anemae n. sp. Body size, habitus, shape of postabdomen, length of basal spine and the cluster of basal spinules provide useful characters for identifying C. anemae n.sp. in literature ( Table 1). Specimens depicted by Jenkin (1934) from Lake Naivasha, by Rey & St- Jean (1969) from Lake Chad as A. novae-zealandia e and by Delachaux (1917) as A. poppei , can be positively identified as C. anemae n.sp. So why not use these names? The confusion is the result of focusing on similarities between these taxa. Detailed descriptions of A. poppei and A. novae-zealandiae , suggest differences with C. anemae .

The South American A. poppei , found in Chili and Venezuela, has a conspicuous postabdomen with short anal margin and a terminal claw twice as long (see Richard 1897; Rey & Vasquez 1986) while in C. anemae these are of similar length; in addition, in A. poppei IDL setae have relatively stronger denticles and the first antennal endopod spine exceeds the length of the second segment (Rey & St-Jean 1986). A. poppei can be distinguished easily from C. anemae n.sp. We think A. poppei is restricted in distribution to the Neotropics.

The Australian/ New Zealand A. novae-zealandiae (figures in Sars 1904 and Smirnov 1971) seems closer in morphology to C. anemae and the former name was used to indicate latter species. Jenkin (1934) transferred the name to Africa. We studied a slide from Sars’ collection labelled “ Alona rectangula ?” from New Zealand to compare Sars’ rectangula- like species from this region. We depict few characters here of the adult male and female ( Fig. 14 ).

Sars depicted males only of A. eucostata , which he cultured for four years ( Sars 1894), not of A. novaezealandiae , of which he had only few specimens ( Sars 1904). The New Zealand slide we studied contained males and therefore specimens most likely correspond to Alona eucostata . Two possibilities: 1. there are two valid taxa of the C. rectangula complex in New Zealand ( eucostata and novae-zealandiae ), which, considering the complexity of this group, is possible; 2. there is only one species and novae-zealandiae is a junior synonym of eucostata (priority). In any case both names belong now to Coronatella instead of Alona due to closest affinities with C. rectangula .

Sars’ New Zealand specimens ( Fig. 14 ) differ from C. anemae n.sp. ( Figs 5–10 ) in a less pronounced preanal corner on the postabdomen, longer distal spines in each lateral fascicle, stronger IDL armature (P1) and a short postabdomen in males. The latter leaves no doubt that these New Zealand specimens are different from C. anemae and much closer to C. rectangula . Australian specimens of A. novae-zealandiae studied by Smirnov (1971) are similar to Sars’ specimens.

To conclude, Australian A. eucostata Sars, 1894 , A. novae-zealandiae Sars, 1904 (which may be a junior synonym) and Neotropical A. poppei Richard, 1897 need their detailed limb morphology documented in comparison to the taxa described in this paper. Together they comprise at least two full species, which belong to Coronatella and are different from C. anemae in morphology and origin.

Again, this illustrates the complexity and confusing state of the C. rectangula- complex, maybe more pronounced than in many Aloninae . With separation of this cryptic genus of Alona , work in Coronatella has just started. The situation for African taxa is also highly complex, discussed in the next section.

Figures

FIGURE 5. Coronatella anemae n.sp. A. Habitus, lateral view (Red Sea Hills, Sudan); B. Habitus, lateral view (culture from Rewgid, Socotra Island); C. Body outline; D. Head shield (Red Sea Hills, Sudan); E. First antenna; F. Second antenna (Sudan); G. Labral keel (Noged, Socotra); H. Labral keel (Rewgid, Socotra); I. Labral keel (Sudan); J. Posteroventral valve corner (Sudan); K. Postabdomen (Sudan); L. Postabdomen (Sharjah, UAE).

FIGURE 6. Coronatella anemae n.sp. SEM of habitus, culture from Rewgid, Socotra Island (Yemen). A. Lateral view; B. Dorsal view; C. Anterior view; D. Ventral view. Scale bar indicates 100µm.

FIGURE 7. Coronatella anemae n.sp., SEM parthenogenetic females from Socotra Island (Yemen). A. Head pores (from Qaysoh, Socotra); B. Second antenna (from Qaysoh); C. Postabdomen (Qaysoh); D. Postabdomen (Rewgid); E. Postabdomen (Noged), arrows indicate two conspicuous characters for C. anemae: long basal spine and well pronounced triangular preanal corner; F. First and second limb (Rewgid), ventral view.

FIGURE 8. Coronatella anemae n.sp. Adult parthenogenetic female, character variability between populations from different regions. A. Postabdomen (Uzbekistan); B. Idem, Aldabra (Seychelles); C. Idem, Socotra Island (Yemen), culture from Rewgid; D.–E. Idem, Qaysoh (Socotra); F. Idem, Noged (Socotra); G. Variation in terminal claw and basal spine morphology, three populations from Socotra Island; H. Head pore morphology from three populations, Socotra Island; I–M. Outer and inner distal lobes of P1 (note differences in IDL setulation and setae length) from Uzbekistan (I), Aldabra, Seychelles (J), Sudan (K), UAE (L), three populations from Socotra Island (M).

FIGURE 9. Coronatella anemae n.sp. Limb characters of parthenogenetic females (Rewgid, Socotra Island). A. First maxilla; B. First limb; C. Idem, anterior elements; D. Idem, ODL; E. Second limb; F. Idem, first three setae in filter comb; G. Third limb, exopodite; H. Idem, exopodite setae 5–6; I. Idem, endite; J. Idem, internal endite setae; K. Idem, gnathobase; L. Fourth limb, exopodite; M. Idem, setae 4–6; N. Idem, endite; O. Fifth limb; P. Idem, outline; Q. Idem, inner portion; R. Idem, element behind second endite seta (2’). For abbreviations, see Fig. 2.

FIGURE 10. Coronatella anemae n.sp. Adult male (Sudan, Red Sea Hills). A. Habitus; B. First limb, copulatory hook; C. Postabdomen; D. Postabdomen of C. rectangula = Alona rectangula (drawing after Alonso 1996).

FIGURE 14. Coronatella eucostata (Sars, 1894) = Alona eucostata Sars, 1894 (= Alona novae-zealandiae Sars, 1904?). Text on slide written by Sars reads “Alona rectangula? GOS New Zealand”. Zoological Museum Oslo F. 9737 Mp 269 ex coll G.O. Sars. Adult parthenogenetic female (A–D) and male (E–F). A–B. Postabdomen; C. First limb, ODL; D. Labral keel; E. Postabdomen (male); F. First limb (male), copulatory hook. Sars described two(!) species from the rectangula-complex, both from South Island of New Zealand: A. eucostata Sars, 1894 from Dunedin and A. novae-zealandiae Sars, 1904 from d’Urville Island (Sars 1894, 1904). They are very similar from descriptions and figures, but different in size (females resp. 0.48mm and 0.36mm; compare with sizes C. anemae and C. rectangula in Table 1).