Diagnoses for Nigrobaetis and subordinated taxa

After the first diagnosis of Nigrobaetis  by Novikova & Kluge 1987  , a paper with corrections an additions appeared:

[Novikova E.A. & Kluge N.J.] Новикова Е.А., Клюге Н.Ю. 1994. Поденки подрода Nigrobaetis (Ephemeroptera, Baetidae, Baetis). [Mayflies of the subgenus Nigrobaetis (Ephemeroptera, Baetidae, Baetis)]. // Энтомологическое Обозрение 73(3): 623–644 [Entomologicheskoe Obozrenie = Revue d'Entomologie de l'URSS] 73(3): 623–644.

Table 1 on p.624 in Novikova & Kluge 1994:

Characters of groups of subgenera in the genus Baetis s.l.

Text on p. 623 in Novikova & Kluge 1994:

The group of subgenera Nigrobaetis includes subgenus Nigrobaetis, distributed mainly on the Old World, and American, mainly Neotropical, subgenera Fallceon, Americabaetis and Caribaetis, and, possibly, some other non-Palaearctic taxa. Characters of the subgenera of the Nigrobaetis group are given in the Table 2.

We did not find differences of Nigrobaetis and Fallceon in morphological characters of larvae. These subgenera are distinguished by shape of imaginal hind wing (if hind wings are not reduced): in Nigrobaetis hind wings are relatively wide, with small non-curved costal projection (as in Baetis s.str.), often with furcation of the second vein (Fig.3:13-20); in Fallceon hind wings are narrow, with long hooked costal projection (as in Caribaetis and in the subfamily Cloeoninae). Larvae of the subgenera Nigrobaetis and Fallceon differ by manner of their respiratory movements: larvae of Fallceon either do not make respiratory movements, or make primitive dorsoventral movements (Kluge 1992:13-20); larvae of Nigrobaetis make lateral respiratory movements, like larvae of the subgenus Baetis s.str. (Kluge, Novikova & Brodsky 1984), but in contrast to Baetis s.str., larvae of Nigrobaetis do not bent abdomen, but shake from side to side by the whole body.

Table 2 on p.625 in Novikova & Kluge 1994: 

Characters of subgenera of the group Nigrobaetis

Text on p.625 in Novikova & Kluge 1994:

The subgenus Takobia was established by us for a single species Baetis maxillaris on that reason, that in larva of this species, unlike all other Baetis s.l., claws lack denticles, and mouthparts are similar to that og the genus Cloeon (Novikova & Kluge, 1987). However, later we reared male imagines of this species, and, besides this, found another species, B. kogistani sp.n., which inhabits together with B. maxillaris. Both species have so great similarity in genital structure (Fig.6:21; 7:1) and other details of imagines and larvae, that there close relationship is doubtless; at the same time, B. kogistani has structure of larval claws and mouthparts typical for Nigrobaetis. Because of this, now we regard B. maxillaris to be not a representative of a separate subgenus, but an aberrant form of the subgenus Nigrobaetis. In the original description of the subgenera Nigrobaetis and Takobia, we noted a difference in the pose of buds of subimaginal gonostyli under cuticle of mature larvae. The Fig.2 shows development of subimaginal gonostyli in course of metamorphosis in various species of the genus Baetis. From these figures one can see, that in different species of the subgenus Nigrobaetis the gonostyli buds are folded differently. In B. (N.) gracilis, B. (N.) bacillus, B. (N.) acinaciger, B. (N.) muticus, B. (N.) talasi and B. (N.) kogistani, there is well a well visible sharp lateral fold at the middle of the second segment, and this fold can be retained in subimago after emergence (Fig.2:7-19,21,22); in B. (N.) niger and B. (N.) digitatus the lateral fold of second segment is smaller and locates more proximally (Fig.2:1-6). Generally, manner of gonostyli folding in all Nigrobaetis (including B. maxillaris) belongs to the same type, peculiar to the group of subgenera Nigrobaetis, which differs from that of the groups of subgenera Labiobaetis and Baetis (Fig.2:23-27).

As a subgeneric  character of Takobia, we noted also that posterior margin of head of female imago has no incision, while in Nigrobaetis the median incision on posterior head margin is present. Examination of greater number of specimens of B. (N.) muticus, B. (N.) kars, B. (N.) kogistani and B. (N.) maxillaris reveals that these species have identical structure of female hind head margin: it is convex, medially with a very small incision or without it (Fig.5:23,24).

To the genus Diphetor, two North American species were attributed (McCafferty & Waltz, 1990), while larvae are described only for the type species – Baetis hageni Etn. Judging by its description, Diphetor has no difference from Nigrobaetis. The original description of the genus Diphetor was published in the same year, but somewhat later, than that redescription of the subgenus Nigrobaetis, which provides availability of this name, thus priority belongs to the name Nigrobaetis.

Table 4 on p.631 in Novikova & Kluge 1994:

Characters of supergroups and groups of species in the subgenus Nigrobaetis

A. Supergroup niger-gracilis (p.631)

    I. Group niger (p.631)

        1. Baetis (Nigrobaetis) niger (Linnaeus 1761) (type species of Nigrobaetis) (p.631)

        2. Baetis (Nigrobaetis) digitatus Bengtsson 1912 (p.632)

        -. Baetis (Nigrobaetis) harasab Soldan 1977

    II. Group gracilis (p.634)

        3. Baetis (Nigrobaetis) gracilis Bogoescu et Tabacaru 1957 (p.634)

        4. Baetis (Nigrobaetis) bacillus Kluge 1983 (p.635)

        -. Baetis (Nigrobaetis) numidicus Soldan et Tomas 1983

        -. Baetis (Nigrobaetis) gombaki Müller-Liebenau 1984

        -. Baetis (Nigrobaetis) mirabilis Müller-Liebenau 1984

B. Supergroup muticus-acinaciger-maxillaris (p.635)

    III. Group acinaciger (p.635)

        5. Baetis (Nigrobaetis) acinaciger Kluge 1983 (p.635)

        -. Baetis (Nigrobaetis) hageni Eaton 1884 (type species of Diphetor)

    IV. Group muticus (p.635)

        6. Baetis (Nigrobaetis) muticus (Linnaeus 1758) (p.635)

        7. Baetis (Nigrobaetis) kars Thomas et Kazanci 1989 (p.635)

        8. Baetis (Nigrobaetis) ralasi Novikova et Kluge 1994 (p.635)

        -. Baetis (Nigrobaetis) navasi Müller-Liebenau 1974

        -. Baetis (Nigrobaetis) albinatii Sartori et Thomas 1989

        -. Baetis (Nigrobaetis) oukaimeden Thomas et Sartori 1991

        -. Baetis (Nigrobaetis) laetificus Müller-Liebenau 1984

    V. Group maxillaris (p.637)

        9. Baetis (Nigrobaetis) kogistani Novikova et Kluge 1994 (p.637)

        10. Baetis (Nigrobaetis) maxillaris (Braasch et Soldan 1983) (p.641)

Species of uncertain systematic position:

        11. Baetis (Nigrobaetis?) sp.