Cont. Ref. arb.sig. Gen.


Baetis * Nigrobaetis * Labiobaetis * Acentrella * Baetiella



Cont. Ref. Classif. Gen.


Acentrella/fg1 * pm.Acentrella/fg2

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. 1994Поденки 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.




Groups of subgenera



Manner of folding of subimaginal gonostyli under cuticle of mature larva




scales on integument

setae on inner margin of mandibles

lateral parapsidal sutures of mesonotum

Group of subgenera Nigrobaetis (includes subgenera Nigrobaetis, Fallceon, Caribaetis, Americabaetis)

All segments directed caudally (Fig.1:2,5,7,10,12,15,18,10,21)


In angulated nests with operculae on corners (Fig.4:25-27; 5:19,28-33)

Present (Fig.4:19; 6:2,3) or absent (Fig. 5:1,2)

Without sharp curvation, smoothly fall into median parapsidal sutures (Fig.1:1,2)

Group of subgenera Labiobaetis (includes subgenera Labiobaetis, Acerpenna)

2nd and 3rd segments directed medially, but most caudal is middle of 2nd segment (Fig.2:23-25)

Indistinct or absent

Group of subgenera Baetis (includes subgenera Baetis s.str., Acentrella, Baetiella)

2nd segment directed medially, most caudal is 3rd segment (Fig.2:26,27)


In semicircular nests without operculae or absent


Without sharp curvation at connections with median parapsidal sutures (Fig.1:3)

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






2nd segment of labial palp


unpaired setae on claw

hind wing


With keel

Without projection

Not wide


As in Baetis s.str.


With keel

Without projection

Not wide


As in Cloeoninae



Without projection

Not wide


As in Cloeoninae



With projection




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


B. supergroup


II group:


I group:


III group:


IV group:


V group:


Prostheca of right mandible

(as in most Baetidae)

In form of 2 setae 
(Fig.4:19; 5:2; 6:3
(the same in Cloeodes)


Asymmetric, with papillae 

Symmetric, oval, with multi-layer cover, without papillae 
and usually without regular sculpture (as in Baetis s.str.)



Medium width (Fig.4:32; 5:4; 6:8

Paraproct of larva

Without projection 
(as in most Baetidae)

With projection 
(Fig.4:24; 5:11; 6:6)

Head of female imago

Not wide, eyes relatively large 

Wide, eyes small 

Frontal suture of larva

Long, each half S-bent 
(Fig.4:20; 5:13)

Short, blunt-angled,

slightly bent (Fig.6:4)

Turban eye of male imago

Wider than lower eyes

Narrower than lower eyes

Length of facetted surface 
of turban eye of male imago
(Table 3)






Last segment of gonostylus
of male imagi

Long, spindel-shaped


Short or long



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.