Agabus raffrayi Sharp, 1882

Englund, William F., Njoroge, Laban, Bistroem, Olof, Miller, Kelly B., Bilton, David T. & Bergsten, Johannes, 2020, Taxonomic revision of the Afrotropical Agabus raffrayi species group with the description of four new species (Coleoptera, Dytiscidae), ZooKeys 963, pp. 45-79 : 45

publication ID	https://dx.doi.org/10.3897/zookeys.963.53470
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scientific name	Agabus raffrayi Sharp, 1882
status

Treatment

Agabus raffrayi Sharp, 1882 Figures 1 View Figure 1 , 2B View Figure 2 , 3B View Figure 3 , 5A-C View Figure 5 , 8D View Figure 8 , 10D View Figure 10 , 11D View Figure 11 , 11I View Figure 11 , 12 View Figure 12 , 13 View Figure 13 , 14 View Figure 14

Agabus raffrayi Sharp, 1882: 501-502

Agabus limbicollis Régimbart, 1905: 224-225 (Syn. Nilsson 1992a)

Type locality.

raffrayi “Abyssinia” [Ethiopia]; limbicollis "Abyssinie: Auato, au bord du Nil Bleu, dans le Gindeberat" [Ethiopia: Auato, on the banks of the Blue Nile, in the Gindeberat].

Type material.

Lectotype ♂ of raffrayi (BMNH) labelled: "♂ Abyssinia, Raffray 782", “Type”, "Sharp Coll 1905-313.", "Type 782 Agabus Raffrayi n.sp. Abyssinia", "LECTOTYPUS ♂ Agabus raffrayi Sharp, 1882 Des. A.Nilsson, 1989". Lectotype ♂ of limbicollis (MNB) labelled: "N.O. - Africa, Schoa, Falle O. Neumann S.", "610 Falle", " Agabus limbicollis Rég. Type.", "LECTOTYPUS ♂ Agabus limbicollis Régimbart, 1905. Des. Nilsson -90".

Diagnosis.

With a prolonged preapical section of male aedeagus and a pronotal hypomeron which is not visible in lateral view, this species is most similar to A. pallidus and A. ruwenzoricus . From the former it is separated by its broader metasternal wing (Figs 2 View Figure 2 , 12 View Figure 12 ) and from the latter by the lack of interocular spots (compare Fig. 4D, B View Figure 4 ).

Description.

Habitus as in Fig. 11D, I View Figure 11 .

Colour: Head black, most specimens with a small rufous anterior area, interocular spots not present. Pronotum black with rufous margins. Elytra rufotestaceous to brown. Ventral surface black, hypomeron and epipleuron testaceous. Legs rufous to rufopiceous. Antennae and palpi testaceous to rufotestaceous.

Microreticulation : Medium impressed on head, pronotum and elytra, similar in both sexes. Composed of a mixture of small and somewhat larger, uneven meshes.

Structural features : Body length: 6.96-8.24 mm (see Table 1 View Table 1 ). Hypomeron not visible in strict lateral view (Fig. 10D View Figure 10 ), lateral bead of pronotum well defined (see Fig. 10D View Figure 10 ). Metasternal wing broad, WC/WS less than 2.9 (see Table 1 View Table 1 , Figs 2B View Figure 2 , 12 View Figure 12 ). Pronotum broad, more than twice as broad as interocular distance (see Table 1 View Table 1 , as in Fig. 4B View Figure 4 ).

Legs: Protarsal claws long,> 1.6 × as long as protarsomere 4 in all males and most females (see Table 2 View Table 2 , Fig. 14 View Figure 14 ). Metatarsomeres short and broad; metatarsomere 2 <1.6 × as long as broad (see Table 2 View Table 2 ), metatarsomere 5 <3.0 times as long as broad (see Table 2 View Table 2 ).

Male genitalia: Subapically broadened, and prolonged between the subapical broadening and the apical and subapical teeth. Subapical tooth with quite variable shape (see Figs 8D View Figure 8 , 5A-C View Figure 5 ).

Female: Externally similar to males but colour of the elytra tends to be slightly lighter.

Distribution.

Ethiopia (see Fig. 1 View Figure 1 ). Rocchi (1975) listed the distribution of A. raffrayi to also include the Democratic Republic of the Congo, Uganda, Rwanda, Tanzania, Zimbabwe, and South Africa but these specimens are likely to belong to other species.

Habitat.

Found in small, often temporary, streams and pools in streambeds at elevations between 2100 to 3200 m ( Nilsson and Persson 1990, 1993; Nilsson 1992a).

Etymology.

The name refers to the collector of the type specimens, Achille Raffray. The name of the synonym A. limbicollis refers to the well-defined lateral bead of the pronotum (Latin: limbus = border, collum = neck).

Comments.

The fact that A. raffrayi and A. pallidus are distinguishable only on the width of the metasternal wing led some previous authors to suggest the occurrence of a single species which was dimorphic with regard to this character ( Jackson 1956). Nilsson and Persson (1990) provided a detailed account of this argument, analysed a large series of specimens and concluded that the variation should rather be interpreted as two separate species. We agree with this assessment and concur that male genitalia are not diagnostic for these two species, only the width of the metasternal wing being reliable. In our measurements, the pronotum is marginally broader in A. pallidus but the small sample size forbids any strong conclusions at present (Fig. 13 View Figure 13 ).

Nilsson (1992b) described the larval morphology of Agabus raffrayi along with some representatives of two other Afrotropical Agabus groups.