Campsicnemus lobatus

Evenhuis, Neal L., 2008, The Campsicnemus lobatus and zigzag groups in the Society Islands, French Polynesia (Diptera: Dolichopodidae), Zootaxa 1910, pp. 27-44 : 28-29

The lobatus group

Diagnosis. Species in the Campsicnemus lobatus group are easily distinguished by the spot of color at the apex of the radial portion of the wing ( Figs. 5, 6, 8, 9 ) and/or the small spot at the apex of vein CuA1 ( Figs. 7– 9 ). Species are usually dark in coloration with an almost all black head and thorax while the abdominal tergites may be all dark brown to black or with some yellow patterning on the basal segments. The species in the lobatus group comprise some of the largest species in the genus (4–7 mm in length). This species group is restricted to the Society Islands in French Polynesia and all members are associated with wet, shady seeps. Water-skating Campsicnemus are present in the Marquesas and the Hawaiian Islands where gerrids are absent. Gerrids are present in the Society Islands and it is theorized here that the species in the lobatus group have evolved from the water surface-inhabiting species to shady seep-inhabiting species on the rock walls adjacent to these pools in order to avoid competition and/or predation from the gerrids in the pools below them.

Included species:

borabora Evenhuis , n. sp. (Society Islands [Bora Bora]).

lobatus Evenhuis , n. sp. (Society Islands [Moorea]).

paralobatus Evenhuis , n. sp. (Society Islands [Tahiti]).

rheocrenus Evenhuis , n. sp. (Society Islands [Tahiti]).

tunoa Evenhuis , n. sp. (Society Islands [Moorea]).

Remarks. A single female from Taha’a has been examined during this study and may represent an additional new species but until males from Taha’a are collected, its species identification cannot be ascertained.

Figures

FIGURES 5 – 9. Campsicnemus lobatus group wings. 5. C. lobatus; 6. C. rheocrenus; 7. C. borabora; 8. C. paralobatus; 9. C. tunoa.