Scaptomyza (Engiscaptomyza)

O’Grady, Patrick, Bonacum, James, Desalle, R. & Val, Francisca Do, 2003, The placement of Engiscaptomyza, Grimshawomyia, and Titanochaeta, three clades of endemic Hawaiian Drosophilidae (Diptera), Zootaxa 159 (1), pp. 1-16 : 9-10

Scaptomyza (Engiscaptomyza)

Diagnosis. Mesonotum typically with five dark brown to black vittae extending the full length, the lateral vittae may be interrupted at the suture ( Kaneshiro 1969). The male genitalia of the Engiscaptomyza species are also quite similar to those of the genus Scaptomyza , characterized by large lobes of the epandria and prominent surstyli ( Fig. 4 ). Some species (i.e., S. crassifemur ) also possess enlarged, swollen femora.

Included Taxa. Scaptomyza (Engiscaptomyza) ampliloba (Hardy) , comb. nov. from Kaua‘i, S. (Engiscaptomyza) crassifemur (Grimshaw) , comb. nov. from Maui and Moloka‘i, S. (Engiscaptomyza) inflata (Kaneshiro) , comb. nov. from O‘ahu, S. (Engiscaptomyza) lonchoptera (Hardy) , comb. nov. from Maui, S. (Engiscaptomyza) nasalis (Grimshaw) , comb. nov. from Maui and Moloka‘i, S. (Engiscaptomyza) reducta (Hardy) , comb. nov. from Hawai'i, S. (Engiscaptomyza) undulata Grimshaw comb. nov. from Hawai‘i ( Nishida 2002)

Discussion. Kaneshiro (1969) recognized a single species group ( crassifemur ) containing two subgroups ( crassifemur and nasalis ) within this subgenus. We will leave all taxonomic ranks below the level of subgenus intact. The polytene chromosome of the subgenus Engiscaptomyza , unlike those of the remainder of the genus Scaptomyza , are large and easy to decipher. Yoon et al. (1975) examined the phylogenetic relationships between four species of the subgenus Engiscaptomyza using polytene chromosome banding patterns. Their work suggests that S. reducta (Hawai‘i) and S. crassifemur (Maui Nui) are sister taxa. Scaptomyza inflata (O‘ahu) is basal to this group and S. ampliloba (Kaua‘i) is the most basal member of this subgenus.

KEY TO SPECIES OF THE SUBGENUS Engiscaptomyza Kaneshiro

10. Mesonotum vittate….................................................................................................. 11

­ Mesonotum lacking vittae .......................................................................................... 15

11. Distinct infuscations along margin of wing, veins and crossveins, median portions of most cells are hyaline; front tarsi of male with numerous erect dorsal setae. Hawai‘i ... ...................................................................................................... undulata (Grimshaw)

­ Wings faintly and evenly infuscated, no distinct markings ........................................ 12

12. Surstylus sharply concave, with distinct lobe at apex which forms a “C” shape; dorsal lobe of hypandrium narrowly pointed, with indistinct protrusion (see Kaneshiro, 1969; Fig. 1 ) .............................................................................................. ampliloba (Hardy)

­ Surstylus less concave, straighter in profile ............................................................... 13

13. Protrusion on dorsal lobe of hypandrium somewhat short, indistinct............................. .......................................................................................................... inflata (Kaneshiro)

­ Protrusion on dorsal lobe of hypandrium elongate, finger­like ................................. 14

14. Front femur swollen, rufous in color; scutellum with additional setulae inserted on margin between anterior and posterior scutellar setae; ovipositor blunt, with ca. 5 elongate setulae along margin. Maui, Moloka‘i ............................ crassifemur (Grimshaw)

­ Front femur swollen (not as distinctly as above), entirely black in color; scutellum only bears anterior and posterior scutellar setae; ovipositor blunt, with only a single elongate setula present at apex. Maui, Moloka‘i ........................... nasalis (Grimshaw)

15.Legs entirely yellow,except for brown apex of tarsus;leg segments short and thick. Hawai‘i reducta (Hardy)

­ Femora almost entirely brown, tinged faintly with black and narrowly yellow at the bases and apices; tibia yellow with a broad brown band at apex and basal 1/3 of segment; tarsi yellow, tinged faintly with brown on apical segments. Maui ....................... ....................................................................................................... lonchoptera (Hardy)

Figures

FIGURE 1. Phylogenetic relationships of the Hawaiian Drosophilidae (after Bonacum 2001), with particular emphasis on the genus Scaptomyza and associated groups (Titanochaeta, Grimshawomyia, and Engiscaptomyza). Numbers above the line at each node are bootstrap proportions, numbers below the line are decay indices (after Bonacum 2001; see text for details). Numbers of species sampled/total species described in a group is tabulated individually for the Hawaiian Drosophila lineages, as well as for the Hawaiian Drosophila and genus Scaptomyza as a whole (numbers are not additive due to species unplaced in described groups). Chromosome numbers for the ancestor of the Hawaiian Drosophilidae (N=6) and groups where two independent fusions are inferred (modified mouthpart group and genus Scaptomyza) are mapped on the tree, after (Clayton et al. 1972; Yoon et al. 1975).

FIGURE 4. Male terminalia of Scaptomyza (Engiscaptomyza) undulata (Grimshaw).