A review of the genera comprising species of the genus Eurynogaster sensu Hardy & Kohn, 1964 in Hawai‘i (Diptera: Dolichopodidae)
Author
Evenhuis, Neal L.
text
Zootaxa
2005
2005-07-12
1017
39
60
journal article
11755334
EC70BA0E-3C6D-4CC2-A16E-EC0E543CA917
Genus
Major
Evenhuis
,
gen. n.
(
Figs. 8
,
12a
,
17
,
25
)
Type
species
:
Paraliancalus minor
Parent, 1938
, by present designation.
Diagnosis
: The genus is easily recognized among Hawaiian dolichopodids by its conspicuously large tarsal claws (present in both males and females) combined with the long, thin,
recurved and fused cerci of the hypopygium, and large unilobed surstyli without conspicuous setation (
Fig. 25
).
FIGURES 13–20
. Male wings.
13
.
Adachia williamsi
(Hardy & Kohn)
.
14
.
Arciellia flaviventer
(Hardy & Kohn)
.
15
.
Elmoia viridifacies
(Parent)
.
16
.
Eurynogaster clavaticauda
Van Duzee.
17
.
Major minor
(Parent)
.
18
.
Sigmatineurum binodatum
(Parent)
.
19
.
Sweziella virida
(Van Duzee)
.
20
.
Uropachys palustricola
(Hardy & Kohn)
.
Description
:
Male
. Body length: 3.5–4.5 mm. Wing length: 3.5–5.2 mm.
Head
. Generally shining metallic; face equal to distance between lateral edges of antennal sockets (cf.
Fig. 1
), parallel to clypeus; ventral margin of clypeus ending just above lower margin of eyes; palpi extending below eyes. Antennae with first flagellomere long, rounded apically, length ca. 3 x width; arista dorsal, bare, with micropubescence only at tip. Ocellars large, 1/4–1/3 head height; verticals absent.
Thorax
. Generally shining metallic dorsally, pleura subpollinose. Chaetotaxy as follows: 5
dc
; 2
np
; 1
ph
; 1
pa
; 1
sc
; 2
sa
;
ac
absent.
Legs
. Coxae I–III predominantly bare, short fine hairs apically. All femora with ventral bristles, strongest on FII and FIII. Tibia II and TIII with a few strong setae. Claws large (
Fig. 12a
).
Wing
(
Fig. 17
). With dense brown microtrichia giving wing a smoky brown appearance. CuAx ratio about 2.
Abdomen
. Shining metallic dorsally, pollinose on sternites. Segments I–V subequal in length; abdominal hairs generally short, longer on posterior margins of tergites, sternite IV bilobed to accommodate terminalia.
Hypopygium
(
Fig. 25
). Ovateelliptical; extending forward to posterior margin of 4th segment; cerci fused basally, sclerotized along entire length, recurved on apical 1/4, tip slightly swollen with dark sclerotization; surstylus unilobed, robust, without strong setation; basiventral epandrial lobe long, thin, with apical setae; hypandrium broad basally, then tapering to recurved pointed apex.
Female
. As in male except for genitalic features; legs normal, without modifications.
Discussion
: Only one species,
Major minor
(Parent)
, is known.
Parent (1938)
originally described the species in
Paraliancalus
with which it does have certain similarities; however, the cerci are differently modified and the claws are extremely large (relatively normal sized in
Paraliancalus
). He later (
Parent 1940
) transferred the species to
Eurynogaster
with the following caveat: “J’ai été amené à ranger dans le genre
Eurynogaster
, la forme que j’avais décrite sous le nom
Paraliancalus minor
, bien que cette dernière espèce soit un peu aberrante dans ce genre.” Parent was correct in his assumption of it being an aberrant species in that genus; yet subsequent workers kept the species in
Eurynogaster
, possibly without having properly studied the male genitalia. Examination in this study confirms that the species does not fit the generic limits of
Eurynogaster
or any other known genus and is here transferred to the new genus
Major
.
Williams (1940)
conducted biological observations on the species and found it commonly at seeps near Mt. Ka‘ala in the Wai‘anae range on O‘ahu. Its large claws are similar to the size found in species of the Marquesan sympycnine genus
Humongochela
Evenhuis (
Evenhuis 2004
)
, which are also found clinging to wet vertical seeps; and in
Sigmatineurum
, many species of which can also be found clinging to the wet vertical faces of boulders in the middle of fast moving streams.
Williams (1940)
related the following concerning his observations near Gunnera Springs near Mt. Ka‘ala: “[The genus] appears to favor the steep banks with patchy lights (water, etc., reflections)” ... Though brilliant, it is not conspicuous as it rests head upwards and high on its legs on a dripping wet bank.”
Included species
:
Major minor
(Parent)
*
,
comb. n
.
Etymology
: The genusgroup name derives from the Latin
major
(= large); referring to the extremely large tarsal claws of species in this genus used for clinging to steep, wet, rocky seeps.