Sigmatineurum puleloai Englund & Evenhuis, 2005

Englund, R. A. & Evenhuis, N. L., 2005, Sigmatineurum puleloai (Diptera: Dolichopodidae), a new species from Pelekunu Stream, Moloka‘i, Hawaiian Islands, Zootaxa 1017 (1), pp. 33-37 : 34-36

Sigmatineurum puleloai Englund & Evenhuis , sp. nov.

( Figs. 1–4 )

Sigmatineurum new sp. Englund 2001: 3, 4; Englund and Arakaki 2003: 3, 6

Diagnosis. This species keys to S. parenti using the key to species in Evenhuis (1997), but midleg setation differs with S. parenti lacking strong bristles on middle ventral section of the midleg femur while S. puleloai has 4–5 strong bristles. The m­cu crossvein in S. parenti is slightly more curved compared to the relatively straight m­cu crossvein of S. puleloai . The sternal 4 process on S. puleloai is flattened and not peg­like as in S. parenti .

Sigmatineurum puleloai differs from other species by the combination of a flattened process on sternite 4, U­shaped pollinose brownish­black markings on the dorsolateral portions of the abdominal tergites, and the midleg setation (MSSC). In addition, S. puleloai can be distinguished from its congeners by having the mesal setae of IIt1 subequal in size throughout its length (these setae longer and denser at the base in all other species).

Description. Male. Body length: 4.6 mm. Wing length: 4.5 mm. Head. Front, face, and vertex dark brown with dark green reflections; occiput dark brown; clypeus dark brown, palp and proboscis dark brown; antenna with arista length slightly less than head height. Postocular hairs uniseriate, strong bristles extending to ventral section of head, lacking ventral hairy or fuzzy appearance ventrally.

Thorax. Mesonotum and scutellum dark, bluish green, notopleural area shining greenish­orange; anepisternum with bright metallic green; remainder of pleura light brown; thoracic setae black; 4 dc; 2 np; 1 ph; 1 sc; 2 sa, 1+1 hu;1 pa.

Legs. Coxae metallic greenish orange, distal half becoming dull brownish. Femora and tibia with light green and orange reflections, uniformly colored in contrast to darker distal portion of coxae. Trochanters pale yellow. Blue­green with orange undertone reflections on coxae, femora, and tibia. FI with long regularly spaced bristles ventrally; remain­ der of leg I unmodified. FII ( Fig. 3 ) swollen on basal 1/3; longer bristles (MSSC) in middle ventral section of femur, base and apex with shorter bristles. Two strongly curved bristles near apex of femur, but shorter than the long bristles in the middle ventral section of the femur. TII enlarged slightly toward apex. One strong black setae curving downward at apex near basitarsus, another strong setae near base extending laterally ( Fig. 3 ); IIt1 twice length of IIt2, with mesal setae all same length ( Fig. 3 ). Remainder of leg II unmodified. Leg III with strong bristles evenly spaced on femur, bristles similar in size and shape to those on TII, with tibia and tarsi unmodified.

I—26.0; 25.0; 12.0/4.0/3.0/2.0/3.0

II—29.0; 39.0; 12.0/4.0/3.0/2.0/3.0

III—29.0; 39.0; 21.0/10/6.0/5.0/5.0

Wing. Subhyaline throughout, pale brown color strongest at extreme base; m­cu crossvein similar to S. englundi Evenhuis but slightly more bent; CuA 1 reaching wing margin; halter pale brown. Wings lacking infuscations on distal portions of radial and medial veins.

Abdomen. Bright metallic blue­green with dark brown pollinose patches dorsolaterally on tergites 3, 4, and 5 not quite extending to extreme lateral margin; sternite 4 process ( Fig. 4 ) a rather broad and flattened projection.

Genitalia. Not dissected. Hypopygium a dark, brassy–green color.

Female. Bright metallic blue­green, similar to male except lacking distinctive dorsolateral brown abdominal tergite patches and leg MSSC.

Types. Holotype ♂ ( BPBM 16,562 ) from HAWAIIAN ISLANDS: Moloka‘i: Pilipililau Stream (tributary to Pelekunu Stream) 170 m, 23.v.2001, R. Englund, rheocrene seep habitat . Paratypes: 2 ♀♀, same location and date , 1 paratype ♀ same data except collected 29.v.2002 (all in BPBM) .

Habitat. This species was collected during sweep­net sampling of a large rheocrene seep area along Pilipililau Stream (a small tributary to Pelekunu Stream), and also in a cascade­like chute found upstream of a large seep wall. Altogether, this habitat is no more than 30 m long. Pilipililau Stream was sampled upstream of the trail connecting the TNCH Papa‘iki Camp to a U.S. Geological Survey gauging station. This habitat is located at approximately 170 m elevation and was sampled upstream to a 3 m high bedrock stairstep cascade, which also provided a small amount of splash­zone habitat. Immediately downstream of this cascade was a 12–15 m high mossy slope running along the northern face of the tightly incised Pilipililau Stream channel. A small amount of water dripping on the canyon wall (downstream of the cascade) created a rheocrene seep covered by a light green species of algae from which adult S. puleloai were collected. This species is apparently restricted within the Pelekunu watershed and it has only been captured in low numbers at the one favored rheocrene seep.

Etymology: The specific name is named in honor of Hawaii Division of Aquatic Resources biologist William Puleloa for his efforts and leadership in the conservation of the unparalleled native Hawaiian stream organisms found on Moloka‘i, and for his organization of surveys that led to the discovery of this aquatic insect.

Figures

FIGURES 1–4. Sigmatineurum puleloai, n. sp. 1. Male habitus, lateral view. 2. Detail lateral view of abdomen showing dark pollinose areas of tergites. 3. Male mid leg (femur, tibia, and first tarsal segment) showing setation. 4. Sternite 4; a. caudal view; b. lateral view (right side).