Parathalassius abela Cumming 2017, sp. nov.
Creators: name: Cumming, Jeffrey M.
Publisher: name: Zenodo
Year: 2017
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Diptera
Dolichopodidae
Parathalassius
Parathalassius abela

description: Parathalassius abela sp. nov.
(Figs 1–4, 23–24, 38, 56, 80, 95–96, 115, 133, 142)
Type material. HOLOTYPE ♂ labelled: “USA: CA: Santa Barbara Co.:/ Surf Beach, Vandenberg Air / Force Base, 34.683801°N / 120.605520°W, 6.iv.2016 / A.J. Abela, ex: Ambrosia / chamissonis on coastal dunes”; “ HOLOTYPE / Parathalassius abela / Brooks & Cumming [red label]” (CNC). PARATYPES: USA: California: same data as holotype (42♂, 34♀, CNC); same data as holotype except, 21.iii.2016 (18♂, 8♀, CNC; 2♂, USNM); same data except CNC588227 (1♂, barcoded, CNC), CNC588228 (1♀, barcode-associated, CNC); same data as holotype except, 5.iv.2016 (2♂, 1♀, CNC).
Other material examined. USA: California: Monterey County: Marina dunes [ca. 36°41′33″N 121°48′38″W], 22.v.1982 (12♂, 6♀, EMEC); Salinas River State Beach [ca. 36°46′33″N 121°47′50″W], 26.vii.1994, sandy beach, H. Ulrich (3♂, ZFMK); same data except, dunes (3♀, ZFMK); same data except, 27.vii.1994 (8♂, 8♀, ZFMK); Santa Barbara County, Surf Beach, Vandenberg AFB, 34.683801°N 120.605520°W, 4.vi.2016, ex: Ambrosia chamissonis & coastal dunes, A.J. Abela (6♂, 19♀, CNC); same data except, S.E. Brooks (23♂, 24♀, CNC; 2♂, 2♀, CSCA); same data except, CNC573323, CNC573299 (2♂, barcoded, CNC), CNC573298, CNC573301 (2♀, barcode-associated, CNC); same data except, J.M. Cumming (26♂, 56♀, CNC); same data except, CNC582818, CNC582864 (2♂, barcoded, CNC), CNC582808, CNC582832 (2♀, barcodeassociated, CNC); same data except, S.H. Cumming (2♀, CNC); San Luis Obispo County, Morro Bay, dunes nr. Morro Rock, 35°22′16.4″N 120°51′52.0″W, 3.vi.2016, swept sandy seacoast & beach vegetation, S.E. Brooks (11♂, 4♀, CNC); same data except CNC573213, CNC573203 (2♂, barcoded, CNC), CNC573207, CNC573212 (2♀, barcode-associated, CNC); same data except, J.M. Cumming (2♂, CNC); same data except CNC5 80878 (1♂, barcoded, CNC); Morro Bay, 30.iv.1962, C.A. Toschi (1♂, EMEC); same data except, P.D. Hurd (1♀, EMEC); same data except, 26.iv.1968, P.A. Opler (1♂, EMEC); same data except, 16.vi.1947, A.L. Melander (2♀, USNM); Morro Dunes, 17.vi.1947, A.L. Melander (1♀, USNM); Oso Flaco Dunes [35.032931°N 120.629882°W], 8.iii.2015, A. Abela (1♀, photograph, see Fig. 1 D).
Diagnosis. This relatively large species is characterized by 3–4 notopleural bristles, dark legs, relatively long vein CuA+CuP, males with golden-yellow pruinosity on the face and clypeus, and longer lower male ommatrichia. Parathalassius abela is very similar to P. candidatus, but males can be distinguished by the golden-yellow pruinosity plus yellow setae and ommatrichia on the lower part of the head. Females of these two species are virtually identical.
Description. Male (Figs 1–3): Body length 2.4–3.3 mm, wing length 2.7–3.2 mm. Dark brown ground colour covered mostly with dense greyish-white pruinosity. Setae of body and legs generally white. Head (Figs 1, 3, 23): Eyes with ommatrichia of lower third distinctly longer and slightly flattened, forming dense reflective mat of yellowish coloured hair. Face and clypeus covered with golden-yellow pruinosity (apparently faded in some specimens through preservation), not concolourous with greyish-white frons and vertex. Face narrowest at middle, about 2.0X width of anterior ocellus. Gena and postgena with moderately long pale yellowish setae, forming short beard flanking mouthparts. Antenna (Fig. 38) including arista-like stylus, entirely dark brown; postpedicel subtriangular, 1.5–1.7X longer than wide; arista-like stylus long, about 2.0X length of postpedicel. Palpus with 2–3 moderately long setae and several short setulae on outer surface of apical half. Thorax: Acrostichal setulae quadriserial; 6–7 dorsocentral bristles, 0–1 presutural intra-alar bristles, 1–2 presutural supra-alar (posthumeral) bristles, 2–3 postsutural supra-alar bristles, 3–4 notopleural bristles. Scutellum with 3 pairs of bristles. Legs: Foreleg: Dark grey, pale only at knee. Coxa with moderately long pale white to yellowish setae on anterior surface. Femur with numerous long setae on posterior surface, posterodorsal and posteroventral rows prominent. Tibia with short setae and setulae. Tarsus with setulae; tarsomeres 1–2 not dilated. Midleg: Dark grey, pale only at knee, tarsus greyish-brown. Femur with anteroventral and posteroventral row of setae prominent. Tibia with pair of apicoventral bristles. Tarsomeres 1–4 each with pair of dark spine-like apicoventral setae. Hindleg: Dark grey, femur dark brown posteriorly, tarsus greyish-brown. Femur with ventral row of setae prominent. Tibia with anterodorsal and anteroventral rows of setae prominent, subequal or longer than width of tibia, with anterodorsal row of setae not or barely curved towards apex of tibia. Tarsus slightly shorter than tibia with short setae and setulae; tarsomere 1 slightly shorter than combined length of tarsomeres 2–4; tarsomeres 2–3 with some slightly thickened angled setae dorsally, not perpendicular and peg-like; tarsomere 2 distinctly longer than tarsomere 3; tarsomere 3 slightly longer than tarsomere 4; tarsomere 5 subequal in length to tarsomere 3. Wing (Fig. 56): Hyaline with dark brown veins. Cell dm produced apically, dm-m crossvein concave. Vein CuA+CuP relatively long, slightly curved to straight. Abdomen: Tergites 2–4 with setae well-developed and relatively long. Sternite 5 with slender anteriorly curved digitiform pregenitalic process present, base with short blunt anterior projection, apex blunt and covered with microtrichia, posterior edge of sternite 5 (behind process) deeply emarginate. Sternite 8 subquadrate, with prominent elongate setae on posterolateral margins. Hypopygium (Figs 80, 95–96, 115): Large. Left epandrial lamella with ventral portion elongate (about 2X longer than high); ventral epandrial process broadly bifurcate, dorsal arm curved ventrally, narrow in middle portion, apex expanded and hook-like, ventral arm thick with minute apicodorsal seta and pair of minute setae along distiventral margin, apex with expanded lamelliform concavity. Dorsal lobe of left surstylus subtriangular with basiventral edge weakly rounded, with long basidorsal seta, short lateral seta and long apical seta, medial surface with knob-like projection bearing lamelliform apical process. Ventral lobe of left surstylus shallowly bilobate in lateral view, dorsal lobe short with apex subquadrate, ventral lobe with rounded base bearing short lateral seta and complex upturned multilobate projection arising medioventrally. Right epandrial lamella with ventral epandrial process not developed; basal portion of epandrial lamella narrowed and dorsally curved, with deep dorsal emargination bordering ventral margin of right cercus. Dorsal lobe of right surstylus with 3 lateral setae (apical-most seta somewhat stronger), apex narrowed with squared-off tip bearing thick apically-frayed prensiseta on medial surface. Ventral lobe of right surstylus with lateral seta near middle, distal half recurved and tapered with tubercle bearing strong seta proximal to rounded apex. Hypandrium very large, elongate-reniform with convex anterior and posterior ends extending to or beyond margins of epandrial lamellae in lateral view, mainly bare except for a few short setae lateroventrally on left side, and posteriorly on right side. Left postgonite lobe subquadrate basally, constricted near middle, with distal portion broadly lamelliform with claw-like apical process, base of lobe with slender medial projection. Right postgonite lobe with broad lateral protuberance and bulbous medial projection, apex bifurcate with short digitiform process and rounded lamelliform process. Phallus short and weakly curved, broad in basal 2/3 with apical 1/3 narrower (in lateral view), dorsal flange and left lateral bump-like protuberance present at 2/3 length. Ejaculatory apodeme broadly subtriangular. Hypoproct strongly projected dorsally as pair of slender blade-like lobes. Cerci with anal setae well-developed and differentiated from surrounding hairs; right cercus much larger than left cercus with basal portion distended and rounded laterally, apex strongly deflected dorsally, elongate narrow and pointed with 2 short preapical setae on lateral margin; left cercus oblong-subrectangular in dorsal view, apex short and truncate, with 2 long, dorsally-directed setae.
Female (Fig. 4): Body length 2.7–4.3 mm, wing length 2.9–3.8 mm. Similar to male except as follows: Head (Fig. 24): Eyes with ommatrichia of nearly uniform length, not distinctly longer on lower third. Face and clypeus without golden-yellow pruinosity, concolourous with greyish-white frons and vertex. Face wider, at middle about 4.0X width of anterior ocellus. Legs: Foreleg: Coxa with shorter more slender pale white setae on anterior surface. Femur with posteroventral row of setae only prominent apically. Midleg: Femur with anteroventral and posteroventral setae less prominent. Hindleg: Tarsomeres 2–3 without slightly thickened setae dorsally. Abdomen: Tergite 5 broadly subtriangular to semicircular in dorsal view with posterior margin rounded (cf. Fig. 131).
Terminalia distinctly narrower than base of segment 5 (cf. Figs 131–132); sternite 8 trough-like, lacking basal bulge, widened just beyond base and narrowed apically, apical half with longitudinal ridges, apex broadly truncate (Fig. 133); sternite 9 reduced to a narrow transverse sclerotized band; tergite 10 with hemitergites subtriangular and short, each with 2 acanthophorite spines; cercus short, pointed apically.
Distribution and seasonal occurrence. Parathalassius abela is currently known only from coastal dunes in Monterey County, San Luis Obispo County and Santa Barbara County, in southern California (Fig. 142). Adults have been collected or photographed from early March to late July.
Etymology. The species name honours Alice Abela (Santa Barbara County) (Fig. 20), who first alerted us to the existence of this species, as well as P. infuscatus sp. nov. and P. uniformus sp. nov., through her excellent photographs of these flies and subsequent collection of specimens of all three previously unknown species.
Remarks. COI barcode sequences (Fig. 154) and morphology confirm the separation of this species from the very similar allopatric P. candidatus (with minimally 3.6% genetic divergence). A small degree of genetic divergence (minimally 1.1%) between populations of P. abela on Surf Beach and Morro Bay, suggests some isolation of the two populations of this species on these nearby beaches (45 km apart).
Adults of P. abela were frequently found towards the back of the fore dune beach habitat on the leaves of beach bur (Ambrosia chamissonis (Less.) Greene) (Fig. 20).
description: Published as part of Cumming, Jeffrey M., 2017, Revision of the Nearctic Parathalassius Mik (Diptera: Dolichopodidae: Parathalassiinae), with a review of the world fauna, pp. 1-64 in Zootaxa 4314 (1) on pages 13-15, DOI: 10.11646/zootaxa.4314.1.1, http://zenodo.org/record/858378