Diptera: Empidoidea: Dolichopodidae) from Southeast Asia and Papua New Guinea
Total Page：16
File Type：pdf, Size：1020Kb
Eur. J. Entomol. 102: 107–118, 2005 ISSN 1210-5759 Eothalassius, a new genus of parathalassiine flies (Diptera: Empidoidea: Dolichopodidae) from Southeast Asia and Papua New Guinea IGOR V. SHAMSHEV1* and PATRICK GROOTAERT2 1All-Russian Institute of Plant Protection, Shosse Podbel’skogo 3, 188620 St. Petersburg - Pushkin, Russia; e-mail: [email protected] 2Department of Entomology, Royal Belgian Institute of Natural Sciences, Rue Vautier 29, B-1000 Brussels, Belgium; e-mail: [email protected] Key words. Taxonomy, Diptera, Empidoidea, Dolichopodidae, Parathalassiinae, Eothalassius, new genus, new species, Oriental region Abstract. A new genus of parathalassiine-like flies, Eothalassius gen. n., and two new species, Eothalassius platypalpus sp. n. (type species), E. gracilis sp. n., are described from the coasts of Southeast Asia and Papua New Guinea. The phylogenetic relationships of the new genus with other genera assigned to Parathalassiinae and Dolichopodidae are discussed. INTRODUCTION ming & Sinclair, 2000; Ulrich, 2003). So, any new find- The representatives of the genera joined currently in the ings of unknown representatives of this group would be subfamily (or tribe by authors) Parathalassiinae (Cum- of particular interest. ming & Brooks, 2002; Ulrich, 2003) are mainly very Intensive collections along the coasts of Southeast Asia small and rarely collected flies. They inhabit specific bio- and Papua New Guinea allowed us to obtain new topes of a narrow zone of sea coasts or river banks, materials on Parathalassiinae. The present paper contains including wet and dry parts of sandy beaches, dunes with the description of a new genus including two new species sparse vegetation and wet stones. The subfamily includes of the subfamily. Additionally, the phylogenetic relation- six extant genera: Parathalassius Mik, 1891 (6 species), ships of the new genus are shortly discussed. Microphorella Becker, 1909 (16 species), Plesiotha- Very little is known about the biology and distribution lassius Ulrich, 1991 (2 species), Amphithalassius Ulrich, of Parathalassiinae, including the new genus. 1991 (2 species), Thalassophorus Saigusa, 1986 (1 spe- Parathalassius is only known after a few localities in the cies) and Chimerothalassius Shamshev & Grootaert, Holarctic, including sandy (usually wet beaches) coasts of 2003 (1 species) (Smith, 1972; Saigusa, 1986; Chvála, the Mediterranean and the Pacific Ocean (Chvála, 1988; 1988; Ulrich, 1991; Gatt, 2003; Shamshev, 2003; Sham- Shamshev, 1998). Microphorella has a similar distribu- shev & Grootaert, 2003, 2004). Additionally, four genera tion pattern in the Holarctic, one species occurring in (Cretomicrophorus Negrobov, 1978; Archichrysotus Australia, and four species known in Southeast Asia. Negrobov, 1978; Retinitus Negrobov, 1978; Electro- Microphorella is the only group of the subfamily that is phorella Cumming & Brooks, 2002) described from Cre- found near fresh-water reservoirs, although some species taceous and Baltic ambers were also assigned to this were collected near the sea shore (Melander, 1928; group (Negrobov, 1978; Evenhuis, 1994; Grimaldi & Chvála, 1983, 1988; Gatt, 2003; Shamshev, 2003; Cumming, 1999; Cumming & Brooks, 2002). Shamshev & Grootaert, 2004). Plesiothalassius and Within Empidoidea, this group of genera, together with Amphithalassius are only known from the coasts of the Microphor Macquart, 1827, Schistostoma Becker, 1902, Indian and Atlantic Oceans in South Africa (Smith, 1972; Microphorites Hennig, 1971 and Avenaphora Grimaldi & Ulrich, 1991). Thalassophorus was collected on wet Cumming, 1999, forms a monophyletic lineage with Doli- stones in a rocky beach in north of Hokkaido (Saigusa, chopodidae (Colless, 1963; Hennig, 1970, 1971; Chvála, 1986). Chimerothalassius is known from stony beaches in 1981, 1983; Yeates & Wiegmann, 1999; Collins & Wieg- New Zealand (Shamshev & Grootaert, 2003). mann, 2002). However, the relationships within the MATERIAL AND METHODS lineage are not quite clear yet (Ulrich, 1991; Cumming & This study is based on Diptera materials housed in the Ento- Brooks, 2002). The taxonomic status of this group of mology Department of the Royal Belgian Institute of Natural genera is also a subject of controversies. They were Sciences, Brussels (RBINS). The flies were collected by united into a separate family Microphoridae, including sweeping or in white pan traps (Pollet & Grootaert, 1987) and subfamilies Microphorinae and Parathalassiinae (Chvála, transferred to 75% ethanol. Terms used for adult structures pri- 1983) or were discussed within Dolichopodidae (Cum- marily follow those of McAlpine (1981), although the termi- * Present address: Department of Entomology, Royal Belgian Institute of Natural Sciences, Rue Vautier 29, B-1000 Brussels, Bel- gium. 107 nology for the antenna is taken from Stuckenberg (1999). almost bare basal part), with setulae in apical part longer Homologies for the male terminalia follow Sinclair (2000). To than width of aristal trunk, bearing sensory pit in subbasal facilitate observations, some parts of the body were macerated part, lacking secondary sexual adornments. Proboscis in hot 10% KOH or 85% lactic acid and immersed in glycerine. short, well visible, pointing downward. Palpus large, flat- Drawings of morphological features were made with a camera tened, with secondary sexual differences, lacking basal lucida attached to a compound microscope. In describing the hypopygium, “dorsal” and “ventral” refer to sensory pit. Details of mouthparts as in Figs 7–9. position prior to genital rotation and flexion. Figures showing Labellum well developed, moderately large, produced the male genitalia in lateral view are oriented as they appear on into small lobe at apex. Six geminate inconspicuous pseu- the intact specimen (rotated and lateroflexed to the right). Due dotracheae present, with walls weakly sclerotised. Stipes to inconspicuous setation of these very small flies the term long, slender; lacinia absent. Labrum heavily sclerotised, “bristle” is mainly used for differentiated large setae on the convex basally, with pointed apex; epipharynx with head, mesonotum, and legs bearing a particular name or one of a slender ventral projection, bearing subapical spinules; series with a particular name (e.g. notopleural bristle, dorsocen- epipharyngeal carina elongate; epipharyngeal blades slen- tral bristle, ocellar bristle). der; hypopharynx slender, almost straight; prementum Eothalassius gen. n. with 3–4 short setae on each side; clypeal ridge rather TYPE SPECIES: Eothalassius platypalpus sp. n. short, shorter than cibarium. Thorax with scutum moderately arched, prescutellar Etymology: (Greek) HZ9 = southern, TDODWWD, sea, and TDODVVLR9, belonging to the sea. depression hardly prominent. Prosternum fused with Gender. Masculine. proepisternum. Lateral lobe of antepronotum below post- pronotal lobe and proepisternum with one minute setula Diagnosis. Distinguished from related extant (Paratha- (sometimes lacking). Postpronotal lobe with 1 very short lassius, Microphorella, Plesiothalassius, Amphitha- bristle (additionally, few minute setulae sometimes pre- lassius, Thalassophorus) and fossil (Cretomicrophorus, sent). Mesonotal bristles well-differentiated: one presu- Archichrysotus, Retinitus, Electrophorella) genera by the tural supra-alar (inserted far from postpronotal lobe, often following combination of characters: face very narrow in inclinate and nearly as long as notopleural bristles), 0–1 both sexes, postpedicel very small, style at least five times postsutural supra-alar, two notopleurals, one short post- as long as postpedicel; prosternum fused with proepister- alar and two very long cruciate scutellars (longest among num; wings narrow, anal lobe greatly reduced, costa cir- mesonotal bristles); additionally, one row of 4–6 supra- cumambient, with one row of spinules on anterior margin, alar setulae present. Dorsocentrals 1-serial, three to about vein R1 ending before midpoint of wing, vein CuA2 6–7 per row, with or without accessory setulae. Acrosti- reflexed; male abdominal segments 5–8 modified, hypan- chals minute, few in number, arranged in two irregular drium largely fused with epandrium; female oviscapt with rows or lacking; upper part of vertical anterior surface of setose tergite 10 and slender cerci. scutum with one pair of setulae. Mesopleuron bare. Description. Head broader than thorax in dorsal view, Wing (Figs 12, 13, 25) narrow, 3.0–4.0 times longer broad oval in lateral view, nearly 1.5 times higher than than wide; with anal lobe weakly developed; entirely cov- wide. Occiput more or less rounded, with upper median ered with minute microtrichia (including veins); alula part moderately to strongly concave; insertion of neck absent. Basal section of costa with 3–4 bristles becoming high on head. Eyes dichoptic in both sexes, entirely cov- longer distad; additionally, costa bearing short spine like ered with distinct uniform ommatrichia, with inner mar- bristles and fine hairs along anterior margin and mostly gins not emarginate near antennae; ommatidia large, ciliate along posterior margin (bare near wing base). uniform. Face very narrow (sometimes almost linear) in Pterostigma (or stigmatic sclerotisation) lacking. Costa the middle, slightly widened both above and below. circumambient but strong only along anterior margin up Clypeus very small, somewhat produced below, convex, to short distance beyond apex of R4+5, evanescent along not separated from upper face, rounded apically.