Argentinomyia praeusta ( Loew, 1866 )

Montoya, Augusto L. & Wolff, Marta, 2023, Taxonomic revision of the Neotropical genus Argentinomyia Lynch-Arribálzaga, 1891 (Diptera: Syrphidae), with description of 16 new species, Zootaxa 5234 (1), pp. 1-157 : 109-112

Argentinomyia praeusta ( Loew, 1866)

( Figs 7E, 65, 66 and 95)

Syrphus praeustus Loew, 1866: 155 . Type locality: Cuba. HOLOTYPE Female MCZ.

Rhysops praeustus . Thompson et al. 1976: 44

Rhysops praeustus . Thompson 1981: 105 (Synonyms and taxonomic notes)

Rhysops quadrimaculata Hull, 1944: 28 . Type locality: Cuba. HOLOTYPE Male MCZ (Examined from Photography). Refs.: Fluke, 1945: 9 (redesc.) 26 ( Fig. 12, head, lateral view, male) 28 ( Fig. 41, male abdomen)

Rhysops quadrimaculata . Fluke, 1945: 9

Rhysops quadrimaculatus . Thompson et al. 1976: 44

Type material. HOLOTYPE. Adult Female , CUBA. Nonspecific locality provided. ( MCZ Cat 23785) . PARATYPE. CUBA. (1♀, MCZ Cat 4162). Wright . DOMINICAN REPUBLIC. Loma Vieja, S. Constanza, 1200 m, viii.1938 (1♁, CNC Diptera ) .

Length (n= 7): Body, 5.4–6.7 mm; Wings, 4.2–4.6 mm.

Diagnosis. Female frontal triangle with a medial white pollinose vitta; metafemur yellow with a black apical ring, metatibia brownish; 3 rd and 4 th terga with maculae extending to the apical 1/2; 5 th tergum without a pair of small lateral rounded maculae; surstylus with dorsal margin slightly concave and ventral margin slightly convex; hypandrium expanded laterally towards the apex; aedeagal lobe circular, apex rounded.

Redescription. MALE. Head ( Fig. 65A): Face brilliantly shining, metallic black, with perhaps a faint bluish luster, mid-vitta, violet, margins are lined by a thin vitta of whitish pubescence. Frontal triangle bluish-black, grey dusted on dorsal half and with a narrow thin line of grey-white pubescence running down the eyes margin which expands anteriorly into a small, triangular spot on dorsal part of the face and again on lower part of the face opposite the tubercle, the lower half of face sparsely white pubescent and diagonally striate opposite the tubercle; the middle of the face is cut by four shallow grooves, the outer ones less distinct; Pile of the face and frontal triangle light brownish-yellow, of vertex darker; the vertical triangle small, the occiput not protruding beyond the eyes on dorsal 1/3. Antennae yellowish, short, ratio 1.2:1.3:16, darker toward the end and dorsal on basoflagellomere; scape and pedicel nearly equal in length; light brownish-yellow; arista yellow at base and dark on apical third, with pile short. Thorax ( Figs 65B–C): Very convex, shining metallic black; with three brownish pollinose vittae, the median run halfway down the posterior part of mesonotum, there are suggestions of the fourth pair of such vittae lying some distance from the others on lateral part of mesonotum. There is a low but well-developed, rounded bump in the middle of the anterior lateral corners of the thorax lying diagonally from the humeri. Pleura grey shining, whitish pollinose, yellow whitish pilose. Scutellum broadly rounded, brilliantly metallic, with two or three subterminal, transverse, faint, ripple-like depressions; fringe long. Wing ( Fig. 65C): Very lightly tinged with brown, stigma brownish, microtrichose, except cell c bare on basal 2/3, cells bm and r bare on basal 2/3, cell cua bare on anterior 3/5, the apical margin of the wing to just past the end of third vein marginate with brown, giving the impression of an elongated brown macula; calypter yellow, border and fringe dark brown; plumula white; halter yellow, capitulum yellowish. Legs ( Figs 7E, 65C): Almost wholly pale brownish-yellow; metafemur obscured on apical 1/3 or little more; metatibia and metatarsus obscurely dark except the indefinite base, metatarsus and three basal tarsomeres yellow, another tarsus dark brown. Abdomen ( Fig. 65B): Long and slender, rather flattened, sides almost parallel, end of 3 rd tergum barely wider than the base of abdomen; 1 st tergum shining metallic black, 2 nd shining on basal 2/5 with a brassy or golden, brown appearance; opaque, dark sepia-brown on almost all of the remaining segments and quite to their posterior margin. Located near the base upon sides of 2 nd tergum, not reaching the anterior corners and covering about 1–1/2 the segment length there are shallow, diffuse, brownish-yellow maculae; in some specimens, it extends inward for a greater distance. 3 rd tergum with a pair of large, square, light brownish-yellow maculae occupying the base, the entire anterior corners and the sides for 1/2 the segment length; their medial surfaces are just a little cut-away and diminished on posterior surfaces; the remainder segments opaque, dark sepia. 4 th tergum with a pair of similar maculae, slightly smaller, barely darker and a very little closer together; the remainder of that segment shining black. The pile upon abdomen seems to be practically absent on 3 rd and 4 th terga. The sparse lateral pile of 2 nd is pale; male genitalia: surstylus in lateral view ( Fig. 66A) with dorsal margin slightly concave and ventral margin slightly convex; hypandrium in ventral view ( Fig. 66C) expanded laterally towards the apex; aedeagal lobe in ventral view ( Fig. 66C) circular, apex rounded.

FEMALE ( Figs 65D–F). Similar to male except for usual sexual dimorphism and differing in Abdomen opaque black, more shining on sides with a pair of quadrate yellow maculae in the basal marginal corners of 3 rd and 4 th terga, slightly wider on margin and reaching nearly to the apical 1/2. The female of A. praeusta is similar in appearance to A. jamaicensis sp. nov., differing by the following combination characters: Female frontal triangle with a medial white pollinose vitta; metafemur obscured on apical 1/3 or little more; 3 rd and 4 th terga with maculae extending to the apical 1/2; 5 th tergum without a pair of small lateral rounded maculae; metafemur yellow with a black apical ring, metatibia brownish.

Taxonomic notes. Argentinomyia praeusta differs from A. aurifacies sp. nov. and A. taina sp. nov. by having the female frontal triangle with a medial white pollinose vitta ( Figs 65D, F); metafemur yellow with a black apical ring, metatibia brownish ( Figs 65A, C, D, F); 3 rd and 4 th terga with maculae extending to the apical 1/2; 5 th tergum without a pair of small lateral rounded maculae ( Figs 65B, E). In Argentinomyia aurifacies sp. nov. the face extensively covered by golden pollinose and pilose ( Figs 14A, C, D, F); female frontal triangle with a transversal goldenbrownish pollinose band ( Figs 14D, F); metafemur yellow, only obscured on basal 2/6 and apical 1/6 or little more ( Figs 14A, C, D, F). In Argentinomyia taina sp. nov. the frontal triangle with transversal golden-brownish pollinose band touching slightly the sides of the eyes ( Figs 77A, C, D, F); metatibia mostly brownish apically, yellow basally and slightly obscured on apical 1/5 dorsally ( Figs 77A, C, D, F); 3 rd and 4 th terga with maculae extending to the apical 2/3; 5 th tergum with a pair of small lateral rounded maculae ( Figs 77B, E). Based on males, A. praeusta differs from A. aurifacies sp. nov. and A. taina sp. nov. in having the surstylus in lateral view ( Fig. 66A) with dorsal margin slightly concave and ventral margin slightly convex [versus surstylus with dorsal and ventral margins approximately of the same width in the whole length in A. aurifacies sp. nov. ( Fig. 15A); surstylus very elongated and widened dorsally, with a small extension at the ventral margin in A. taina sp. nov. ( Fig. 78A)]; hypandrium in ventral view expanded laterally towards the apex in A. praeusta ( Fig. 66C) and A. taina sp. nov. ( Fig. 78C) [versus hypandrium narrowed laterally towards the apex in A. aurifacies sp. nov. ( Fig. 15C)] (see “diagnosis” under each species or key).

Remarks. Thompson (1981) compared the type of Rhysops praeusta (MCZ: https://mczbase.mcz.harvard.edu/ name/ Syrphus %20praeustus) and R. quadrimaculata (MCZ: https://mczbase.mcz.harvard.edu/name/ Rhysops %20q uadrimaculata) and found that they corresponded to opposite sexes of the same species (conspecific) with the pile of male brownish, abdomen narrower, with large, quadrate maculae, sides of 2 nd tergum shiny. He concluded that these are typical of sexual dimorphism found in other species of the genus, therefore, formally synonymized Rhysops quadrimaculatus under Rhysops praeustus .

Geographical range. Argentinomyia praeusta (n= 24) is endemic to the West Indies and widely distributed in Cuba (Camagüey), Serra de Bahruco / Massif de la Selle and the Cordillera Central, Cordillera Septentrional in the Dominican Republic* (Independencia, La Vega, La Vega, Pedernales) and the Blue Mountains in Jamaica * (Portland Hardward) ( Fig. 95). The species is endemic to the West Indies domain at middle altitudes (1100–2400 m) , widely distributed in the provinces: Cuban (1100 m), Jamaica (1120 m) and Hispaniola (1200–2400 m).

Non-type material examined. CUBA. Camagüey, Nonspecific locality provided. 21,521 757, -77,781167, 1100 m, Wright (1♁, MCZ) . DOMINICAN REPUBLIC. Independencia, Road 47, between Los Pinos and Ángel Félix , 18,743 411, -71,675054, 700 m, 20.vi.2005, N.E. Woodley (1♀, USNM ENT 01443771 ) ; near Serra de Baoruco National Park , 3.5km El Aguacate, Montane meadow, 18,166 667, -71,416667, 2210 m, 30.ix.1991, C. Young; S. Thompson; R. Davidson; J. Rawlins (1♁, USNM ENT 01443776 ) ; La Vega, Sabana Kelly (= Quéliz) Valle Nejeno , 18,750 116, -70,616826, 2294 m, 2.iv.2003, D. Pérez, R. Bastardo; B. Hierro (2♁, 6♀, USNM ENT 00038429–36 ) ; Trail to Peak and Centro SOECI, Pico Diego de Campo , 19,580 523, -70,740457, 918 m, RD-184, 4.ii.2003, D. Pérez, R. Bastardo; A. Marmolejos (3♁, 3♀, USNM ENT 00038437–42 ) ; La Compartición, Pico Duarte, P. N. Armando Bermúdez, 19,025 337, -70,99825, 3087 m, RD-255, 7.i.2004, D. Pérez (2♁, USNM ENT 00038439 ; 0003843) ; Pedernales, 9.7km NE, los Arroyos , 18,823 174, -70,832299, 2070 m, 15.vii.1990, J. Rawlins, C.W. Young; S.A. Thompson (1♀, USNM ENT 01443777 ) . JAMAICA. Portland Hardward Gap , 18,068 139, - 76,636 631, 1120 m, 5.vi.1965, T.H: Farr (1♀); 19.vii.1966, Howden; Becker (1♀, CNC DIPTERA 112214 ) .