Schizonyxhelea zoologica, Huerta & Grogan, 2017

Huerta, Herón & Grogan, William L., 2017, New species and new records of predaceous midges in the genera, Schizonyxhelea Clastrier and Stilobezzia Kieffer from Mexico (Diptera: Ceratopogonidae), Zootaxa 4294 (4), pp. 401-418 : 404-407

Schizonyxhelea zoologica new species

(Figs. 1–7, 24)

Diagnosis. Male: The only New World species of Schizonyxhelea with three distinctive crenulations on the mesal surface of the gonostylus. Female unknown.

Male. Head (Fig. 1). Light brown; vertex and dorsal portion of occiput darker brown. Eyes moderately separated, with sparse very short interommatidial spicules Antenna (Fig. 2) with dark brown pedicel; flagellomeres 1¯9, proximal half of 10 pale brown, distal half of 10, 11¯13 darker brown; flagellomeres 1¯4 separate, 5¯9 or 5¯10 fused, 11¯13 separate, greatly elongate; flagellomeres 1¯10 with long sensilla chaetica comprising the moderately dense plume; antennal ratio 0.93¯1.02 (0.96, n=3). Mouthparts short, light brown. Palpal segment 3 moderately long, with a few capitate sensilla on apicomesal surface; segment 4 very short; segment 5 moderately elongate, nearly as long segment 3; palpal ratio 2.55¯2.80 (2.63, n=3). Clypeus with 3 pairs of submarginal setae. Thorax. Brown. Scutellum light brown, with 2 marginal, 2 central setae. Paratergite without seta, with lateral suture; anepisternum well developed, not bilobed posteriorly; pleura without setae. Legs (Figs. 3a–c) with mid, hind coxae dark brown; fore coxa, trochanters medium brown; femora light brown, hind femur with large darker brown sub-apicodorsal patch; tibiae, tarsi light brown; tarsomeres 1¯2 of fore, mid legs with one row, tarsomeres 1¯2 of hind leg with two rows of ventral palisade setae; hind tibial comb with 6 spines, 2nd from spur longest; claws moderately short, stout, equal-sized, slightly curved with small basal seta, tips bifid. Wing (Fig. 4) membrane hyaline, surface covered with fine microtrichia only; macrotrichia restricted to margins of costa, wing membrane, 1 on base of R1, 1¯2 over 1st radial cell, 1¯3 on R3; costa, radius, base of vein M1 light brown, posterior veins very pale; 1st radial cell very small, 2nd radial cell 3.4 x longer than 1st; wing length 0.91¯0.98 (0.95, n=3) mm, breadth 0.31¯0.33 (0.33, n=3) mm; costal ratio 0.59¯0.60 (0.59, n=3) mm. Haltere light brown; distal portion of knob pale. Abdomen ( Fig. 7 ). Tergite 1, sternites 1¯8 pale; tergites 2¯8 mostly dark brown, darker than remainder of body except tergites 2¯4 with anteromedial areas pale. Genitalia ( Figs. 5–7 ). Tergite 9 tapering gradually distally to rounded apex that extends below or to apices of gonocoxites; sternite 9 very short, reduced to narrow band with a nearly straight anterior margin, posterior margin slightly concave; tergite 10 with greatly elongate setose, slightly divergent cerci that extend below or to level of 2nd crenulation of gonostylus. Gonocoxite nearly straight, twice as long as broad, covered with fine setae and sparse scattered large setae borne on rounded tubercles. Gonostylus 0.7 FIGURES 1–4. Schizonyxhelea zoologica n. sp. Male. 1. Head, frontal view. 2. Antenna, lateral view. 3. Legs, lateral view. 3a. Fore leg. 3b. Mid leg. 3c. Hind leg. 4. Wing. Abbreviations: II–V = palpal segments, Ped = pedicel, X–XIII = flagellomeres, Cx III = coxa, Tr = trochanter, Fe = femur, Ti = tibia, Ta I–V = tarsomeres of hind leg. Scales: 0.1 mm.

length of gonocoxite, covered with fine setae; outer margin nearly straight; medial surface with 3 crenulations, proximal 2 rounded, apical 3rd projection with subapical medial portion concave with a tapered, sharply pointed apex; posteromedian surface heavily sclerotized with row of 3 large setae, apex roundly pointed, formed by junction of concavity of distoventral portion of outer surface. Parameres ( Figs. 5–6 ) divided, heavily sclerotized; each half rod-like, proximal ¾ sub-parallel, distal ¼ cross each other, apices with sharply pointed tips extending beyond base of gonostylus; gonocoxal apodemes heavily sclerotized, curved, distal 2/3 moderately broad, connected to ventral root of gonocoxite, proximal 1/3 tapered to narrow basal portion that is fused to lateral subbasal portion of parameres. Aedeagus ( Fig. 5 ) greatly reduced, enclosed in a thin, barely visible, hyaline envelope; basal margin concave, apical margin rounded; basal portion with straight, moderately sclerotized remnants of basal arms with an underlying heavily sclerotized, crescent-shaped dorsomedial sclerite.

Distribution. Mexico (Tabasco) ( Fig. 24 ).

Etymology. The specific name (a noun in apposition) of this unusual new species is a reference to the type locality, in the Zoological Park section of the city of Villahermosa, Tabasco, Mexico.

Type material. Holotype male, MEXICO, Tabasco, Villahermosa , Centro, Zoológico, 23 dic-2008 al 8-enero- 2009, Trampa Malaise, A. Villanueva. Paratypes, 5 males: 2 males with same data as holotype (1 in CAIM; 1 in FSCA) ; 3 males, Cunduacán, Huimango, 2da. Sección, 27–28-Jun-2006, en cacaotal, Trampa Malaise, A. Godínez-Álvarez (CAIM).

Discussion. Males of Schizonyxhelea zoologica are similar to males of S. thomsenae and S. bulla in size, dark coloration of their hind femur, fused flagellomeres 5¯9 or 5¯10; moderately separated eyes with very small interommatidial spicules; and a wing with a very small 1st radial cell. Both of those species have similar genitalia, in particular the shapes of their gonostyli, parameres and aedeagus. However, both species are readily distinguished from males of S. zoologica in having simple, slender gonostyli without medial crenulations.

A paratype from the type locality has laterally mounted genitalia, but, is missing a gonostylus, and the remaining gonostylus is greatly deformed. This deformed gonostylus lacks the proximal two rounded crenulations, and therefore, it is straight with parallel margins, but shorter than normally shaped gonostyli of the holotype and other paratypes. In addition, the distal portion of this deformed gonostylus is very broad and club-shaped, which may be possibly due to a fusion of the 2nd crenulation and the angular apical crenulation.

Figures

FIGURE 24. Distribution of Schizonyxhelea zoologica n. sp. (solid rectangles), and Stilobezzia (Acanthohelea) spinellii n. sp. (solid circles) in Mexico.

FIGURES 5 – 7. Schizonyxhelea zoologica n. sp. Male. 5 – 6. Genitalia, ventral view. 7. Abdomen and genitalia (ventral view). Abbreviations: aed = aedeagus, cerc = cercus, goncx = gonocoxite, goncx apod = gonocoxal apodeme, gonsty = gonostylus, pm = parameres, pm b apod = paramere basal apodeme, St 9 = sternite 9. Scales: 0.04 mm.