Tethysimyia litophila, Ebejer, 2023

Ebejer, Martin J., 2023, A first account of Chyromyidae (Diptera: Acalyptratae) from continental Central and South America and some Caribbean Islands, with descriptions of new species, Zootaxa 5319 (3), pp. 301-331 : 321-322

Tethysimyia litophila sp. nov.

Figs 13–14

Material: holotype ♁, MEXICO: Chiapas, Puerto Arista , - v.1985, leg. A. Freidberg, (SMNHTAU–419095) . Paratypes: 1♁, 2♀♀, (male headless, dissected), same data and depository as holotype.; 1♁, (abdomen dissected), COSTA RICA: Puntarenas, viii.1980, leg. N.L.H. Krauss ( UZMC) .

Diagnosis: A small species that has ocular microtrichia, pale brown vittae on the scutum, shiny, broad dark brown bands on the abdominal tergite with large round spots on tergite 6 in both sexes. The aedeagus has a broad basiphallus and a relatively short distiphallus compared to congeners.

Description

Male.

Head: all yellow, ocelli reddish brown; frons at vertex about 0.5 width of head, narrowed anteriorly, at level of antennae 0.7 width that at level of anterior ocellus; frons inflated and produced anteriorly above and beyond eye; about 36 pale proclinate setulae scattered on frons; gena narrow in front, deeper behind, in profile, below middle of eye, about 0.8 height of eye, with several, scattered, glistening, pale yellow setulae; occiput in profile narrowly visible behind eye, postocular setulae short, in one row, eye with scattered microtrichia; mouth parts all yellow; 3 short vibrissal setulae about half length of orbital; face short, poorly sclerotized and depressed; median carina developed; antenna yellow, pedicel with distinct short seta dorsally; basal flagellomere with fine pubescence along anterior margin; first segment of arista yellow, second brown; chaetotaxy: 2 short fronto-orbitals, 1 inner and 1 outer vertical, both moderately developed; ocellars broken in holotype, but long and divergent in paratypes, 1 minute divergent pair of postocellars, paraverticals absent; about 36 (50 in females) short pale setulae scattered on frons.

Thorax: pale yellow; scutum with brown patch on lower anterior declivity and 4 broad deeper yellow to pale brown vittae on dorsum; chaetotaxy: 1 postpronotal, 1 presutural intraalar, 2 notopleurals, 2 dorsocentrals, anterior about half length of posterior, 1 postalar, 1 short intrapostalar, acrostichals in 6–8 rows, prescutellars 2 pairs in transverse row, 4 scutellars, 1 anepisternal at middle of posterior margin, 1 katepisternal at upper posterior corner. Some paratypes have a few minute setulae below katepisternal seta.

Wing: veins all pale yellow; distance on costa between R 2+3 and R 4+5 about 0.5 that between R 4+5 and M; distance between cross veins about 2.2 length of posterior cross vein, which lies slightly oblique and is about 0.3 length of apical section of vein Cu. Haltere pale yellow.

Legs: not modified except for pectinate-like setae on ventral surface of mid basitarsomere; numerous pale setulae scattered on all pairs of legs, apico-ventral seta on mid tibia strong; claws black in apical 2/3; hind trochanter not modified.

Abdomen: tergites yellow with subshining dark brown transverse bands dorsally; very few and fine pale setulae except along posterior margins of tergites.

Hypopygium: ( Fig.14 ), epandrium small and pale, bearing a surstylar lobe; cerci small and pale; hypandrium distinct, long and narrow bearing a setulose pregonite posteriorly; phallapodeme long rod-like, postgonites short, apically spatulate and curved dorsomedially; distiphallus pale, weakly sclerotized and narrow apical section longer than broad basal section.

Female: ( Fig. 13D ), differs from male in having a more setulose frons; dorsal vittae more pronounced, being pale brown; abdomen with tergites having narrower brown transverse bands with a triangular extension posteriorly in the midline and the 6 th tergite with a pair of round brown spots leaving the middle clear yellow.

Body length: male 1.2mm, female 1.4mm, Wing length: male 1.0mm, female 1.4mm.

Etymology: the species epithet is a combination of the Latin: litus = coast and the Greek φιλία = friendship (in zoological nomenclature this is taken as affinity or a liking for) refers to the habitat of this species.

Similar species: each of the three species described from the Galapagos has one or more structures similar to the new species. The aedeagus of T. arenicolum ( Wheeler & Sinclair 1994: 443, figs 1–6) is similar, but the pregonite is much larger and longer, the postgonite narrower and shorter; T. litophila differs from T. galamarillum ( Wheeler & Sinclair 1994: 446, figs 7–10) in having a smaller epandrium and proportionately longer hypandrium and phallapodeme; from T. rabida ( Wheeler & Sinclair 1994: 448, figs 11–14) it differs in the shapes of the gonites, phallapodeme and hypandrium.

Distribution: Pacific coast of Costa Rica and Mexico.

Figures

FIGURE 13. Tethysimyia litophila sp. nov,. A. holotype, male. B. same head dorsal view. C. same, hypopygium in situ, posterior view. D. paratype, female, abdomen, posterodorsal view.

FIGURE 14. Tethysimyia litophila sp. nov., paratype, male.A. hypopygium, lateral aspect. B. aedeagal complex, anteroventral aspect. Abbreviations as FIGUREs 2 and 8. Scale bars = 0.15mm.