Lenkoa phillipei, Brown, Brian V. & Porras, Wendy, 2016

Brown, Brian V. & Porras, Wendy, 2016, A second species, and first Central American record, of the phorid fly genus Lenkoa Borgmeier (Diptera: Phoridae), Zootaxa 4168 (3), pp. 583-588 : 583-587

Lenkoa phillipei new species

Figs. 1–4 , 6 .

Diagnosis. T his species differs from L. aurita by the less-developed lateral head ridge, much longer wing rudiments, and the long narrow abdominal sclerite ( Figs. 4–5 ).

Description. Female. Body length 2.10–2.25 mm. Body color light brown. Frons with numerous medium-sized setae, making recognition of typical phorid setation difficult, but recognizable are one pair of divergent, proclinate supraantennal setae, slightly medioclinate ventral and dorsal interfrontal setae, pair of postocellar setae, and inner vertical setae, but many additional near-bristle-sized setae are found on the frons and vertex. Eye greatly reduced. Posterolateral head ridge present. Thorax highly modified, reduced. Proepisternum relatively large, with several uniform setae. Posterior portion of anepisternum present; anterior portion almost completely absent; both without setae. Mesopleural suture nearly completely fused, minor sclerites around wing base absent or fused. Anepimeron quadrate, with three large setae. Katepisternum greatly elongate, protruding moderately into dorsal sclerites, with several widely spaced setae. Posterior to katepisternum, dorsal to midcoxa and hind coxa, with rounded, short sclerite, potentially composed of meron plus some other ventral sclerites. Posterior spiracle in large sclerotized area, probably composed of sclerites, plus sclerotization of usual membrane surrounding spiracle. Hind coxa with scattered long setae. Scutum with long, sparse setae. Scutellum short, posteriorly truncate, without setae. Wing reduced to long rudiment. Halter absent. Legs elongate, cylindrical, sparsely setose. Abdomen white; with sparse setae and reduced tergites. Tergite 2 elongate, narrow, tergite 4 fused to sclerotized gland opening. Segments 3–4 dorsally short, 5 anteriorly protruding. Segment 6 long; abdomen posterior to segment 6 extremely short, with only the U-shaped sclerite with long anterior arms ( Brown 1992a) and normal cerci present.

Natural history. Unknown, as the specimens were collected in an emergence trap; however, one of us (WP) noted large numbers of termites in the wood over which the trap was placed. The wood was various small tree branches, some of which were in water, and some of which were dry.

Derivation of specific epithet. Named for one of the grandchildren of Jorge Arturo Lizano, owner of the Zurquí property, who graciously allowed us to operate our project in this remarkable forest.

Holotype. ♀, COSTA RICA: San José: Zurquí de Moravia, 10.05°N, 84.01°W, 1600 m, emergence trap, ZADBI- 721, #106726 ( MNCR).

Paratypes. 3♀, same data as holotype ( MNCR, LACM).

Possible male specimens. In addition to the females described herein, 16 males that we classify as belonging to the Metopina -group of genera (Brown 1992), were found in the same sample. In the latest key to phorid genera ( Disney 1994), these males key to the second lead of couplet 217, along with a few other genera of brachypterous to apterous antassociated phorids whose males have neither been sufficiently differentiated nor associated with their corresponding females. These males would key similarly key to the second lead of couplet 104 in the Manual of Central American Diptera key to phorid genera (Brown et al. 2010), which is also a dead end for several Metopina -group genera. Although these specimens potentially are the males of Lenkoa phillipei , we have no decisive data to make this claim. We briefly describe and illustrate them herein to facilitate their future recognition.

Brief description of male ( Fig. 6 ). Body length 1.9 mm. Color dark brown, except legs and katepisternum light brown. Frons short, not strongly projecting between antennae, with 4 long, porrect supra-antennal setae, and 2-4-4 frontal setae (ventral fronto-orbital setae absent). Eye, palpus and ocelli large. Thorax with 4 notopleural setae; proepisternum with several moderately large setae, with most ventral longest; anepisternum bare. Wing ( Fig. 7 ) with C longer than one-half wing length (0.54); costal setae short. Sc short. R1 abruptly curved anteriorly near midlength. R2+3 absent. Legs without ornamentation or structural modification, except venter of hind femur ( Fig. 8 ) with few short setae posterobasally. Right side of epandrium greatly reduced ( Fig. 9 ), with venter of hypandrium occupying most of right side of terminalia; left side of epandrium much larger, occupying most of left side of terminalia (as in most other Metopina - group genera).

Taxonomic notes. Some features of Lenkoa phillipei are convergent on the structure of termitophilous Old World phorids in the subfamily Termitoxeniinae , especially the enlarged, white abdomen and the cylindrical, sparsely setose legs (Brown et al. 2015). The structure of the abdomen, however, with its distinctive gland openings, shows that this is a metopinine fly, as is also possibly indicated by the associated males.

Figures

FIGURE 6. Possible male of Lenkoa phillipei new species, lateral view.

FIGURES 1 – 3. Lenkoa phillipei new species, female. Figure 1. Lateral view. Figure 2. Head, anterior view. Figure 3. Thorax, lateral view. Abbreviations: anepm—anepimeron, cx 1 — forecoxa, kepst—katepisternum, mr—possible fused sclerite of meron + other sclerites, plr—posterolateral ridge, p spr—posterior spiracle, prepst—proepisternum.

FIGURES 4 – 5. Lenkoa species, dorsal view. Figure 4. Lenkoa phillipei new species. Figure 5. Lenkoa aurita Borgmeier (from Borgmeier, 1969).

FIGURES 7 – 10. Possible male of Lenkoa phillipei new species. Figure 7. Wing. Figure 8. Hind leg, posterior view. Figures 9 – 10. Male terminalia, right side, left side.