Neoarisemus nyahururuensis, Ježek, Jan & Oboňa, Jozef, 2016

Ježek, Jan & Oboňa, Jozef, 2016, escriptions of two new species of Afrotropical Psychodidae (Diptera), Zootaxa 4144 (4), pp. 515-528 : 516-520

Neoarisemus nyahururuensis sp. nov.

( Figs 1–18 )

Type material. Holotype ♂: Kenya: Laikipia County, Nyahururu, Thomson's Falls: waterfall on the Ewaso Ng'iro river , 2 360 m a.s.l., 0° 2' 38.58" S, 36° 22' 13.49" E, stones under the waterfall, 13.ii.2015. Slide with a dissected specimen, Cat. No. 34686, Inv. No. 21997 ( NMPC) . Paratypes 12 ♂ (slides, NMPC): The same locality, date and collector, Cat. No. 34687–34698, Inv. No. 21998–22009. All material J. Oboňa leg. (by hand).

Etymology. Named after the type locality—Nyahururu.

Bionomics. Unknown. Adults were collected under the waterfall on wet vegetation or the slime film covering stones.

Distribution. Currently recorded only from Kenya.

Description. Male. Head broadly rounded with swollen kidney or C-shaped compound eyes laterally, folded posteriorly ( Figs 1, 3 ). Vertex a little elevated, with doubled protuberances terminally, separated by a cleft ( Fig. 1 ). Posterolateral margins of eyes with 6–7 alveoli of supraocular bristles on both sides. Eyes separated, eye bridge divided by sixteen facet diameters ( Figs 1, 2 ) and formed by 4–5 facet rows ( Fig. 2 ). Ratio of distance of apices of eyes (tangential points) to minimum width of frons approximately 1.2:1. Dorsal 1/3 of the eye section three times as narrow as ventral 2/3. Frontal suture vestigial, limited to prolonged horizontal rods on both sides and two sclerotized patches in the middle ( Fig. 2 ). Head setose in anterior as well as posterior parts ( Figs 1, 3 ). Scar patch above the upper apices of eyes is divided, slightly convex near vertical axis. The frontoclypeus has two vertical quite separated alveoli patches expanded laterally to the basis of antennae. Antennae ( Figs 4, 5 ) of 16 articles. Scape almost cylindrical, twice as long as pedicel which is globular; scales lancet-shaped, a little longer than pedicel diameter. Basal flagellomeres spindle-shaped, medial ones approximately pitcher-shaped with nodes bulbose, slightly asymmetrical and reduced internodes (necks). Antennomeres 13–15 fused, swollen basally, terminal antennomere globular. Last four antennomeres very dark in contrast to the preceding ones. Ascoids paired, palmate, with five branches. Mouthparts extending slightly beyond basal palp segment. For the labellum, as shown in Fig. 1 , the convergent lines of spines between both lobes are visible. Labellum bulbose, without digital protuberances in between ( Fig. 10 ). Length ratio of maxillary palps 1.0:2.1:2.1: 2.7, segment 4 not annulate ( Fig. 9 ). Ratio of maximum length of cibarium to length of epipharynx 2.3:1 ( Figs 1 , 11 ), labrum setose.

Thorax. Anepisternum with crescent shaped setose patch, mesothoracic allurement protuberance almost hemispherical ( Fig. 12 ), with a circular thoracic spiracle anteriorly. Wings ( Fig. 13 ) broadly lanceolate, 2.8 mm long—holotype, paratypes 2.5–2.8 mm, pointed distally in the ending of R5, somewhat expanded at the posterior margin. Wing membrane slightly infuscated except some basal dark areas. A large spot between C and R1, interrupted proximally, overlaps slightly R1 along whole its length, conspicuously expanded to R2+3+4 and the origin of R1. Additionally one dark spot et the origin of R5 and a second one reaching from the whole length of CuA1 to the rest of the distal part of the posterior wing margin. Sc connected with the basis of R1. Following veins or their parts strengthened: Sc only in the origin, inconspicuously; R1 nearly entire, conspicuously; R2 and R3 distally, R2+3+ 4 in distal half, whole R5, M1+2 basally, M3 distally, CuA1 for entire length, conspicuously, in contrast to slender CuA2 with a thicker hockey-stick-shaped start basally. Radial and medial forks complete, far before the ending of CuA2. Wing indices AB:AC:AD = 6.1:5.4:3.9; BC:CD:BD = 1.0:3.0:3.9. Wing index 2.0, medial wing angle 165° (BCD). Halteres ( Fig. 6 ) almost globular with a prolonged stem, lance-shaped scales and a line of fine hairs. Ratio of maximum length of halteres to their maximum width approximately 2.5:1. Ratios of lengths of femora, tibiae and first tarsal segments: P1 1.7:1.5:1.0, P2 1.8:1.8:1.1, P3 1.8:2.3:1.3. Paired tarsal claws of P1 haired basally as in Fig. 7 , twice pointed and bent distad. Tibiae of P1, P2 and P3 conspicuously attenuated basally.

Male genitalia with ejaculatory apodeme cane-shaped, sheltered between gonocoxites, not expanded laterally at basis, proximally circular (bag-shaped), with paired petal-shaped sclerites inside ( Figs 15, 18 ). Aedeagal complex conical and approximately pintle or thumb-shaped, hooked terminally ( Figs 15, 16, 18 ), with a spineshaped lateral element protruding in the middle, shorter than gonostyle. Gonocoxites elongate ( Figs 15, 17, 18 ), almost cylindrical, basally with gonocoxal apodemes, touched in midline, inner pair only tongue-shaped, separated in vertical axis of genitalia. Ratio of maximum length of gonocoxite (including basal lobuli) and aedeagal complex 1:1.1. Gonocoxites 1.9 times as long as pear-shaped gonostyli with four bristles terminally, of which two are minute. Epandrium oblong-shaped, bare ( Figs 14 , 18 ), central aperture prolonged, savoy biscuit-shaped, ventral plate not observed. Hypandrium stripe-shaped ( Figs 15, 18 ). Hypoproct collar-shaped, with two deep narrow clefts distally on both sides and central tongue-shaped projection, annulated in the middle and haired terminally ( Figs 8 , 14 , 18 ). Epiproct fold-shaped, haired. Epandrial clasping lobes with enlarged bases and slender, strongly arched blade, slightly enlarged in distal half, three times as long as epandrium, with three brush-like tenacula ( Figs 14 , 18 ).

Female. Unknown.

Differential diagnosis. N. nyahururuensis sp. nov. is morphologically similar to N. collarti ( Satchell, 1955) , however, wing index is only 1.97 ( Fig. 13 ), the base of R2+3+4 shows a refracted angle ( Fig. 13 ) and the ending of CuA2 is placed distally to wing forks ( Fig. 13 ). Remnants of an interocular suture and frontal medial elements are developed ( Fig. 2 ). Gonostyli with four bristles from which two are minute ( Figs 15, 17 ) and aedeagal complex is stick-shaped ( Figs 15, 18 ). On the other hand collarti has wing index 3.20, the base of R2+3+4 has not got a refracted angle, both wing forks are in one line with the ending of CuA2. Remnants of an interocular suture and frontal medial elements are not developed. Gonostyli with only two bristles terminally and aedeagal complex is widened in the middle (compared only with the original figure of collarti , as in the holotype slide the genitalia is preserved in dorsolateral view–Kvifte, pers com).

Figures

FIGURES 1 – 8. Neoarisemus nyahururuensis Ježek & Oboňa sp. nov. male. 1. Head, frontal view. 2. Frons and facets in detail, frontal view. 3. Fold of eye, caudal view. 4. Basal antennomeres. 5. Apical flagellomeres. 6. Haltere, lateral view. 7. Tarsal claw of P 1, lateral view. 8. Hypoproct, caudal view. [Scale: 1 – 4, 6 = 0.2 mm; 5, 8 = 0.1 mm; 7 = 0.05 mm]

FIGURES 9 – 14. Neoarisemus nyahururuensis Ježek & Oboňa sp. nov. male. 9. Maxilla and palpus maxillaris. 10. Terminal lobes of labium. 11. Pharynx, cibarium, labrum and epipharynx, dorsal view. 12. Thoracic sclerites, lateral view. 13. Wing. 14. Epandrium and clasping lobes, dorsal view. [Scale: 13 = 1 mm; 12 = 0.5 mm; 9, 11, 14 = 0.2 mm; 10 = 0.1 mm]

FIGURES 15 – 18. Neoarisemus nyahururuensis Ježek & Oboňa sp. nov. male. 15. Aedeagal complex and gonopods, dorsal view. 16. Apex of aedeagal complex, lateral view. 17. Gonocoxite and gonostyle, lateral view. 18. Aedeagal complex, gonopod, epandrium and surstylus, lateral view. [Scale: 15, 17 – 18 = 0.2 mm; 16 = 0.1 mm]