Yara oyaguei, Trujillo & Cañote

Trujillo, Gabriel A. & Cañote, Javier, 2019, First confirmed species record of Hydroscaphidae from Peru: description of a new species of Yara Reichardt and Hinton, and key to species (Coleoptera: Hydroscaphidae), Zootaxa 4638 (3), pp. 344-350 : 345-349

Yara oyaguei Trujillo & Cañote, new species

Holotype (♂): Peru: San Martin: Moyobamba : Soritor. 6° 8’23.87”S, 77° 4’8.69”O, 848 masl., 09.XII.2016. Leg G. Trujillo. Det. G. Trujillo, mounted on a card ( UNALM) ; Paratypes: 1 ♂, same information as holotype and mounted on a card ( CORBIDI), and 5 ♀ paratypes, distributed as follows: two specimens, same information as holotype and mounted on cards ( CORBIDI); three specimens, same information as holotype (except 10.VIII.2014) and mounted on slides ( UNALM). Two additional ♀ paratypes, same information as holotype (except 02.VI.2016) and mounted on cards, are deposited in Entomology Division , University of Kansas (Lawrence, KS, USA) . Additional specimens, and dismembered body parts, are distributed in 6 slides, all with same information as holotype (except 02.VI.2016), and deposited in CORBIDI

Description: Habitus. Body fusiform and elongated (length, 1.18–1.34 mm).

Coloration. Head frons brown with yellow borders near eyes. Pronotum yellow, with a pair of faint brown spots. Elytra yellow with a brown central spot covering 1/3 of the elytra, and with a thick dark brown border extending from the middle to the posterior part of the elytra but with a thicker border toward the center of the body ( Figs 1 –2 ). Sternum brown. Abdominal Segment IV dark brown, abdominal segments V–VII yellow. MALE: tergite VIII and IX yellow, with a dark brown spot over its central part extending over 1/3 of the tergite ( Fig. 1 ). FEMALE: tergite VIII yellow with a dark brown spot in the center extending over 1/3 of the tergite ( Fig. 2 ).

Head. Eyes not protruding off the head outline. Maxillary palp 4-segmented, maxillary palpomere IV retractable, third maxillary palp with a few setae along the lateral margin. Mentum and submentum not fused. Antennae 8-segmented, antennal scape approximately as long as the pedicel, antennomeres III and IV combined, short and very similar in size and shape to antennomeres III–VII, segment VIII elongated and as long as antennomeres III to VII altogether ( Fig. 3 )

Thorax. Elytra with moderately long setae covering its dorsal surface and lateral margins. Hind wings developed, bearing a marginal fringe. Metacoxae with a triangular projection extending to the trochanter ( Fig. 4 ). Ventral and dorsal part of the trochanter of the front, middle and hind legs with a few circular indentations near the base; Metatrochanter with a series of 4 spine-like setae along lateral margin ( Fig. 4A ). Foretibia with only a single long and rather blunt spine on its posterior, distal margin, mesotibiae and metatibiae with spines ending in sharp point ( Fig. 6 ).

Abdomen. Tergite IV nor covered by a dense patch of setae, instead with a few moderately elongated setae that are thickened at their base. Abdominal segments V–VII with elongated setae. MALE: posterior margin of sternite VIII asymmetric, with 3 differentiated setae that are curved and located on its left side ( Fig. 7 ). Tergite VIII with asymmetrical posterior part, with a brown spot in the middle ( Fig. 8 ). Sternite and tergite IX ending in a sharp point with moderately long setae, the sternite IX with a faint central spot that diffuses towards its posterior section ( Fig. 9 ), tergite IX has a well-marked dark brown spot on its center ( Fig. 10 ). FEMALE: Apex of sternite VIII emargin- ated, with a very slight spot near its center ( Fig. 11 ); tergite VIII with a more pronounced emargination compared to sternite VIII, with a dark brown spot in the center of the tergite ( Fig. 12 ). Abdominal segment IX absent or re- duced.

Genitalia. Aedeagus with a short, forked base that articulates almost from the front margin to a basal bulb of the long, filamentous median lobe ( Fig. 13 ). Female genitalia as in Fig. 14 .

Etymology. The new species is named after Eduardo Oyague, director of Division de Limnología of CORBIDI, who introduced us to the world of aquatic insects.

Discussion. The number of spine-like setae in the metatrochanter was found to be variable across examined specimens. In most specimens the number of spines was four, however some individuals presented three and five spines. While the number of metatrochanter spines is cited as fixed and thus a diagnostic feature for Yara maculata ( Short et al. 2010) and Yara marmontsedu ( Raudez et al. 2019) , this is not the case in Yara oyaguei . The apex of the sternite VIII and the tergite VIII of the female of Yara oyaguei resemble those of Yara dybasi and Yara marmontsedu , however Yara oyaguei has well-developed wings like Yara marmontsedu , unlike Y. dybasi . In addition, Reichardt and Hinton (1976) did not mention spots on the elytra of Yara dybasi , while Yara oyaguei has well-defined spots; the same are rather diffused in Yara marmontsedu .

Habitat. We found specimens studied in a shallow shore and run of a stream, with rock mixed with boulders and devoid of vegetation ( Fig. 15–16 ). Four males and 10 females were collected in June, August, and December, which coincides with the dry season. Sampling effort was considerable relative to the few individuals found. No specimen was observed alive and individual specimens were found scattered across their habitat. The distribution of Yara spp is shown in Figure 17 .

Figures

FIGURE 17. Map for species of Yara (black circle: Yara oyaguei, blue circle: Yara vanini, green circle: Yara maculata, yellow circle: Yara dybasi, red circle: Yara marmontsedu)

FIGURES 1–2. 1. Habitus of male, 2.Habitus of female

FIGURES 3–12. 3. Ventral view of head, 4. Hind leg with details of coxae and trochanter, 5. Middle leg, 6. Front leg, 7. Sternite VIII of male, 8. Tergite VIII of male, 9. Sternite IX of male, 10. Tergite IX of male, 11. Sternite VIII of female, 12. Tergite VIII of female

FIGURES 13–14. 13. Aedeagus, 14. Female genitalia

FIGURES 15–16. Habitat