Dianesia sheylae Álvarez, Núñez & Espeland, 2025

Dianesia sheylae Álvarez, Núñez & Espeland , sp. nov.

http://zoobank.org/ urn:lsid:zoobank.org:act:C7F75D96-5B35-498E-8689-98B00E369A4F

Figs. 2A–D View FIGURE 2 , 3G–I View FIGURE 3 , 6M–N View FIGURE 6 , 7M–O View FIGURE 7 , 8 View FIGURE 8 , 9I View FIGURE 9 , 10C View FIGURE 10

Diagnosis. Dianesia sheylae sp. nov. can be distinguished from all its congeners by the following combination of characters: uniform chestnut brown upper surface background color with orange glow reduced to base; FW postdiscal white band very well developed dorsally with the first four spots more marked, much more developed and marked ventrally; discal black band between discal cell and 2A outwardly angled; UNFW ocellus as large as the UNHW ocellus; male genitalia with broad valvae with short narrow tips and with prominent ventral uncus tooth-like protuberance; female genitalia with corpus bursae globose and short flat cylindrical signa with blunt tips. Barcode rDNC: 49(C), 55(T), 79(G).

Description. Eyes naked, green in life. Antennal socket orange; antennae slender, 36–38 alternate blackish and white antennomers, club blackish with white tip. Head, thorax and abdomen chestnut brown, the thorax with scattered dark orange pubescence and the abdomen with dark orange segment junctions. FW length: 13,6–14,2 mm ♂, 13,5–14 mm ♀. Male UPFW chestnut brown, darker from the postdiscal area towards outer margin, base dark orange with two dark brown concentric, discontinuous bands extending basally and discally, respectively, from the discal cell to 2A, the inner half of the basal band outwardly angled; a third incomplete band of the same color edging the discal cell, and a very small spot of the same color on the bifurcation of Cu 1 and Cu 2. A thin dark brown postdiscal line extending sinuously from costa to Cu 1 and then straight to the inner margin, internally edged by a blurred blackish area and externally edged by a white band consisting of six spots, the two between R 2 –R 3 and R 3 – M 1 thinner and well-defined, the two between M 1 –M 2 and M 2 –M 3 shorter and broader, and the two between M 3 –Cu 1 and Cu 1 –Cu 2 larger, broader and more diffuse. A developed submarginal curved broad orange band edged by diffuse blackish areas, interrupted by veins; an elliptical black ocellus on the anal angle, internally edged by the orange band. UPHW with similar pattern, but with basal dark orange color reduced, broader and more sinuous postdiscal brown line and submarginal orange band, the latter with more defined and broader black edging, no postdiscal white band, and a larger, square ocellus in the anal angle, internally edged by yellow and with an external metallic blue pupil. UNFW similar but paler with no orange color, basal half darker but whiter near inner angle and with the postdiscal white band much more defined and broader, extending towards inner angle; a light area near costa between the black bands of the discal cell; ocellus at anal angle larger and with an external superior small pupil of blue scales, internally edged by pale yellow scales. UNHW similar but paler with no orange color, basal half darker, basal and discal brown bands reduced, postdiscal brown band discontinuous, ocellus at anal angle with a greater cover of metallic blue scales. Genitalia with narrow, square-shaped tegumen; uncus weakly lobed, each lobe with a ventrally prominent tooth-like protuberance; gnathi slender, smoothly curved upwards near tip; vinculum anteriorly concave, slender but broader near aedeagus; valvae broad, simple, as long as the tegumen, tip short and narrow, sclerotized but membranous near attachment to vinculum, dorsally attached to aedeagus by a weakly sclerotized peduncle; saccus short, lightly rounded; aedeagus elongate and thin, continued in a long, membranous duct ( Fig. 6M–N View FIGURE 6 ).

Female similar to male but with elongated, narrower wings with rounder outer margins; a lighter dark brown background color on the UP, the basal orange more developed, extending beyond the postdiscal black line in the HW; and better developed postdiscal white band and marginal orange band, especially in the FW. Genitalia with ostium bursae compressed dorsoventrally, narrower towards the sclerotized antrum, lamella antevaginalis heavily sclerotized and spatulate, partially covering ostium bursae; lamella postvaginalis weakly sclerotized; ductus bursae narrow and membranous, punctate surface with several small, irregular folds; corpus bursae globose, flattened dorsoventrally, surface uniformly punctate, with numerous folds around junction with ductus bursae; two mid-lateral heavily sclerotized short flat cylindrical signa with blunt tips ( Fig. 7M–O View FIGURE 7 ).

Type material. Holotype — ♂ CUBA , Cienfuegos, Bahía de Jagua, Caletón de Don Bruno , 22º04’N, 80º27’W, 12/ VI /2024, col. Y. Álvarez & S. Yong, YAC (YAC-0601). Paratypes — 6♂, 6♀. Same data as for holotype, YAC (2♂, 2♀: YAC-0592, YAC-0593, YAC-0594, YAC-0600); same locality, 20/IX/2023, col. Y. Álvarez, DNA voucher Y183, YAC (1♂: YAC-0458); same locality, 4/IV/2024, col. Y. Álvarez & S. Yong, DNA vouchers DC-30, DC-36, DC-40, DC-41, ZUEC (1♂, 2♀: 14719, 14720, 14721), YAC (1♂: YAC-0512); same locality, 28/ VIII /2024, col. Y. Álvarez, YAC (1♂, 1♀: YAC-0644, YAC-0645); same locality, 20/III/2025, col. Y. Álvarez, YAC (1♀: YAC-0753).

Additional material. CUBA , Cienfuegos, Bahía de Jagua, Caletón de Don Bruno , 20/IX/2023, col. Y. Álvarez, four larvae in ethanol, DNA vouchers DCL 01A, DCL 01B, DCL 01C, DCL 01D, ZFMK (sex unknown).

Etymology. Named after Sheyla Yong, a renowned Cuban entomologist, and a dear friend to the first author, who played a crucial role in the development of this research and accompanied the first author in many fieldwork visits, particularly those conducted to study this species.

Distribution. Known only from Caletón de Don Bruno, in the western shores of Bahía de Jagua (“Bahía de Cienfuegos ”), Cienfuegos province, central Cuba ( Fig. 8 View FIGURE 8 ).

Habitat. Dry coastal forest ( Fig. 9I View FIGURE 9 ).

Biology. This insect is locally common at the few scattered vegetation patches where it has been located in the western entrance of the bay. It flies swiftly inside forest clearings and along trails, but sometimes within the thick vegetation. Males have preferential perching sites from where they chase passing insects, whilst females tend to fly closer to the host plants. Adults have been observed nectaring on Croton glabellus L., ( Euphorbiaceae ), Bourreria succulenta Jacq. and B. microphylla Griseb. (Boraginacaeae) . Adults are on the wing year-round, although they are more common from June to August, and fly from the early morning until late afternoon; we have seen an activity peak between 17 and 18 h. Adults from the dry season (November–April) can show a reduction of the orange color on the UP.

Immature stages. Final instar ( Fig. 10C View FIGURE 10 ): Head capsule orange, covered with numerous whitish setae. Prothoracic shield green yellow, covered by whitish setae and a pair of lateral black setae. Body dark green dorsally, yellow green laterally, these colors intergrading in the first five segments and delimited by a lateral diffuse white band from the sixth to the tenth segments, yellowish near anal plate; segment junctions whitish; white band running mid-dorsally along the body, broader and more marked in the final segments; two dorsolateral white bands, broader and more marked in the first three segments, externally accompanied by small whitish dots on the first three segments and by a white and a black longitudinal spots on the ninth segment; a lateral broad, round black spot edged with white on the fourth and fifth segments; each segment with a lateral white spiracle opening and a tuft of long whitish setae. Males with yellow-orange testicles visible dorsally in the seventh segment. Anal plate yellow, covered by numerous external long whitish setae.

Host plant. Buxus glomerata (Griseb.) Müll. Arg. ( Buxaceae ) ( Álvarez & Yong 2024).

Remarks. This insect was reported from the Cienfuegos Bay by Alayo & Hernández (1987) on the basis of specimens collected by Fernando de Zayas in June 1954, near Castillo de Jagua, to the south of Caletón de Don Bruno, where the original vegetation and the butterfly have now both vanished. The specimens collected by Zayas were not available for examination, and the butterfly remained undetected for 70 years after fruitless expeditions to the area, until its rediscovery in September 2023 ( Álvarez & Yong 2024). Currently only one population is known, occupying less than 2 km 2 of partially conserved dry coastal forest mixed with farms and houses. While it is likely present both to the west of the type locality and in the eastern side of the bay, where suitable, more conserved habitat patches prevail, several surveys had failed to locate it outside of the type locality. Not only is this butterfly very restricted in distribution, it is also the only Cuban member of the genus restricted to terrain outside any natural reserve on the island.