Deltaya Willmott, Nakahara & Espeland, 2023

Espeland, Marianne, Nakahara, Shinichi, Zacca, Thamara, Barbosa, Eduardo P., Huertas, Blanca, Marín, Mario A., Lamas, Gerardo, Benmesbah, Mohamed, Brévignon, Christian, Casagrande, Mirna M., Fåhraeus, Christer, Grishin, Nick, Kawahara, Akito Y., Mielke, Olaf H. H., Miller, Jacqueline Y., Nakamura, Ichiro, Navas, Vanessa, Patrusky, Brooke, Pyrcz, Tomasz W., Richards, Lindsay, Tan, Denise, Tyler, Stephanie, Viloria, Angel, Warren, Andrew D., Xiao, Lei, Freitas, André V. L. & Willmott, Keith R., 2023, Combining target enrichment and Sanger sequencing data to clarify the systematics of the diverse Neotropical butterfly subtribe Euptychiina (Nymphalidae, Satyrinae), Zoological Research 2023, pp. 1-73 : 38-67

publication ID	https://doi.org/ 10.1111/syen.12590
DOI	https://doi.org/10.5281/zenodo.7909517
persistent identifier	https://treatment.plazi.org/id/03EC879F-FFAA-FFB2-AB77-AA87FDD3116E
treatment provided by	Julia
scientific name	Deltaya Willmott, Nakahara & Espeland
status	gen. nov.

Treatment

Deltaya Willmott, Nakahara & Espeland , genus novum.

Type species — Papilio ocypete Fabricius, [1777] , by pre- sent designation.

Zoobank registration: https://zoobank.org/Nomenclatural Acts/C5441C63-9631-4E9D-A37F-6ED27676D185

Systematic placement and diagnosis. Deltaya gen.n. is a member of the ‘ Splendeuptychia clade’ ( Figure 10 View FIGURE 10 ), and three of its four ‘core’ described species, Deltaya ocypete comb.n, Deltaya louisammour comb.n and Deltaya opima comb.n. ( Figures 33 View FIGURE 33 and 34 View FIGURE 34 ), form a clade with low support (FULL dataset SH-aLRT = 67.9, UFB = 53). Deltaya pallema comb.n. is closely related to D. ocypete and is also considered a ‘core’ species ( Benmesbah et al., 2018). Two species are placed with some support as forming a grade sister to this clade (SHaLRT = 85.4, UFB = 83) and are included here within the genus ( Deltaya andrei comb.n. and Deltaya probata comb.n, see Discussion below). Within the ‘ Splendeuptychia clade’, Deltaya gen.n. is a member of the same clade as Modica gen.n., Paryphthimoides , Colombeia , Scriptor , and Malaveria , with it being placed as sister to Scriptor (SHaLRT = 98.3, UFB = 61), but none of the nodes connecting these genera have strong support. Deltaya gen.n. lacks obvious morphological synapomorphies, but the following are somewhat distinctive characters within Euptychiina (shared variously with other genera) on the ventral wings ( Figures 33 View FIGURE 33 and 34 View FIGURE 34 ): relatively broad dark transverse discal bands; the presence of only five relatively large postdiscal VHW ocelli, with each ocellus having two pupils, which are small dots (in cells Cu 2 -Cu 1, M 2 -M 1) or elongate and large (in cells Cu 1 -M 3, M 3 -M 2, M 1 -Rs), and the postdiscal ocelli on both wings lying within a broad darker band (umbra). Overall, the genus is best distinguished from phenotypically similar genera by the pale pupils of the HW ocellus in cell Cu 2 -Cu 1 not being visible on the dorsal surface, by the VHW postdiscal ocelli in cells Cu 1 -M 3 and M 3 -M 2 being of similar size, round (not elongate) and each containing two enlarged, elongated silver pupils (when the ocelli are large enough for the pupils to be visible), and by the marginal line widening in the VHW tornus. This last character also occurs in Scriptor , some Paryphthimoides , and some other Euptychiina (e.g. Vanima labe , Vanima palladia ), but is otherwise a relatively uncommon character. Characters that differ among the genera within the clade in which Deltaya gen.n. is placed are summarized in Table 1 View TABLE 1 .

The genitalia of both sexes are described below and there are no obvious synapomorphies for the genus as a whole. However, ‘core’ Deltaya gen.n. ( Figure 35 View FIGURE 35 ) share several distinctive characters, including: (a) the aedeagus has two relatively long and broad rectangular patches of cornuti (smaller or no patches in other species). (b) in the female, the anterior half of the 8th tergite is weakly sclerotized and the intersegmental membrane between the 7th and 8th segments is pleated and expandable; (c) the ventral portion of the intersegmental membrane between the 7th and 8th segments bears a sclerotized plate similar to the 7th sternite; (d) a sclerotized rectangular lamella antevaginalis extending horizontally and fused with the lateral plate of the 8th abdominal segment is present (as noted by Nakahara, Kleckner, et al., 2020).

Etymology. The generic name is derived from the name of the fourth letter of the Greek alphabet, delta, whose triangular upper-case symbol is the source of the word used in multiple languages to describe the broadening of a river at its mouth. The name is treated as a feminine noun in the nominative singular, and refers to the broadening VHW marginal line at the tornus that distinguishes Deltaya species from a number of other similar species.

Description ( Figures 33 – 35 View FIGURE 33 View FIGURE 34 View FIGURE 35 ). Some notable characters include: eyes setose; pterothoracic legs dorsally slightly darker, tibia with two principal longitudinal rows of spines ventrally, pair of spurs of similar length at distal end of tibia, first tarsomere with three principal longitudinal rows of spines ventrally, remaining tarsomeres with four principal longitudinal rows of spines ventrally. Medium-sized Euptychiina (FW length typically 19 – 25 mm), FW triangular and rather rounded at apex, HW rounded. No strong sexual dimorphism: Dorsal wings dark brown to blue-grey, pale pupils of ocellus in Cu 2 -Cu 1 not visible on DHW, no androconial scales present. Ventral wings blue-grey to brownish grey; relatively broad, dark brown to reddish brown discal and postdiscal lines traversing both wings; VFW with three postdiscal ocelli in cells Cu 1 -M 3, M 3 -M 2, M 2 -M 1, anterior ocellus more clearly marked than remainder, lying within a broad dark brown band (umbra); VHW similar to VFW but with five postdiscal ocelli between veins Cu 2 and Rs, those in Cu 2 -Cu 1 and M 2 -M 1 typically slightly larger, black-centred with two silver dots in each ocellus as pupils, ocelli in M 1 -Rs similar but much smaller, and those in Cu 1 -M 2 with dark brown centres and elongate silver pupils; marginal line thin and even throughout (except rather broad throughout in D. probata comb.n.), thickening noticeably at tornus. Male eighth abdominal tergite reduced dorsally, leaving a sclerotized strip along anterior edge and no or an isolated weakly sclerotized patch in posterior portion. Male genitalia with uncus longer than tegumen, brachia pointing slightly dorsally of uncus and about two-thirds its length; valvae elongate with dorsal edge straight or (‘core’ Deltaya gen.n.) with projection near distal tip covered with tiny spines; aedeagus lacking cornuti but with tiny spines scattered dorsally in D. probata comb.n. and D. andrei comb.n., and with cornuti in ‘core’ Deltaya gen.n. forming two relatively broad and long rectangular patches of tiny spines; intersegmental membrane between eighth segment and genitalic capsule in D. andrei comb.n. forms a ventro-lateral, eversible ‘pocket’ containing dense, long, black scales. Female genitalia has eighth tergite reduced to a posterior sclerotized patch about one- to two-thirds width of segment, eighth segment with large irregular lateral sclerotized plate extending broadening dorsally and with indentation at dorsal edge, antrum unsclerotized, ductus bursae unsclerotized, corpus bursae small, oval and with two narrow sub-parallel signa. ‘Core’ Deltaya gen. n. have additional characters described above under Diagnosis.

Distribution and natural history ( Figure 36 View FIGURE 36 ). Deltaya gen.n. contains six described species and probably several undescribed species, which occur in rainforest from sea level to 1400 m and are confined to South America east of the Andes. The genus reaches its peak diversity in the central and western Amazon, where both sexes are typically uncommon in the understory of both disturbed and undisturbed forest, except for D. ocypete comb.n., which may also be locally common in secondary habitats, including in the drier interandean valleys and extra-Amazonian regions from Bolivia across to south-eastern Brazil. Deltaya gen.n. species have also been recorded in fruit-baited traps ( Benmesbah et al., 2018; Oliveira et al., 2021; Zacca, Casagrande, et al., 2017). The immature stages have not been described for any species to date, and while there are records of Cyperaceae and Poaceae as hostplants of D. ocypete comb.n. ( Singer & Ehrich, 1993), these require confirmation given prior confusion over the identification of this species.

Discussion. Benmesbah et al. (2018) discussed in detail the taxonomic history of the type species of this genus, Papilio ocypete , and designated a specimen with a DNA barcode as the neotype. This species and three other described species, D. opima comb.n., D. louisammour comb.n. and D. pallema comb.n., form a clade based on DNA sequences (‘core’ Deltaya gen. n.), and share several morphological synapomorphies. All these species were previously placed in Magneuptychia by Lamas (2004), but, for the same reasons as discussed under Modica gen.n., they cannot reasonably be accommodated in any described genus, except perhaps Scriptor . Nevertheless, monophyly with Scriptor is only weakly supported in our results, and we thus believe that description of a new genus is the best solution. As mentioned above under Systematic Placement and Diagnosis, we also provisionally include two species in Deltaya that are weakly supported based on molecular data as members of the same clade as ‘core’ Deltaya gen.n., namely D. probata comb.n. ( Figure 34d View FIGURE 34 ) and D. andrei comb.n. ( Figure 34c View FIGURE 34 ). Although both species share some wing pattern and genitalic similarities with ‘core’ Deltaya gen. n., none of these are convincing synapomorphies for Deltaya gen.n. Deltaya andrei comb.n. has a very distinctive autapomorphy, namely a pocket of dense black scales adjacent to the valvae in the male genitalia, while the wing pattern of D. probata comb.n. is rather different from the remaining Deltaya species, with a VHW marginal line that is thickened throughout. Only COI sequences are available for D. probata comb.n., and COI + RPS5 for D. andrei comb.n., and more complete molecular data for both species and other members of the ‘ Splendeuptychia clade’ are therefore needed to confirm the generic classification of D. andrei and D. probata .