Types: HOLOTYPE (male): PERU, Ancash: ruta Conococha – Ocros, Abra, 10°15′22″S,77°15′11″W, 4800 m, 11.vi.2019, J. Farfán and J. Cerdeña, [MUSM]; Paratypes (10 males and 4 females): 1 male and 1 female: same data as the holotype [MUSA]; 5 males and 2 females: Peru, Ancash, paso carretera Conococha–Ocros, 4800–4850 m a.s.l., 13.vi.2019, T. Pyrcz [CEP-UJ] (1 female prep. genit. 1751_18.07.2019/K. Florczyk; prep. mol. CEPUJ 20,190,713, prep. mol. CEPUJ 20,190,714); 4 males and 1 female: Ocros vers Huaraz km 27, 10°15′23″S,77°15′14″W, 4800 m, 11.vi.2019, P. Boyer leg., [PBF].

Diagnosis: The new species is closely similar in wing size and shape to species previously assigned to the genus Piercolias, in particular P. cf. forsteri (Fig. 1E–H) from Ticlio, Lima, Peru, and P. huanaco (Staudinger, 1894), although the FW of Phulia stoddardi n. sp. is more elongated with a more convex outer margin. Also, the color pattern is similar to that of P. cf. forsteri, from which it differs in being lighter, with less black on the FWD, and in particular, by the row of subapical black spots which is parallel to the outer margin, whereas in other species previously assigned to Piercolias that same row is sharply displaced basally in cell M3-Cu1. The HWV color is similar to Piercolias, almost patternless but even darker, with a strong greenish suffusion as in P. cf. forsteri, in contrast to the dashed pattern of other high-elevation Pierinae, such as Phulia sensu stricto (Fig. 2A–D) and Infraphulia (Fig. 2E–F). The wing pattern of the species placed until now in Pierphulia (Fig. 2G–H) is, in this respect, intermediate, as it shows darker postdiscal dots on a uniform ground color.

Adults. A Phulia stoddardi male holotype upperside; B idem, underside; C. Phulia stoddardi female paratype, upperside; D idem, underside; E Phulia (Piercolias) cf. forsteri male, upperside (Ticlio); F idem, underside; G. Phulia (Piercolias) cf. forsteri female upperside (Ticlio); H idem, underside

A Phulia nymphula nymphula male, upperside; B idem, underside; C Phulia nannophyes nannophyes male, upperside; D idem, underside; E Phulia (Infraphulia) madeleinea male, upperside; F. idem, underside; G. Phulia (Pierphulia) nysias male, upperside; H. idem, underside

Adults: A Phulia phantasma male holotype, dorsal (Cerro Amancaes); B idem, ventral; C P. phantasma female paratype, dorsal (Llacanora); D idem, ventral; E Phulia (Theochila) maenacte maenacte male (Sao Francisco de Paula), dorsal; F idem, ventral; G Phulia (Theochila) maenacte itatiayae male (Itatiaya), dorsal; H idem, ventral

Description: Adults: MALE (Fig. 1A–B): Head: eyes patchy chestnut and dark brown, naked; palpi 2.5 times the length of head, black, covered with milky white scales; antennae reaching 2/3 of costa, black covered intermittently with white scales, denser on ventral surface of spoon-shaped club. Forewing (length: 17–18 mm) elongated with a convex outer margin and a subacute apex, densely hairy in basal part; fringes long and white. Venation (Fig. 7) characterized by the common stem of forewing M2 and R3+4; R2 arising basally from the stem of R3, not from the same stem as in Piercolias, but similarly to Phulia and Pierphulia; hindwing M1 and M2 arising from the same stem, as in Phulia but contrary to Piercolias, Pierphulia, and Infraphulia. Hindwing oval, densely hairy in basal part; fringes long and white. FWD mostly snow white except for some black scales along costa, a black discal cell end patch, a row of subapical patches, parallel to outer margin, from costa to vein Cu1, and a row of marginal, roughly triangular patches from apex to vein Cu2, gradually smaller. HWD snow white, dusted with some black scales in basal and post-basal area. FWV predominantly snow white, dusted with cream yellow scales along costa, outer margin, apical and subapical area; a faint discal cell black patch; and a series of equally faint subapical patches in cells M1-M2 to M3-Cu1. HWV cream yellow liberally dusted with black scales, denser in basal and post-basal areas, with a series of faint postdiscal black dots, one in every cell. Male genitalia (Fig. 4): similar to other congeners. Uncus short, similar to species formerly placed in Phulia, considerably shorter than tegumen, slightly incised basally; tegumen smooth and thin, uncus short, similar to former Phulia, valva massive with a sharp distal tip, as in former Piercolias, aedeagus short and tubular with a serrate ventral surface and a prominent basal bulbous projection. FEMALE (Fig. 1C–D): sexual dimorphism is slight, the female is somewhat smaller (FW length 15–17 mm), with more prominent black pattern and on the upperside the ground color is richer, milky white. Female genitalia (Fig. 5): Papillae weakly sclerotized and setose; prominent posterior apophyses, genital plates, consisting of large, lateral pockets, inwardly densely setulose, long and scarcely sclerotized ductus bursae except for the initial part, with a prominent accessory pouch, a large corpus bursae with large, double star-like signa at the entrance of ductus and a rudimentary secondary bursa, similar to the species placed previously in Piercolias.

Male genitalia of Phulia stoddardi n. sp.: A lateral view; B vertical view; C aedeagus lateral view; D aedeagus vertical view

Female genitalia of Phulia stoddardi n. sp.: lateral view

Etymology. This species is dedicated to Terry Stoddard, an amateur lepidopterist from the U.S.A., and co-author of many significant contributions to the knowledge of Nearctic butterflies, in recognition of his excellent collaboration over the years and for sharing his experience on high-elevation butterflies.

This species has been found so far only at the type locality at the highest part of the road from Conococha to Ocros, at 4800–4950 m a.s.l., on the northern side of the slopes (Fig. 13). Individuals were observed on a dry hillside almost devoid of any vegetation (Fig. 11A–B), except for some sparse “cushion” plants. Two species of Senecio (Asteraceae) were seen, one higher up on the mountain ridge, the other, lower, closer to a bog. Among cushion plants, three species of Asteraceae, Werneria sp., Baccharis sp., and Chaetanthera spp., were identified, as well as Gentiana sedifolia (Gentianaceae) (Fig. 11D–H). No Brassicaceae, a likely hostplant, were observed although, admittedly, due to time constraints, our search was not exhaustive. Individuals of Phulia stoddardi n. sp. remained inactive for most of the morning, until around 11 am when gusty winds stopped blowing. They were observed performing short patrolling flights, very low to the ground, and engaging in energetic interactions with passing individuals. After such interactions, they dropped to the ground and sought shelter or basked on stones with their wings wide open, touching the substrate, in a similar way as with other high-elevation Pierinae. Lateral basking, a posture common among Colias Fabricius, 1807, was not observed. When the temperature decreased, P. stoddardi n. sp. adults were observed seeking shelter by crawling under the rocks, presumably to avoid both freezing and desiccation. Adults were occasionally seen feeding on flowers, although at rest they were more frequently observed sitting on dry, sandy, and rocky slopes. Other species of butterflies seen in the area were exclusively pierids, including occasional passing Colias euxanthe C. Felder & R. Felder, 1865 and some Phulia garleppi Field & Herrera, 1977 (Fig. 11C), with the latter much more common around a bog situated approximately 150 m a.s.l. below the habitat of P. stoddardi n. sp.

[Hypsochila n. sp. Lamas (Lamas, 2004: 115, no. 315)]

Types: HOLOTYPE (male): PERU, Ancash, Cerro Amancaes, cerca Santo Toribio, [08°50′S,77°54′W], 3000 m a.s.l., 22.v.[19]80, G. Lamas, MUSM-ENT-006767, [MUSM]; PARATYPES (37 ♂ and 1 ♀): Ancash: 2 males: same data as holotype, MUSM-ENT-006759, 6763, [MUSM]; 2 males: [Cerro] Amancaes, N de Huaylas, [8°50′S,77°54′W], 2900 m a.s.l., 6.v.[19]79, V. Pacheco, MUSM-ENT-006762, 6768, [MUSM]; 1 male: same data, but 3000 m, 8.v.[19]79, MUSM-ENT-006758, [MUSM]; 1 male: Oriente de la Cordillera Negra, C[omunidad] C[ampesina] Shecta, 9°28′06″S,77°35′43″W, 4131 m, 05.ii.2012, B. Medina, [MUSM]; 6 males: road from Bamba, T. Pyrcz [CEP-UJ]; 1 male: same data [PBF]; 4 males: same data, J. Cerdeña & J. Farfan leg., [MUSA]; Cajamarca: 1 male: Cascas-Contumazá p[oste] k[ilometrique] 100, [7°24′35″S,78°48′4″W], 2750 m, 23.iii.2022, P. Boyer, [PBF]; 1 male: Cascas-Contumazá “borne kilometrique” 100, [7°24′66″S,78°48′076″W], 2650–2750 m, 19.vi.2018, [PBF]; 1 male: same data, [MUSA]; 6 males: Chilasque, 06°01′S,79°12′W, 1200 m, 13.vi.2000, G. Lamas, MUSM-ENT-006760, 6761, 6764, 6765, 6770, 6771, [MUSM]; 1 male: same data, except 12.vi.2000, R.K. Robbins, MUSM-ENT-006769, [MUSM]; 1 female: Llacanora, [7°11′S,78°25′W], 2720 m, 19.xii.2006, [R. Vila], [MUSM]; 1 male: Limón-Santa Rosa, 1800–3000 m, i-ii.1998, R. Marx, FLMNH-MGCL-147145, [FLMNH]; 1 male: same data, FLMNH-MGCL-147146, [FLMNH]; 1 male: same data, FLMNH-MGCL-147147, [FLMNH]; 1 male: same data, FLMNH-MGCL-147148; [FLMNH]; 1 male: same data, FLMNH-MGCL-147149; [FLMNH];1 male: same data, FLMNH-MGCL-147150, [FLMNH]; 1 male: vía Celendín-Balsas, El Choloque, [6°51′57″S,78°4′35″W], 1800–2000 m a.s.l., local collectors, vi-vii.2006, [MABO]; Amazonas: 1 male: Chachapoyas, [06°10′S,77°38′W], [2343 m], 1889, M. de Mathan, Ex Oberthür Coll. Brit. Mus. 1927–3., MUSM-ENT-006766, [MUSM]; 1 male: Molinopampa—Granada, [06°23′S,77°26′W, 2800–3000 m a.s.l.], B. Calderón leg., [CEP-UJ]; ECUADOR: Azuay: 1 male: Oña, [03°28′27″S,79°9′32″W], 2200 m a.s.l., 22.iii.[19]65, L.E. Peña, [MUSM].

Diagnosis: Phulia phantasma n. sp. can be recognized from species of similar size previously placed in Hypsochila, Tatochila, or Theochila by its more compact appearance resulting from its less elongate wings, being similar in this respect to some species of Hesperocharis C. Felder, 1862, such as H. marchalii (Guérin-Méneville, [1844]), which is actually syntopic with P. phantasma n. sp. These two species of similar size and flight pattern can be easily confused in the field. Particularly pale individuals of P. phantasma with reduced black in the DFW apex and reduced (or almost absent) dark VHW markings are very similar to some individuals of P. maenacte from southeastern Brazil, but can be readily distinguished (apart from distribution) by having the base of vein R4+5 on the FW much closer to the distal margin than it is to the base of vein M1, whereas in P. maenacte it is approximately equidistant. Otherwise, P. phantasma n. sp. can be distinguished from P. maenacte by the dark scaling that lines the VHW veins broadening and fusing towards the distal margin, rather than tapering or remaining similar in width, and by the presence of a line of dark postdiscal spots in cells M1-Rs to CuA2-2A on the HWV, which may be shaped like distally pointing arrows, or just present as diffuse dark scaling, always absent in P. maenacte but similar to species previously placed in Hypsochila or several species of Tatochila. From the majority of other species of Phulia, P. phantasma n. sp. may be distinguished by the lack of any dark scaling at the end of the FW discal cell, with the dark markings in the distal half of the FW present as a simple black triangular patch which variably fills the apex and may be almost absent. Other superficially similar species (such as those formerly placed in Hypsochila, e.g., P. microdice or P. huemul (Peña, 1964)), have at least the FW discocellular veins lined with black, and a variable line of black FW postdiscal spots.

Description: MALE (Fig. 3A–B): Head: eyes brown, bare, with narrow fringe of white scales at base and a yellow dorso-lateral spot; antennal shaft mixed black and white dorsally (24 antennomeres) with conspicuous rounded club (8 antennomeres) which is pale yellow except for proximal dorsal half which is black; labial palpi white with sparse long, black hair-like scales; top of head and frons white. Thorax: dorsal surface with black scales and long white hair-like scales from sides and near wing bases, ventral surface white, legs with sparse white scaling except for femur with denser white scaling and long white hair-like scales, mid- and hindlegs lacking tibial spurs (present in P. maenacte; Field 1958). Wings: Forewing (length 27–28 mm, n = 5) triangular, hindwing an elongate oval with slightly straighter margin in middle of wing and angled tornus; FW with four radial veins, R4 and R5 fused, with veins R4+5 and R3 originating relatively close to the apex (R4+5 approximately half length of R3+4+5), M2 originating independently of base of M1 + R3+4+5. FWD ground color white, variably present scattered blackish scaling filling apex with uneven basal edge indented in middle of each cell, scattered blackish scaling at very base of wing. HWD similar to forewing except lacking black apical scaling. FWV similar to dorsal surface except lacking dark scaling at wing base and dark apical scaling slightly paler, tinged yellowish, with very indistinct paler yellowish scaling forming intervenal stripes within darker apical area, costa with scattered pale grayish scales. HWV ground color pale yellow, slightly darker orange-yellow anterior of discal cell and more prominently along edge of costa, dark orange-yellow spot at base cell 2A-Cu2; scattered dark grayish scaling lining edges of veins and a forming a “Y”-shaped marking in middle of discal cell, line of indistinct dark gray postdiscal markings in cells 2A-Cu2 to Rs varying from distally pointing arrow shapes to indistinct spots, grayish scaling lining veins broadening and fusing towards margin. Abdomen: dorsal surface black, ventral surface white. Genitalia (Fig. 6): similar in overall form to other members of the genus, for example Phulia wagenknechti (type species of Hypsochila) as figured by Field (1958), notable features include long uncus (similar in length to tegumen), valvae with a blunt distal point, aedeagus of even width, and opening ventrally. In comparison with P. maenacte, there are several differences in the male genitalia, including in P. phantasma n. sp. a much longer uncus, greatly reduced in P. maenacte, and a tapering, downward-pointing aedeagus (flaring and upward-pointing in P. maenacte). FEMALE (Fig. 3C–D): similar to male, except as follows: forewing (length 25 mm, n = 1) and hindwing more rounded, ground color slightly yellowish, dark DFW apical marking more extensive and with intruding pale scaling middle of each cell; ventrally similar to heavily patterned males, FW with trace of indistinct yellowish lines in middle of each cell in apical half, HW with stronger yellowish tinge to pale areas. Genitalia not examined.

Male genitalia of Phulia phantasma n. sp.: A lateral view; B vertical view; C aedeagus lateral view; D aedeagus vertical view

Venation pattern of Phulia. A Phulia stoddardi n. sp.: B Phulia (Piercolias) huanaco; C. Phulia (Pierphulia) nysias; D Phulia nymphula; E Phulia garleppi; F Phulia (Infraphulia) madeleinea (B-F redrawn from Field, 1958)

Etymology: The name is a neuter Latin noun in the nominative singular meaning a ghost or phantom, in reference to the pale markings of this species and its mysterious rarity in collections.

Bionomics and distribution: This species is known from a large area of the central tropical Andes, extending from southern Ecuador to central Peru (Fig. 13). It is rare in collections which does not reflect its status in the field. The perceived rarity results from this species occurring in the areas which are seldom visited by lepidopterists, dry Andean valleys, and especially being confused with common white pierids, especially with Hesperocharis marchalii and Leptophobia aripa (Boisduval, 1836). Additionally, P. phantasma n. sp. is a very active, patrolling butterfly, only sporadically seen visiting flowers, such as of yellow and purple Onoseris albicans (Asteraceae) flowers (Fig. 12E), and not seeking humid areas where mud-puddling other pierids are frequently found. The flight is fast and swift. Although it has been recorded from a wide altitudinal range from 1200 to 4131 m, it seems that its optimal elevational range is between 2000 and 2800 m a.s.l. All individuals were collected between December and July, representing the wet season and first half of the dry season.

Our study provides strong support for the monophyly of the expanded concept (Zhang et al. 2021) of Phulia in both the COI (bs: 94) (Fig. 8) and the concatenated 3-genes tree (bs: 100) (Fig. 9). The internal topology of this large clade differs, however, between analyses based on only COI or on all three genes.

COI ML tree of Phulia, bootstrap values above 60 indicated at nodes. All the generic names used previously are shown in order to underline their relative position in the phylogeny. The genera Ascia and Ganyra are used as outgroups

Concatenated (COI, GAPDH, RpS-5) ML tree of Phulia, bootstrap values above 60 on the nodes. All the generic names used before are shown in order to underline their relative position in the phylogeny. The genera Ascia and Ganyra are used as outgroups

In the COI tree, former Phulia cluster with former Piercolias, Pierphulia, and Infraphulia, as well as with former Hypsochila and three species formerly placed in Tatochila, P. orthodice (Weymer & Maassen 1890), P. mercedis, and P. theodice, and forms a sister clade to P. autodice. Phulia xanthodice (Lucas 1852) and Phulia sp., in turn, form a sister clade to former Phulia and other species plus P. autodice, whereas P. homoeodice is situated on a long external branch relative to all previously mentioned species. Finally, Phulia maenacte and Phulia phantasma cluster together and are sister to all the other taxa. However, the COI tree is not fully resolved because the support values on deeper nodes are low. On the other hand, the support of terminal branches is high but they refer only to single, or exceptionally two species, simply meaning that the species identification based on external morphology fully agrees with barcode data.

In the concatenated tree, the former genera Phulia, Pierphulia, Piercolias, and Infraphulia cluster together in a weakly supported clade (bs: 41), sister to Phulia mercedis + Phulia wagenknechti, but branch support is low (bs: 48). Phulia orthodice is situated in an external position relative to all the abovementioned taxa, on a long branch, but again the common node support is low (bs: 36). Finally, Phulia maenacte and Phulia phantasma n. sp. form a weakly supported clade sister to all the other taxa. As in the COI tree, all the small internal clades composed of one or two species are strongly supported. In the concatenated tree, only a few species of former Tatochila + Hypsochila were included, which hampers understanding of the relationships of species formerly included in these genera in relation to other Pierina, and in particular the species of the Phulia sensu stricto clade. The only interesting noticeable difference is the position of Phulia orthodice as sister to the Phulia s. s. clade on the concatenated tree, and well-rooted in the Phulia sensu stricto clade in the COI tree. Otherwise, the topology of both trees is roughly similar, in particular the sister status of the Phulia phantasma n. sp. + Phulia maenacte clade in relation to the remaining genera.

Our results infer a divergence of the Phulia sensu lato clade from Ganyra josephina in the middle Miocene (Tortonian), ~ 8.8 Mya (4.97–11.8 HPD 95%) (Fig. 10), followed by the subsequent divergence of the two main clades of the Phulia group in the late Pliocene (Piacenzian), ~ 3.3 Mya (2.4–4.2 HPD 95%). The radiation of Phulia sensu lato occurred throughout the Pleistocene, with the divergence of P. maenacte and P. phantasma n. sp. at ~ 2.5 Mya (1.72–3.03 HPD 95%), and that of other clades of Phulia sensu lato slightly later, at ~ 2.1 Mya (1.55–2.51 HPD 95%). The two clades which form the Phulia sensu stricto group originated at ~ 1.8 Mya (1.34–2.07 HPD 95%). In addition, Phulia garleppi diverged from the rest of Phulia sensu lato at ~ 1.9 Mya (1.46–2.18 HPD 95%). The clades (Phulia stoddardi n. sp. + Phulia (“Pierphulia”) sp.) + two species previously associated with Piercolias (P. cf. forsteri + P. coropunae)) diverged at ~ 1.6 Mya (0.52–1.88 HPD 95%). The group comprising two species previously associated with Pierphulia (P. rosea + P. nysias (Weymer & Maassen, 1890)) + Phulia nymphula) separated at ~ 1.4 Mya (0.39–1.62 HPD 95%). The group comprising the species previously placed in Infraphulia (P. ilyodes) + Phulia sensu stricto (P. nannophyes Dyar, 1913 + P. paranympha Staudinger, 1894)) at ~ 1.2 Mya (0.36–1.51 HPD 95%), and the clades ((P. rosea + P. nysias) + P. nymphula) + (P. ilyodes + (P. nannophyes + P. paranympha)) diverged at ~ 1.5 Mya (1.1–1.83 HPD 95%) (Fig. 10).

A hypothesis of divergence timing of the genus Phulia (generic names used previously in parenthesis)

Habitat of Phulia stoddardi n. sp. in type locality: A Phulia stoddardi n. sp. male in the field, thermoregulating on rocky substrate; B sandy slope with lose boulders where most observations of adults took place, 4850–4900 m; C view on the lake and boggy area at 4700 m, biotope of Phulia garleppi were abundant; D view of the Cordillera Huaywash; E Werneria sp., and Asteraceae sp.; F Asteraceae sp.; G Senecio sp.; H Gentiana sedifolia (photos: P. Boyer)

Habitat of Phulia phantasma n. sp.: A. A cliff above the Contumazá – Cascas road B. Asteraceae plants along the road; C view on the valley of Cascas; D xerophytic vegetation along the Contumazá–Cascas road, 2700 m; E flowers of Onoseris albicans (Asteraceae) frequently visited by numerous species of pierids, including P. phantasma n. sp.; F patches of cloud forest below the Contumazá–Cascas road, 2700 m (photos: P. Boyer)

Distribution of Phulia phantasma n. sp. and Phulia stoddardi n. sp