Pseudotinea Hall and Callaghan, 2003

HALL, JASON P. W. & CALLAGHAN, CURTIS J., 2003, A revision of the new riodinid butterfly genus Pseudotinea (Lepidoptera: Riodinidae), Journal of Natural History 37 (7), pp. 821-837 : 822-830

Pseudotinea Hall and Callaghan , gen. n.

(figures 1–13)

Type species Calydna volcanicus Callaghan and Salazar, 1997: 57–61 .

Etymology

The name is derived from the Greek ‘pseudo’, meaning ‘false’ or ‘similar to’, and the Latin ‘tinea’, meaning ‘moth’, in reference to the moth-like appearance of these riodinids.

Diagnosis

The members of Pseudotinea somewhat resemble certain species currently treated in the genera Adelotypa Warren and Petrocerus Callaghan and even certain moth species, such as those in the Neotropical family Hedylidae (argued by Scoble (1986) to belong in the Papilionoidea) (see Scoble, 1990, 1998). However, the characteristic elongate and scalloped wing shape of the genus Pseudotinea is not found elsewhere in the Riodinidae , although such pronounced scalloping alone is found in the unrelated monotypic riodinine genus Amphiselenis Staudinger. The combination of long labial palpi, a narrow and elongate abdomen and a mottled moth-like ventral surface is also diagnostic. The male genitalia are interspecifically rather homogeneous, but present a distinctive phenotype for the family. Male genital synapomorphies for the genus include the shape of the valvae and aedeagus, the latter having a very large posterior aperture and narrow, elongate, upwardly curved tip, and the presence of two distinctive aedeagal cornuti, a large and elongate, heavily sclerotized serrate right-hand one, and a rounded left-hand one covered in swirls of variably sized spines (see figures 7–10).

Description

Male

Fore wing length: 10.5– 18 mm.

Wing shape. Both wings somewhat elongate; fore wing costa straight, fore wing distal margin variably scalloped and produced into points at middle of cells Cu1 and M2, creating variably falcate apex. Hind wing distal margin variably scalloped and produced into points at middle of cells Cu1 and M2.

Venation (figure 6A). Four fore wing radial veins.

Dorsal surface. Ground colour of both wings shades of brown to black; a variably sized orange or white postdiscal patch typically present on fore wing, extending from vein 2A or Cu2 to vein M2; all species have three evenly spaced darker brown marks in discal cell of fore wing, one marking cell end, and two towards base of cell Cu2, faint column of disjointed postdiscal spots sometimes present; distal fringe brown with pale brown to white scaling in cells Cu2, M1 and M3 to R 4+5. Hind wing same as fore wing except orange postdiscal patch in same cell spaces only occasionally present; white scaling at distal fringe not present in apex.

Ventral surface. Fore wing ground colour brown mottled with paler brown and grey scaling; basal dark brown spots and postdiscal patch as on dorsal surface but latter paler if orange; small white flecks variably prominent along costal margin, apex or entire submargin paler brown, grey or dirty white, distal margin dark brown; submarginal black or dark brown spots variably prominent and sometimes only patchily discernible. Hind wing same as fore wing except dark brown square often visible above discal cell, postdiscal dark brown markings typically more extensive, often with pale grey scaling distally at anal margin extending variable distance to costa, dorsal postdiscal patch typically not visible.

Head. Labial palpi typically brown on dorsal surface and grey on ventral surface, second and third segments elongate (figure 6B); eyes brown and bare, cream or pale brown scaling at margins; frons brown typically with grey-brown at margins; antennal length approximately 60% of fore wing length, segments brown with prominent white scaling at base, narrow disjointed nudum line along ventral inner margin of shaft; clubs long and flat, dorsal surface brown, ventral surface brown or grey-brown.

Body. Dorsal surface of thorax and abdomen brown, ventral surface dirty dark grey; legs shades of brown; tarsus of fore leg unimerous, coxa relatively short (figure 6D); mid leg and hind leg with a tibial spur and a group of spines at inner distal tip of tibia and tarsal segments one to four, several further spines along inner distal margin of first tarsal segment (figure 6F).

Genitalia (figures 7–10). Uncus rectangular with rounded ventral posterior margin, separated from triangular tegumen by triangular lightly sclerotized lateral fenestration; vinculum ‘S’-shaped and slightly broader at middle, often folded over in upper two-thirds, produced into small saccus ventrally with triangular posterior section, incomplete dorsally (i.e. not present around anterior margin of tegumen); valvae with angular lower posterior corner, variably bulbous ventral margin and variably short projection from upper posterior corner, joined dorsally by soft tissue; aedeagus of approximately even width with ventral bulge towards tip, large dorsal opening posteriorly, ventral tip narrow and elongate, containing one elongate heavily sclerotized triangular structure at right with pointed or rounded teeth at tip and along left side (becomes dorsoventrally expanded and directed to right when vesica is everted), and one rounded lightly sclerotized structure at left covered with variably sized spines (becomes inflated with spines forming a left and anteriorly directed swirl when vesica is everted); pedicel broad and strap-like.

Female

Differs from male in following ways: fore wing length 12–14.5 mm (females not known for largest species).

Wing shape. Both wings more rounded and not as elongate; distal fore wing margin pronouncedly more scalloped in species where male does not have markedly scalloped distal margin.

Dorsal surface. Ground colour of both wings paler brown; orange postdiscal wing patches present in all known females even when absent in males, typically more extensive both distally and proximally, in one species ( eiselei ) extending to wing bases.

Ventral surface. Ground colour of both wings slightly paler.

Head. Second palpal segment more elongate (figure 6C).

Body. Fore leg with one or two small spines at inner distal tip of tarsal segments two and three, two long spines on segment four (figure 6E).

Genitalia (figures 11–13). Corpus bursae ovoid, signa small peg-like sclerotized invaginations with small aperture, ductus bursae and ductus seminalis, which joins former at entrance to ostium bursae, unsclerotized, ostium bursae broad and ‘U’-shaped with no sclerotization dorsally.

Systematic position

The taxa caprina, hemis and volcanicus were all described in the genus Calydna Doubleday (Hewitson, 1859; Schaus, 1927; Bridges, 1994; Callaghan and Salazar, 1997), and the first two of these were treated in the ‘Hiriiformes’ species-group (cohors) of Calydna by Stichel (1930). However, Calydna and its relatives are being revised by the first author, and the wing shape and pattern, and male genital characters outlined in the Diagnosis clearly distinguish the aforementioned group of species from the type species of Calydna (thersander Stoll) and its relatives, and all other genera, necessitating the description of a new genus, Pseudotinea , for them and two further species described below.

The wing pattern elements of Pseudotinea species are so heavily modified compared to the typical riodinid ground plan that such characters are useless in helping to identify close relatives. By virtue of possessing a pedicel connecting the aedeagus to the base of the valvae, Pseudotinea can be placed in the subfamily Riodininae (Harvey, 1987) . However, the genus does not possess any of the synapomorphies defining the nine currently recognized riodinine tribes (sensu Harvey, 1987, and Hall, 1998, 1999b) and thus we tentatively place it for now in the paraphyletic incertae sedis section (four fore wing radial veins) of Harvey (1987). The male (and in many cases female) genitalia of all genera and species groups in the aforementioned incertae sedis section have been examined. However, only those of Calydna punctata C. and R. Felder and C. chaseba Hewitson approximate those of Pseudotinea species , and then only to a limited degree in the arrangement of aedeagal cornuti. Morphologically, the members of Pseudotinea differ from those of all other genera in the incertae sedis section by possessing an incomplete vinculum dorsally at the anterior margin of the tegumen and long labial palpi, characters prevalent in many members of the Nymphidiini (e.g. see Stichel, 1910–11; Hall, 1999a, 1999b). While we conservatively place Pseudotinea in the incertae sedis section (4 FRV) of Harvey (1987), we suspect that it may eventually be found to belong in the Nymphidiini .

Biology

Pseudotinea species are known to occur across a wide range of elevations (600– 2100 m) and habitats, from the ecotone of lowland rainforest and lower premontane forest to open montane scrub. Available information suggests that Pseudotinea species are typically encountered in open areas such as clear hilltops and hillsides, and even in areas that have been disturbed by man, such as plantations. At present, two species are known from the Andes and three from the mountains of south-east Brazil. The often very restricted ranges of Pseudotinea species suggest that there are probably further undescribed species, and raise concerns about their conservation status. Given the great rarity of all species, which are collectively only represented by approximately 35 specimens in collections (mostly P. volcanicus ), their restricted ranges, and the devastatingly rapid rate of deforestation in their mid-elevation Andean and south-east Brazilian habitats (Myers, 1988; Brown, 1991; Brown and Brown, 1992; Dinerstein et al., 1995; Myers et al., 2000), most species should be considered ‘Vulnerable’ or even ‘Endangered’ under the Red Data Book categories of the International Union for the Conservation of Nature and Natural Resources ( IUCN) (e.g. see Collins and Morris, 1995). Two of the south-east Brazilian species have not been seen in the last 50 years.

Males have been encountered as solitary individuals or in small groups perching in the afternoon from 12.00 to 3.20 p.m. on top of the leaves of low bushes with their wings outspread. Their flight is slow with a rapid wing beat when not disturbed, but can become rapid when males are involved in aerial whirling. The more rarely encountered females have been found near these male perching areas, and visiting flowers. The slow flight and aposematic dorsal coloration of some species suggests that they may be involved in mimicry with day-flying moths, and, in the case of Pseudotinea eiselei , certain lycaenids (Benyamini, 1995). The north Andean species probably flies throughout most of the year, but the southern Andean and southeast Brazilian species have only been encountered during the southern summer months, from September to May.

Distribution

Pseudotinea species occur in the Andean regions of Colombia, Ecuador and Argentina, and the mountains of south-east Brazil (see figure 14), although the genus is very likely to range along the length of the east Andean slope, also occurring in Peru and Bolivia . The centre of diversity lies in south-east Brazil . While a few riodinid genera are endemic to either the Andes or south-east Brazil , no others are solely restricted to both these biogeographic regions. However, a few nymphalid genera (e.g. Cybdelis Boisduval ) do exhibit such a distribution, and Ebert (1960) was the first entomologist to discuss the biogeographical connection between the south-east Brazilian and Andean butterfly faunas, one that has also been shown to exist in several other groups of organisms, including birds (Sick, 1985) and plants (Smith, 1962). Smith (1962) hypothesized that the Andes of modern-day northern Argentina and the mountains of south-east Brazil (around 27°S) were floristically connected during Pleistocene glaciations, allowing a temporary flow of the fauna and flora from one region to the other. The evidence from plants and birds ( Smith , 1962; Sick, 1985) suggests that this flow was mainly from the Andes to south-east Brazil .

Since only a few specimens of each Pseudotinea species are known, our understanding of their geographic ranges is poor. No two species have thus far been collected sympatrically, but P. caprina and P. gagarini (described below) do have overlapping distributions.

Pseudotinea volcanicus (Callaghan and Salazar, 1997) comb. n. (figures 1A–D, 6A–F, 7A, B, 11)

Calydna volcanicus Callaghan and Salazar, 1997: 57–61 . Type locality: Cerro Aguacatal , Caldas, Colombia. Holotype W MUNB [examined].

Identification and taxonomy

Average FW length: male 12 mm, female 13 mm. The male of P. volcanicus is readily identified by its more weakly scalloped distal wing margins, pale browncream instead of bright white distal fringe elements, typically uniform brown dorsal surface and pale mottled brown ventral surface that lacks any prominent pale or dark transverse bands on the hind wing. Some specimens have faint postdiscal orange scaling on the fore wing, but in specimens from a locality in north-east Ecuador this is more prominent. The male genitalia have a slightly shorter, downwardly rounded upper projection to the valvae, and a slightly shorter right-hand aedeagal cornutus. Typical females are similar to those of P. hemis , but do not have orange extending to the costa on the fore wing nor a prominent whitish postdiscal band on the ventral hind wing. Females from a population in north-east Ecuador have more extensive fore wing orange than the figured individual and no hind wing orange. The female genitalia of the three species examined, volcanicus , eiselei and hemis , differ slightly in the shape of the signa and ostium bursae, but with so few specimens to examine it is not possible to conclude whether these differences represent intra-or interspecific variation.

Biology

Pseudotinea volcanicus has been encountered between 600 and 950 m in Ecuador, at the ecotone of lowland rainforest and lower premontane forest, and at 1300 m in Colombia, in premontane habitat. In Colombia, males were found perching on the upper leaf surface of low bushes with their wings outspread, in a deep canyon and along the trails of a shaded coffee plantation from 12.00 to 2.00 p.m.; females were encountered in the same areas visiting flowers (Callaghan and Salazar, 1997). In central Ecuador, solitary males were encountered in a large forest lightgap beside a stream that was under partial cultivation with various small fruit and coffee trees, between 1.40 and 3.20 p.m., flying 5–6 m above the ground with a slow flight but very rapid wing beat. In north Ecuador, males were encountered perching in small groups along the shaded forest edge of a prominent hilltop from 12.45 to 2.45 p.m., where they would incessantly ‘patrol’ up and down a short stretch of several metres. Their flight was typically slow and fluttering, but became rapid when they engaged with conspecific males in spiralling aerial chases. Solitary females were found flying slowly in the understorey and along the forest edge between 8.30 a.m. and 12.00 p.m.. Although the species was relatively abundant at the north Ecuadorian locality in the wet month of August, during an extended return visit in the drier month of March, no individuals were seen, suggesting the species may be seasonal.

Distribution

This species was recently simultaneously discovered on the eastern slope of the western cordillera in Colombia and at the base of the eastern Andes in Ecuador (see figure 14). It probably also occurs in the Andes of Peru.

Specimens examined

Colombia: Caldas, Cerro Aguacatal and Cerro Clavijo, nr Ríosucio (April, July) 7 W, 2 X MUNB (+distributed among CJC and collections of J. LeCrom, E. Schmidt- Mumm and the Museo de Historia Natural , Universidad de Caldas, Colombia) .

Ecuador: Sucumbíos, Cerro Lumbaquí Norte, above Lumbaquí ( August ) 6 W, 2 X JHKW; 1 W MECN ( Museo de Ciencias Naturales , Quito, Ecuador) ; Napo, Pimpilala, nr Tena ( August , September ) 2 W JHKW ; Pastaza, km 42 Puyo-Arajuno rd (September) 1 X DA.