INTRODUCTION

The Neotropical Region, while vast and with a hugely diverse biota, is comparatively unexplored with respect to collection and study of Elachistidae. It had been tacitly assumed that the Elachistidae had little or no representation in the humid tropics. The first species recorded from the tropics of the region, Elachista albisquamella, was described by Zeller (1877) from Colombian material. Much later, one further species was reported from Ecuador (Perittia smaragdophanes) by Meyrick (1932) and one (Elachista saccharella) from Cuba by Busck (1934). During the last seven to eight decades there have been practically no investigations of tropical Elachistidae of the New World. Recent efforts to collect South American Microlepidoptera have yielded additional specimens of Elachistidae, including two species from Bolivia and Peru: Perittia punatensis and Elachista vasrana (Kaila, 2000) (Fig. 1).

Fig. 1

Distribution map of Elachistidae species recorded from the tropical America: 1, Elachista albisquamella Zeller (1877); 2, Perittia smaragdophanes (Meyrick, 1932); 3, Elachista saccharella (Busck, 1934); 4, Perittia punatensis Kaila, 2000; 5, Elachista vasrana Kaila, 2000; 6, Stephensia armata Sruoga, new species.

Note: a taxonomic position of Elachista tersectella described from Bogota, Colombia by Zeller, 1877 and Atmozostis hilda from Cali, Colombia by Meyrick, 1932 has not been proven yet (Kaila, 2000), therefore, the species are not mapped.

The Belize collecting trip, undertaken in April 1998 by the second author with the assistance of Simon Hill (University of Westminster, UK), has resulted in the discovery of a remarkable new species – Stephensia armata sp. n.

MATERIALS AND METHODS

Material studied was collected during Microlepidoptera collecting trip by the second author, accompanied by S. R. Hill (University of Westminster, UK) in Belize, Las Cuevas Research Station (April 1998). Adult moths were obtained by attracting them to mercury-vapour light from a lamp suspended slightly above eye-level and 5–10 cm in front of a white screen, rather closer than is usual in the standard method for light-collecting (described by Robinson et al., 1994) in which the lamp is about 0.5 m from illuminated surface. A Honda EX 350 generator was used as a power-source. Moths attracted to the screen were collected into small glass tubes and pinned after killing with ethyl acetate.

Genitalia were prepared following the method described by Robinson (1976) and Traugott-Olsen, Nielsen, (1977). After maceration of the abdomen in 10% KOH and subsequent cleaning, male genital capsule was removed. The genitalia were studied and some morphological structures were sketched in glycerol before permanent mounting in Euparal. The aedeagus was removed and mounted alongside the genital armature. Genital capsule was stained with fuchsin and abdominal pelt with Chlorozal Black (Direct Black 38/Azo Black).

Forewing length is measured along the costa from wing base to the apex of the cilia (apex of the terminal fringe scales). For a wingspan, the forewing length was doubled and thorax width added.

The terminology used for morphological structures mostly follows that of Traugott-Olsen, Nielsen, 1977 and Kaila, 1999.

The type of the newly described species is deposited in the collection of The Natural History Museum, London, UK (formerly British Museum, Natural History)(BMNH).

DESCRIPTION

Family Elachistidae Bruand, 1850 Genus Stephensia Stainton, 1858, Stephensia armata Sruoga, new species (Figs. 1–4)

Type material: Holotype: male, Belize, Cayo Distr., Chiquibul Forest Reserve, Las Cuevas Research Station, 3–16 April 1998, R. Puplesis and S. R. Hill, genitalia slide No. 29591 (BMNH).

Habitat: At the collecting site (on hillsides and valley bottom) the forest has a greater proportion of evergreen species, e.g., Manilkara zapota, Calophyllum brasilense and Aspidosperma megalocarpon, although deciduous species such as Swietenia macrophylla and Terminalia amazonia are still an important component (Fig. 2). The majority of the vegetation is intermediate-age (ca. 30 yrs) secondary forest. The area receives between 1500 and 2000 mm of rain per annum (Puplesis, Robinson, 2000). Rainfall is not distributed regularly throughout the year for there are two dry seasons (from February to June and again for two to three weeks in August).

Fig. 2

Collecting site of Stephensia armata sp. n. at Las Cuevas Research Station, Belize (at the right side - the collector Simon R. Hill).

Description: Male (Fig. 3A). Forewing length: 3 mm. Wingspan: 6.6 mm. Head: ochreous white; background layer of frons scales with some metallic lustre; neck tufts matching head coloration but caudally dark ochre; labial palpi very short and straight, as long as the eye diameter; scape large and wide, about 3 times broader than flagellum, V. Sruoga and R. Puplesis pale ochre, with a few darker scales distally; flagellum unicolorous, dark brown-grey. Thorax and tegulae dark ochre. Forewing dark ochre but costal area grey-brown, and some grey-brown scales densely scattered distally; transverse fascia antemedian, white and straight; costal and tornal spots small and ill-defined, pale ochre; fringe scales dark ochre, slightly paler apically. Hindwing and its fringe grey-brown. Abdomen grey-brown on upperside, paler on underside; each segment with pale ochre scales distally; genital tuft pale ochre.

Fig. 3

Stephensia armata sp. n., holotype: A, external view; B, male genital capsule; C, same, aedeagus.

Female unknown.

Male genitalia (Figs. 3B, C and 4). Uncus very small. Gnathos oval; basal arms strongly sclerotized distally; arms not fused medially, with long extensions proximally; spines of gnathos long and stout. Valva short and slender, broadened basally; cucullus narrow, apically rounded. Valval process strongly sclerotized and fused with caudally projected, strongly sclerotized lobe (Fig. 4A) which possessing two or three stout teeth apically (Fig. 4B). Transtilla strongly reinforced. Juxta large; proximal part of ventral shield strongly sclerotized, with lateral extensions; lobes long, distally tapering, sparsely setose. Vinculum narrow, proximal area extended ventrally. Saccus very small, visible in lateral view. Aedeagus long and slender, strongly sclerotized, tapering into acute apex distally; caecum very long, with well-developed manica.

Fig. 4

Stephensia armata sp. n. male genitalia, holotype: A, basal area of valva; B, apex of valval lobe; C, vinculum and saccus in lateral view; D, basal arms of gnathos.

Distribution. Belize rainforest (Chiquibul) (Fig. 1).

Etymology: Armata (Latin)=armed; the name refers to the armed valvae (possessing 2–3 stout teeth).

Diagnosis: The new species is one of the most striking representatives of Stephensia (Elachistidae) in the remarkable forewing pattern with a single transverse fascia, the distinctively long and strongly sclerotized valval lobe, and very long lobes of juxta.

Among currently known congeneric American species, S. cunilae Braun (USA: Ohio, Kentucky, Indiana) and S. major (Kearfott) (USA: North Carolina) it also differs in the deep median split between the remarkably large juxta lobes, and in the reduced uncus.

Phylogenetically S. armata is markedly apomorphic.

DISCUSSION

During the last decade the taxonomy of the Elachistidae has got dramatic changes. Traugott-Olsen, 1995a, (1995b, 1995c, 1996) proposed the classification, introducing a considerable number of new generic names. Most of species, however, were assigned to the large genus, Elachista. The remaining species were scattered among small, often monotypic, genera. In general, in the recent classifications, the number of valid genera has varied between fifteen (Hodges, 1998) and twenty-five (Traugott-Olsen, 1995a, 1995b, 1995c, 1996). These unexpected and sudden changes in the taxonomy concept of the family were met with suspicion by most lepidopterists, and some doubts were expressed in unpublished communications. In the latest exhaustive worldwide treatment of the family by Kaila (1999) the most of genera were synonymized, and only three genera of the Elachistidae were recognized for the world fauna: Perittia Stainton, Stephensia Stainton and Elachista Treitschke. In the present paper we follow this concept of the family. We also think that the inclusive generic concept within Elachistidae would lead to a more stable nomenclature than would the alternative.

According to Kaila (1999), in male genitalia, Stephensia may be characterized by two apomorphic characters: 1) caecum of aedeagus much prolonged; 2) valval process membranous containing tongue-shaped extension. In the new species, armata, the caecum of aedeagus is very long and, therefore, remarkably well supports the concept of Stephensia. The valval process of armata is also with a large lobe-like extension and fits to Stephensia diagnosis. The undifferentiated male tergum 8 and the presence of a dorsal shield of juxta (i. e., the additional characters for Stephensia listed by Kaila, 1999) were found as characteristic for armata sp. n. too.

Other distinctive features, such as the strong sclerotization of valval process together with the stout teeth suggest that armata occupies a somewhat isolated phylogenetical position within Stephensia but are not referred by us as characters of a generic rank. However, following reviewers' comments, we agree that the sclerotization of valval process and the shape of uncus may be considered as unusual.

In order to preserve nomenclatorical stability, it is considered better to include the new species in Stephensia than to propose a new genus on the basis of the sclerotization of valval process or the reduced uncus. As morphologically remarkable and the first Stephensia from the tropical rainforest, its discovery begs several questions regarding the phylogenetic and biogeographic origins of the genus.