Peltasta, Bidzilya, 2010

Bidzilya, O. V., 2010, A new genus of gelechiid moths (Lepidoptera, Gelechiidae) from Central Asia, Zootaxa 2502 (1), pp. 47-55 : 48-50

Peltasta gen. n.

Type-species: Borkhausenia zonula Gerasimov, 1931 .

Description. Head: Cream, frons smooth-scaled, lateral sides and termen covered with slightly raised scales. Labial palpus strongly upcurved; segment 2 slender, smooth-scaled, cream; segment 3 approximately as long as segment 2 or slightly shorter, acute. Ocelli absent. Proboscis well developed, squamose at base. Antenna black, nearly two-thirds length of forewing. Thorax: Forewing broad, ovate, length 6.3–8.4 mm; venation with Sc, R 1 –R 4 to costa, R 5 to termen near apex, M 1 –CuA 2 to termen; M 1, CuA 1 and CuA 2 separate; 1A+2A to dorsum; cream or ochreous-brown, with basal and sub-apical transverse fasciae or bicoloured with cream costal and brown dorsal halves, sometimes uniform with dark veins (some forms of B. gershensonae ). Hindwing trapezoidal, broad, terminal excavation indistinct; venation with R 1 anastomosed with Sc near wing base; Sc +Rs to costa, R5 to costa near apex, M 1 –M 3, CuA 1, CuA 2 and 1A+2A to termen, M 3 and CuA 1 connate, from corner of cell; apex nearly round or weakly pointed. Frenulum of male simple, with one acanthus, frenulum of female with three acanthae. Abdomen: Segment VIII in male fused, sternum VIII simple, unmodified. Male genitalia with uncus a prolonged, well developed flap, with long lateral setae. Gnathos a strong, slightly curved hook. Tegumen weakly prolonged, nearly at right angle, with deep, broad anterior emargination, lateral folds well developed. Valva divided into three lobes: cucullus (dorsal lobe) digitate, moderately broad, with more or less developed membranous flap on ventral margin, densely covered with long hairlike setae in apex or distal 1/3 length, apex rounded; sacculus (ventral lobe) 1/3 to 2/3 length of cucullus, wide basally, narrow distally; valvella (medial lobe) ½ to ¾ length of cucullus, narrow, digitate. Vinculum narrow, band-shaped, with well developed, broadly rounded saccus. Phallus rounded basally, strongly swollen, distal portion straight or weakly curved, apex rounded with small downward curved, beakshaped tip; ductus ejaculatoris with long, strongly sclerotized lamina. Female genitalia with segment VIII simple, distinctly broader than long, tergum membranous except for strongly sclerotized band-shaped anterior margin; sternum VIII evenly sclerotized, posterior margin broadly invaginated; papilla analis broadly dissected laterally, divided into paired subtriangular ventral lobes and narrow, sickle-shaped, densely setate dorsal lobes; ventral lobes bearing strongly modified spatulate or hook-shaped scales (e.g., P. gershensonae ); apophyses anteriores very short, apophyses posteriores straight, dilated apically, longer than segment VIII; antrum membranous, narrow, tubular or triangular, membranous or distinctly sclerotized (e.g., P. pseudozonula ); antrum ostium bursae subcircular or cordate, opened near anterior margin, surrounded by sclerotized patches with delicate honeycomb pattern in P. gershensonae ; ductus bursae short with well developed narrow or relatively broad sclerotized colliculum, posterior half with additional lateral sclerotization (e.g., P. gershensonae ) or with irregularly shaped, serrate sclerite ( P. zonula ); corpus bursae subovoid or round; signum a large, elongate subrectangular or irregularly shaped plate, slightly or distinctly constricted in middle, with dense lateral spikes in P. gershensonae , with a pair of subterminal folds, either transversely finely serrated or simple.

Distribution. Turkmenistan, Uzbekistan, SE Kazakhstan, Iran, Mongolia.

Biology. Early stages and host-plant unknown.

Etymology. The generic name is derived from the Latin peltastae meaning warriors, armed with shields, and refers to the strongly modified, sclerotized scales on the papilla analis in the female genitalia.

Remarks. The subdivision of Gelechiidae into subfamilies and tribes remains somewhat enigmatic. Meyrick (1925) divided the family into nine genus-groups. Subsequent authors accepted this system in general, proposing changes primarily in the number of genus-groups (from 4 to 11) and their rank (subfamilies or tribes). Hodges (1998) recognized four subfamilies - Physoptelinae, Gelechiinae , Pexicopiinae , and Dichomeridinae - based on the structure of the sternal support system of the abdomen, but this proposed arrangement did not receive widespread usage. Ponomarenko (2005) recently divided the family into five subfamilies based on an analysis of characters considered most important for phylogenetic reconstruction, including the musculature of the male genitalia. However, the definition of some tribes and subfamilies remains unclear in some aspects, and there still are unresolved problems. Ponomarenko (2005) united Anomologini , Apatetrini , Aristoteliini, and Pexicopiini into the subfamily Anomologinae based on characters including the dilated anterolateral parts of the tegumen and the valva fused with the tegumen. A second large clade comprises the subfamilies Gelechiinae (with tribes Gnorimoschemini , Gelechiini and Litini ), Anacampsinae (with tribes Anacampsini and Brachmiini), and Dichomeridinae (with tribes Dichomeridini, Chelariini and Anarsiini) based on the elongate anterolateral parts of the tegumen ( Ponomarenko 2005: 89, fig. 102). The characters used for separating subfamilies and tribes are often somewhat ambiguous; in many cases it is difficult to determine whether the valva is fused with the tegumen or only closely connected to it, and whether the anterolateral parts of the tegumen are elongated. The definitions of tribes in Ponomarenko's system are clearer, although no autapomorphy has been found for Gelechiini , and hence it is defined only by the absence of Gnorimoschemini characters. The diagnosis of others tribes and subfamilies (with the possible exceptions of Gnorimoschemini and Dichomeridinae ) are based mainly on combinations of characters that are difficult to formalize and use in a cladistic analysis.

Current problems in Gelechiidae systematics can be attributed to a variety of factors, but probably most importantly to the high degree of variation in the male genitalia. The numerous cases of parallel development of different non-homologous characters and numerous cases of convergence are difficult to recognize, and these features create difficulties when applying cladistic methods of morphological analysis. A more “natural” classification for the family may be derived using a complex approach that relies on traditional morphological methods in combination with the study of functional morphology of the male genitalia, augmented by molecular data, as was proposed by Ponomarenko (2005). When accompanied by data on biogeography and host-plant relationships, these analyses can produce robust results. Unfortunately, our knowledge of Gelechiidae in many regions of the world is still far from complete. There is little doubt that many genera and species remain to be discovered, especially from the tropical regions, and these missing data and taxa make it nearly impossible to build a convincing classification for the family today.

Because of these shortcomings in our knowledge, many genera often are placed in tribes based on an artificially selected combination of characters. It is relatively easy to assign genera to tribes in which their relatives are obvious on the basis on morphological similarity of the genitalia. But in other cases the position of genera within the family, both existing or newly described, is difficult based on the traditional study of genital morphology. The systematic position of such genera may be defined more convincingly through their examination in global or broad regional revision works.

The position of Peltasta within Gelechiidae is difficult to define. It is easily recognised by the characteristic divided lobes of the papilla analis which bear strongly modified setae. This character is unique within Gelechiidae . One can suppose that strongly modified papilla analis suggests a unique mode of oviposition, but field observations are required to confirm this hypothesis. In any case, this character cannot be used to define the position of the genus within family because it is likely a narrow specialization. Furthermore, neither the short apophyses anteriores nor the specific shape of the signum can be used to clarify relationships of new genus. Short apophyses, along with a narrow band-shaped tergite VIII, are observed by Chrysoesthia Hübner, [1825] (Apatetrini) as well as in Ornativalva Gozmány, 1955 , and Bryotropha Heinemann, 1870 , which are members of the tribe Anomologini (=Aristoteliini) ( Ponomarenko 2005). The last two genera also have a signum similar to that of Peltasta . However, the adaptive value of these characters is unclear, and they are likely unimportant for establishing phylogenetic relationships between gelechiid genera ( Ponomarenko 2004). On other hand, apomorphies such as the posteriorly sclerotized ductus bursae and sternite VIII with a honeycomb sclerotization are more important for phylogeny reconstruction. Both characters are common in some Gelechiini genera ( Athrips Billberg, 1820 , Parapsectris Meyrick, 1911 ), but they have never been observed in Anomologini . Honeycomb sclerotization in the female genitalia is widely distributed in Gnorimoschemini as well, but members of this tribe differ considerably from Peltasta in the male genitalia. So the female genitalia of the new genus show a closer relationship to Gelechiini . A basally bulbous aedeagus, strong and moderately short, hook-shaped gnathos, well developed sacculus, and platelike uncus in the male genitalia are found in genera scattered throughout Anomologini and Gelechiini . On other hand, a strongly differentiated valva that is basally dilated, as well as the presence of well developed lateral flaps of the tegumen, are more typical for Gelechiini . The first character is shared with Gelechia Hübner, [1825] , Neofriseria Sattler, 1960 and Mirificarma Gozmány, 1955 , whereas the latter character is a characteristic feature of Athrips and Parapsectris . In contrast to Gelechiini , male genitalia of Anomologini usually are characterized by a simple valva of equal width ( Aristotelia Hübner, [1825] , Megacraspedus Zeller, 1839 ) and the absence of lateral flaps of the tegumen. The valva in Peltasta does not appear to be broadly fused with the tegumen. The latter character state and the absence of a juxta are considered by Ponomarenko (2005) as a diagnostic feature of Gelechiini , are not typical of Anomologini (Aristoteliini sensu Ponomarenko 2005). These considerations are simple in many aspects, but based on them, the new genus placed tentatively in Gelechiini rather than Anomologini until additional data become available to correct the current placement of Peltasta . The new genus occupies a rather isolated position within Gelechiini , having a rather unique combination of the genitalia characters. It is placed provisionally near Athrips and Parapsectris based on the strongly developed lateral folds of the tegumen (see Huemer & Karsholt 1999, fig. 157 for comparison). The female genitalia of these genera also are rather similar (see above). In contrast, the strongly differentiated valva suggests a relationship with Neofriseria . Probably all these genera, along with the Afrotropical genus Schizovalva Janse, 1951 , constitute a separate clade within Gelechiini , but further study is needed to test this hypothesis.