Contributions to Zoology, 81 (1) – 2012Valerio Scali; Liliana Milani; Marco Passamonti: Revision of the stick insect genus Leptynia: description of new taxa, speciation mechanism and phylogeography

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Leptynia attenuata attenuata, Pantel 1890, new rank

The subspecies embodies specimens collected primarily in the patria typica of São Fiel (Castelo Branco, Portugal) as indicated by Pantel (1890) in his seminal paper, as well as samples collected in nearby locations (see map, Fig. 1; Table 1), shown to cluster together by molecular analyses (Passamonti et al., 2004). Its definition resides on the genetic distances and the likely phyletic relationships, based on the mitochondrial cox2 gene (Fig. 2) and allozyme data, respectively. Its karyotype obviously fits in L. attenuata for number, general structure and sex-chromosome formula (2n = 36, XX/XY; Fig. 3C); its fine structural differentiation from the karyotype of the two new subspecies is not a sound one.

From size ranges of both males and females it can be seen that L. attenuata attenuata specimens are among the largest of the species.

Male terminalia present two traits worth mentioning: the swollen base of the subanal vomer and its common peculiar narrowings subdividing it into three-four parts; however, these traits are not subspecific diagnostic features being also shared by the other two:

- An apparently sounder characterizing trait is given by the small tooth projecting from the base of the cercus arm: the tooth (about 0.3 mm long) is here slender, almost cylindrical with a blunt apex (Fig. 8B).

- No peculiar features have been observed in the females; however, the subspecies appears to be characterized by the lowest egg operculum angle recorded among Leptynia taxa (Table 2), its egg capsule being cut almost perpendicularly by the opercular opening (Fig. 9E).

- Owing to the above described morphological traits, we choose a male as reference specimen from Portalegre, whose main parameters are recorded in Table 4. From the direct inspection of the reference male we can see that its left foreleg is missing and that its general colouration is deep brown. The compound, hemispherical eyes are uniformly tinged by a deep brown pigment; beyond the eye the brown pigment draws two stripes on each side of the head, the higher being larger. From the head vertex a narrow median brown line starts to continue also on the thoracic and abdominal tergites. On each side the median line is encircled by a brown patch on the pronotum and paralleled by a thick brown stripe along the thoracic and abdominal tergites. The whole ventral side and the dorsal areas free from the brown pigment, are of a light canella colour.


Table 4. Holotype and paratype parameters and characterizing features of Leptynia attenuata subspecies and L. annaepaulae sp. n. Body length (in mm) does not include antennae and cerci. * = reference male of our collection; h = holotype, male; p = paratype, male for L. attenuata attenuata, female for L. annaepaulae; R = right; L = left. In the ‘hind femur reach’ column the ordinal refer to abdominal tergites.


Table 5. Diagnostic value of analyzed metric traits of Leptynia. The bold character indicates the compared taxon. + = diagnostic trait; o = not diagnostic trait.

- As in most L. attenuata specimens a subtle but neat median carina is noticeable on the meso- and meta-notum; a similar carina is also found on the anal, 10th, abdominal tergite, which, as mentioned above, even shows a wide, shallow incision (Fig. 8B). The ventral side of the male terminalia bears the most characteristic traits of the subspecies, since the subanal vomer possesses a characteristic swollen base and the cerci a typical slender tooth of appropriate size for the subspecies (Fig. 8A-B).

Derivatio nominis. The indication of the subspecies directly derives from the nomenclature rules, because its populations just occupy the area from which the species L. attenuata was first described by Pantel (1890).