Introduction
The genus Pycnodictya Stål, 1873 is a member of the subfamily Oedipodinae. At present it includes 14 species, one of which contains two subspecies (Eades et al. 2016), mainly distributed over the Afrotropical region (Johnston 1956, Dirsh 1965), with three species (P. dentata Krauss, 1902; P. galienieri Reiche & Fairmaire, 1849; P. gracilis Uvarov, 1936) reaching the Arabian Peninsula (Popov 1980, Ingrisch 1999, Eades et al. 2016).
Pycnodictya is arguably one of the rarer but morphologically distinct genera in the Oedipodinae. However, its species are not easily distinguished morphologically as many previous descriptions considered the color of hind wing and leg as main diagnostic characters (Uvarov 1929). Pycnodictya is unique in having an expanded lower marginal area of the hind femur, by which it can be easily distinguished from related genera of Oedipodinae, such as Chloebora and Scintharista described by Saussure in 1884 (Dirsh 1965). Generally most Oedipodinae have brightly colored hind wings, are characterized by the absence of a prosternal process, the hind legs are missing an external apical spine at the knee and stridulatory serration on the inner surface of hind femur, and by presence of an intercalary vein in medial area of tegmina and the vertical frons (Bolívar 1876, Siddiqui and Shamim 2013).
Previously, the subfamily Oedipodinae was represented in Egypt by 44 species and subspecies, belonging to five tribes: Acrotylini, Epacromiini, Locustini, Oedipodini, and Sphingonotini (Abdel-Dayem et al. 2005, Haggag et al. 2008, Haggag 2011) The genus Pycnodictya is currently listed under Oedipodinae without assignment to any of the tribes (Eades et al. 2016); in this article, the tribe Locustini is proposed for this genus following Johnston (1956), who used tribe names as group names, and included Pycnodictya in the group Locustae (valid tribe Locustini).
Pycnodictya was established by Stål (1873) to include P. obscura Linnaeus, 1758 and P. rosacea Serville, 1838, but the latter has been recently considered a synonym of the first (Eades et al. 2016). Some species of this genus are only known by only one of the two sexes and descriptions are often based upon a single specimen, as for P. citripennis Saussure, 1888; P. dentata Krauss, 1902; P. herero Karny, 1910; and P. kelleri Schulthess, 1894. Thus a revision of the genus including a key to the species is necessary.
Sporadic faunistic investigations had been made to record Egyptian insect species in different regions of the country. Some information about the insect fauna of Gabal Elba was reported by Hassan and Fadl (2000); however, they did not record Pycnodictya galinieri (Reiche & Fairmaire, 1849).
Gabal Elba covers approximately 10,000 km2, includes a group of six mountains, and is considered a distinct phytogeographic region of Egypt (Al-Gohary 2008). Moreover, it is considered to be a transitional zone between the Afrotropical and the Palaearctic biogeographical regions with a special ecogeographical area located in Egypt that lead to its declaration as a natural protectorate in 1984 (Hassan and Fadl 2000).
This contribution is the first record for the Afrotropical genus Pycnodictya Stål from Egypt. Based on microscopic observations of external morphological characters and a comparison to earlier literature dealing with the description of different species of this genus, especially from East Africa and Yemen (Ingrisch 1999), the available band winged specimen was identified as P. galinieri galinieri (Reiche & Fairmaire), which was described originally from Ethiopia and has been recorded further from Eritrea, Kenya, Oman, Somalia, South Africa, Sudan, Tanzania and Yemen (Johnston 1956, 1968; Dirsh 1965; Popov 1980; Ingrisch 1999; Eades et al. 2016).
Discussion
The classification of Egyptian Oedipodinae species was previously reviewed by Abdel-Dayem et al. (2005) and Haggag et al. (2008), and tribe Epacromiini was revised under Acridinae by Haggag (2011). The genus Pycnodictya belongs to the subfamily Oedipodinae with its brightly colored hind wings, vertical frons, and by the presence of an intercalary vein in medial area of fore wings. Also it lacks the prosternal process of other Acridid subfamilies (e.g. Calliptaminae, Cyrtacanthacridinae and Eyprepocnemidinae) and stridulatory serration on the inner surface of hind femur of other subfamilies (e.g. Gomphocerinae and Eremogryllinae).The genus Pycnodictya is recorded here as its subspecies P. galinieri galinieri and new for the Egyptian fauna from Gabal Elba.
The expanded lower marginal area of the hind femur is very characteristic for Pycnodictya by which it can easily be separated from related genera such as Chloebora Saussure, 1884 and Scintharista Saussure, 1884 (Dirsh 1965).
The different species of the genus Pycnodictya are similar to one another in general appearance, and the most features used for their identification are the color of the hind wings and hind legs, which are easily viewed by eye (Uvarov 1929, Ingrisch 1999). The previous description of P. galinieri by Saussure (1884) is superannuated and insufficient but recognizable, and thus, a description of the Egyptian subspecies is given in this paper with additional line drawings and photographs that are not available elsewhere. Pycnodictya galinieri galinieri is well-differentiated from other species of the genus by its characteristic hind wings with orange red bases, moderately narrow dark band with an anterior projection that is separated from the posterior margin, and the clearly dentate anterior margin of the pronotum. In addition, the hind tibia is blackish violet with a yellowish basal ring and the hind femur is blackish on its inner side.
Pycnodictya galinieri has a dentate anterior margin of pronotum resembling the situation in P. dentata Krauss, 1902 but lacks the sinuated posterior lower angle of the pronotal lateral lobes of the latter. However, P. kelleri Schulthess and the other subspecies P. galinieri citrina Kevan, 1961 described from Somalia and restricted to it (Eades et al. 2016), differentiated well from P. galinieri galinieri with their sulphorous or yellowish wings, respectively. Only the two species P. diluta Ramme, 1929 and P. zinae Uvarov, 1949 resemble P. galinieri in the purplish hind tibia, but P. diluta with disappeared fascia of the hind wings and P. zinae with crested pronotal median carina. Moreover, P. gracilis Uvarov and P. kilosana Miller, 1929 distinguished from P. galinieri as their hind tibia is honey yellow or light brown not blackish violet as the latter.
Pycnodictya galinieri is widespread along the eastern part of the African continent. The high mobility of Oedipodinae as very strong fliers (Alexander 1964) may explain the wide distribution of P. galinieri from South Africa to Egypt. It is not clear, whether the subspecies has so far been overlooked in Egypt or whether it has expanded its range. The new finding and previous new records from Egypt (Haggag et al. 2008, Haggag 2011) highlight the importance of making a thorough survey of Acridoidea in diverse regions of the country.