Acanthaclisis occitanica (Villers, 1789)

Badano, Davide & Pantaleoni, Roberto Antonio, 2014, The larvae of European Myrmeleontidae (Neuroptera), Zootaxa 3762 (1), pp. 1-71 : 47-49

Acanthaclisis occitanica (Villers, 1789)

( Figs. 2E , 24 )

The larva of this species was described for the first time in a pioneering work by Percheron (1833) as Myrmeleon libelluloides . However, the first rigorous account was later redacted by Brauer (1855b), also detailing its ecology and behaviour ( Brauer 1855b). This large species was treated many times ( Hagen 1873; Redtenbacher 1884; Steffan 1975; Willmann 1977; Gepp & Hölzel 1989; Gepp 2010; Krivokhatsky 2011). In the XIX century the larva of this antlion was repeatedly confused with Synclisis baetica , much more easier to find in the field ( Dufour 1854; Ferrari 1864; Girard 1875; Dubois 1899).

Examined specimens. Portugal. Estremadura, San Martinino , VII.1996 (A. Molinu), 2 L3 . Italy. Sardinia, Alghero (Sassari), Maria Pia , back dunes, IV.2008 (C. Cesaroni), 1 L3 ; same locality, XI.2009 (D. Badano), 1 L2. Sardinia, Spiaggia del Liscia (Nuoro), IX.2009 (L. Lenzini), 3 L3. Sardinia, Sa Tiria Posada ( Nuoro ), V.2006 ( R. A. Pantaleoni), 1 L2. Sardinia, Scivu, Arbus, back dune (Oristano), V.2010 (D. Badano), 1 L2 .

Description of 3 rd instar larva. Size (based on 6 specimens): BL 23.37 mm; HL 4.58 mm (4.43–4.89), HW 3.75 mm (3.69–3.92), ML 3.55 mm (3.42–3.72), HW/HL 0.82, ML/HL 0.78. General colouring grey with a dark pattern, ventral side pale with dark spots; head capsule with conspicuous dark markings on the dorsal and lateral sides ( Fig. 24c ), ventral side of the head pale with a dark area covering the mouthparts and isolated spots at the insertion of ventral setae ( Fig. 24d ); mandibles completely black; legs pale; setae of the body black. Head rectangular, a little longer than wide; anterior margin of the labrum with a cuneiform process bearing setae on the external margin ( Fig. 24b ); mandibles very strong, shorter than the head capsule, noticeably broader in correspondence of basal tooth, apical tooth at a different angle than the other teeth ( Fig. 24a ); interdental mandibular setae: (~2)(1)(1)(0); external margin of the mandibles covered by bristle in the basal half. Mesothoracic spiracles dark. Abdominal spiracles dark; VIII sternite with ventral stout digging setae; IX sternite rounded in shape, equipped with robust digging setae similar to those disposed on the previous sternite ( Figs 2E , 24e ).

Bio-ecology. The larvae of A. occitanica are typical inhabitants of back dunes with a relatively complex vegetation, characterized by the presence of bushes or trees, where the sand is rich in organic debris acquiring a dark colour. Nevertheless this antlion is also found in sandy habitats far from the coast such as fluvial deposits, steppes and relict dunes. The larvae are often hidden among roots, near tree bases or under shrubs.

Distribution. Widespread in the western Palaearctic. This species was notably reported from coastal sites on the North and Baltic seas, where it is now extinct ( Brauer 1855b).

Remarks. A. occitanica is the only member of the genus in western Europe while in Russia it is also present the closely related A. pallida , whose larva was described by Luppova (1969); according to this account, the larvae of the two species apparently differ only in the colour of the mandibles.

Figures

FIGURE 2. IX and VIII abdominal sternite of 3rd instar larvae of Palparini, Myrmecaelurini, Nesoleontini and Acanthaclisini. A, Palpares libelluloides; B, Myrmecaelurus trigrammus; C, Cueta beieri; D, Cueta lineosa; E, Acanthaclisis occitanica; F, Synclisis baetica. Scale bar: 1 mm.

FIGURE 24. Acanthaclisis occitanica (Villers, 1789), 3rd instar larva (Italy: Sardinia, Spiaggia del Liscia). Dorsal (above), ventral (middle) and lateral (below) view; a–e: diagnostic characters, see species description. (photo by C. Cesaroni).