Sialis (Protosialis) casca, ENGEL & GRIMALDI, 2007

ENGEL, MICHAEL S. & GRIMALDI, DAVID A., 2007, The Neuropterid Fauna of Dominican and Mexican Amber (Neuropterida: Megaloptera, Neuroptera), American Museum Novitates 3587, pp. 1-60 : 7-10

Sialis (Protosialis) casca , new species figures 1–3

DIAGNOSIS: The orange coloration of the head and pronotum and narrowed costal area with a reduced number of costal crossveins indicate this to be a species of the subgenus Protosialis . For Protosialis species the presence of only three costal crossveins is unique while the black markings on the head are similar to that seen in Sialis (Protosialis) flammata (Penny) but are rounded in the fossil (not flamelike as in S. flammata ).

DESCRIPTION: Forewing length (preserved) 7.7 mm, (estimated: from bent forewing) 8.4 mm; total body length 7.6 mm ( fig. 1 ). Head and pronotum orange with black markings; antennae black; head with black markings along margins of eye and extending posteriorly near to posterior border of head, black extended medially but not reaching midline, borders of markings rounded (not flamelike). Apical segments of maxillary palpi with medioapical tooth. Ocelli absent. Pronotum apparently twice as wide as long, remainder of thorax dark brown. Protibia, mesofemur, mesotibia, and metatibia black, remaining leg segments whitish; fourth tarsomere bilobed. Wing membranes fuscous; veins dark brown to black; forewing with costal area distinctly narrowed just before middle of wing; three costal crossveins, distal two veins distinctly oblique (i.e., not perpendicular to C or Sc); distal r-rs crossvein meeting R 2+3 slightly distad to R 2+3 / R 4+5 fork; posterior branch of R 4 /R 5 separating near wing apex (i.e., distad R 2 /R 3 branching); outer series of gradate crossveins confluent ( figs. 2, 3 ). Abdomen slightly distended and bent ventrally near

TABLE 5 Named Fossil Sialidae midpoint; apparently light brown; apex of abdomen curled under, with genitalia pointed anteriad.

HOLOTYPE: Male ; MACT-2090 ( fig. 1 ), Miocene amber of the Dominican Republic.

ETYMOLOGY: The specific epithet is taken from the Latin word cascus (meaning ‘‘old’’) and is a reference to the age of the specimen.

ORDER NEUROPTERA LINNAEUS FAMILY MANTISPIDAE LEACH

The mantispids are perhaps one of the most instantly recognizable of neuropteran families and consist of approximately 400 species worldwide. Their convergent form with mantises (Mantodea) of an elongate prothorax and raptorial forelegs is remarkable. Adults tend to be diurnal and are often found on flowers, although a few lineages are nocturnal or crepuscular. Some species are brightly colored and appear to mimic social, aculeate Hymenoptera . The most basal mantispids, the Symphrasinae , have sedentary larvae that are generalist predators found in the nests of social Hymenoptera , particularly vespids, or burrows of scarab beetle larvae. Similarly, the Calomantispinae appear to be generalist predators although the larvae of at least one studied species are ambulatory. The subfamily Drepanicinae is entirely unknown biologically. The largest subfamily, the Mantispinae and the subfamily to which the fossils described below belong, are specialized, obligate parasites of spiders, and the first-instar larva either boards a female spider and enters the egg sac as it is constructed, to feed on the eggs, or it searches directly for an egg sac. Later larval

TABLE 6 Named Fossil Mantispidae a instars are relatively immobile. Pupation occurs within the host egg sac. Adults are actively predaceous on a variety of other insect groups. Redborg (1998) has reviewed the available information on the remarkably specialized biology of Mantispinae . Although Willmann (1990) included the Rhachiberothinae in Mantispidae , we follow Aspöck and Mansell (1994) and Aspöck et al. (2001) by considering this group as allied to the Berothidae .

The geological history of the Mantispidae has only recently begun to come together. Previously there were nine fossil species described from deposits ranging from the Early Jurassic to the Miocene (table 6: Wedmann and Makarkin, 2007), although the exact systematic position of some of these taxa is not entirely certain. Only two mantispid species had been discovered in amber until this time, but one is likely not a member of this family. Walfera venatrix (Whalley) was discovered in amber that had washed up on the eastern shore of Britain and presumably was derived from the Baltic amber deposits of the blaue Erde. The identity of Whalfera , however, has been questioned by many, and the genus is very likely a rhachiberothid ( Aspöck and Mansell, 1994; Engel, 2004b; Grimaldi and Engel, 2005; Wedmann and Makarkin, 2007). The only other amber mantispid is Feroseta priscus Poinar in Miocene Dominican amber ( Poinar, 2006). Herein we report two further, definitive mantispids in Cenozoic amber from the Western Hemisphere. Spiders are common in Tertiary ambers of North America (e.g., Wunderlich, 1988; Penney, 1999), and it is therefore perhaps not surprising that their parasites would also eventually be discovered.

Figures

Fig. 1. Photomicrograph of holotype of Sialis (Protosialis) casca, new species (MACT-2090).

Figs. 2, 3. Holotype of Sialis (Protosialis) casca, new species (MACT-2090). 2. Dorsal aspect. 3. Left lateral aspect.