446

Palingeniidae ALBARDA (in Sélys-Longchamps), 18881

In Europe represented by the nominotypical genus Palingenia BURMEISTER, 1839 Palingenia BURMEISTER only, world wide 7 genera comprising altogether about 30 species. Two subfam- Palingenia BURMEISTER, 1839; Handb. Entomol. 2 (2), p. 802 ilies are usually recognized: Palingeniinae ALBARDA (in Sélys-Longchamps) in the Old World (with a southern Type-species: longicauda OLIVIER, 1791; extension into the Australian region, Papua-New subsequent designation by Hagen [in Walsh] (1863, Guinea)2, and monotypic Pentageniinae MCCAFFERTY, Proc. Entomol. Soc. Philadelphia 2: 173) 1972 (distributed in the Nearctic and Neotropic re- gions)3. Besides a revised cladogram of the superfam- DIAGNOSIS. Very large (largest in the world ily (Scaphodonta) by McCafferty within extant groups), ranging in body length 25-40 (2004, Entomol. News 115, 2: 87), no cladistic analy- mm, in length of fore wings up to 30 mm. Larvae of sis is available at present, but delimitation of the family the burrowing type with pointed processes on the and composition of genera is well established. Palin- outer margin of clypeus, genae, mandibular tusks and geniidae are characterized by the following autapo- fore tibiae. Tusks without terminal spine-like setae. morphies: Prosternum in all stages rather narrow, First gill small and vestigial, not fringed, with large an- bases of fore coxae contiguous or nearly contiguous terior and narrow, finger-shaped posterior lobe. Gills at their articulation with the prosternum (furcae of 2-6 forked and fringed marginally. Cerci and parac- meso- and metathorax not modified). Larval ercus well developed, paracercus as long as about 1/3 trochanters with a specialized condylus on distal edge. of cerci. In imagines mesonotal suture extremely Fore legs and mandibles adapted to burrowing and ex- stretched posteriorly. Longitudinal veins of fore wings hibiting a well defined arrangement of setae on ventral not in close proximity, bifurcation of vein MA in the side of mandible, inner side of femora and fore tibiae. distal half of the wing. Fore legs in female subimagines Maxillary and labial palps 2-segmented, gill 1 vestigial, with a single blunt claw, with 2 blunt claws in males. and paracercus in imagines and subimagines reduced Forceps with 6-7 segments, ultimate segments re- at least in males (see Kluge 2004: 248, for details). duced or vestigial. Penis deeply cleft with widely sep- Imagines (at least in Palingenia and Plethogenesia arated tubular lobes, titillators absent. Paracercus ULMER, 1920) with conspicuous rudiments of gills 2- vestigial but present in both sexes. Imaginal stage usu- 7 also in the subimaginal and imaginal stage (Štys & ally suppressed in females. Soldán 1980, Acta Univ. Carolinae, Biol., 1978: LARVAE. Clypeus with 4-5 pointed processes, wider at 409). Emergence highly synchronized at least within base than at apex. Genae with 2-3 pointed processes. Palingeniinae. Suppression of the imaginal stage in Labrum rounded, with marginal rows of bristles. females represents a further prominent autapomor- Mandibles strong, hypertrophied and protruding in phy. Genera and species of Palingeniidae of Europe, dorsal view. Mandibular tusks with long, conspicuous Asia and Papua-New Guinea have been revised and stout spines, outer and inner incisors approximately keyed by Demoulin (1965, Nova Guinea, Zool. 33: equal in length. Superlinguae of hypopharynx twice 305), Afrotropic (Madagascar) representatives by De- longer than lingua, with long bristles along margin (lin- moulin (1952: Bull. Inst. Roy. Sci. Nat. Belg. 28, 13: gua only with short setae). Maxilla pointed, covered 10), McCafferty (1968, Entomol. Rec. J. Var. 80: with numerous bristles and two slender spines api- 293), Sartori et al. (1996 Proc. XXth Int. Congr. En- cally. Maxillary palps 3-segmented. Glossae narrow, tomol. : 93), and Sartori & Elouard (1999, Rev. Su- pointed, shorter by 1/3 than paraglossae. Outer mar- isse Zool. 106, 2: 325) and recently listed by gin of paraglossae rounded, inner margin straight. Bar ber-James & Lugo-Ortiz (2003: 156). Molecular Labial palps 2-segmented, segment 1 narrow, three taxonomic aspects of Palingeniidae (Plethogenesia) times longer than wide, segment 2 club-shaped, have been discussed by Ogden & Whiting (2003, En- dorsoventrally flattened, with bristles along margin. tomol. Abhandl. 61, 2: 126; 2005, Molecular Phylo- Fore tarsi of male and female larvae dissimilar show- gen. Evolut.37: 625). ing sexual dimorphism (Soldán 1981, Acta Entomol. Bohemoslov. 78: 140). Tarsal claws without teeth,

1 For authorship of the family see Peters & Hubbard (1977, Eatonia 23: 1). 2 Occurrence of Palingeniinae in continental Afrotropic region is doubtful (cf. Demoulin 1965, 1970). 3 Contrary to crepuscular Palingeniinae (only fore legs of = functional), long-lived imagines of monotypic Pentageniinae possess all legs functional, wing venation related to and paracercus subequal to cerci in the female imaginal stage. Larvae are characterized mainly by specialized spine-like setae on mandibular tusks and outer margin of fore tibiae without denticles. Pentageni- inae are sometimes considered a separate family (or included in Ephemeridae). See discussion in McCafferty (1972, 1975), Edmunds et al. (1976) and Edmunds & McCafferty (1996: 73). PALINGENIIDAE 447 hooked on fore legs, claws on middle and hind legs ines molt into imagines and start patrol flight. Phase slightly bent, as long as 1/2 of tarsus. Gill 1 vestigial, 3 (t + 20-30 min.) – female larvae rise to the water without tracheization. Gills 2-7 consisting of an ante- surface and subimagines emerge, copulation follows rior and posterior branch with marginal fringes, the almost immediately (up to 30 males attempting to posterior part shorter and more rounded at apex. copulate with a single female). Phase 4 (t + 40-50 Branches of gill 7 approximately equal in length and min.) – females leave the male swarms and move to pointed apically. In first instar larvae (P. sublongi- the middle of the river, where they in turn fly up- cauda) antennae and cerci 5-segmented, mandibles stream. Phase 5 (t + 60-90 min.) – the males carry without tusk, fore tibiae without spines and tibia of on swarming until they die of exhaustion, females middle legs with rod-shaped appendage. continue in upstream compensatory flight and ovipo- sition. IMAGINES. Compound eyes dark grey or black, ocelli whitish or yellowish. Wings grey or brownish grey, REMARKS. Identification is not infrequently difficult and unicolorous. The margins of fore and hind wings with rests mostly on the outline shape of male genitalia, a large number of free veins connected by short cross usually in combination with colour pattern on abdom- veins. In fore wings vein CuA without furcation, veins inal terga. Although penis lobes lack distinct sclerites, MP1 and MP2 not in close proximity, at least three they are usually diagnostic: outline in ventral and es- long free veins in anal field A1. Fore tibia of male pecially lateral view, length/width ratio, and their ori- imagines 2.5 times longer than femur. In female entation in relation to body axis. Subimagines are subimagines tarsi of all legs segmented, middle and mostly very similar to imagines, male genitalia diag- hind legs of males and females with well-developed, nostic for the genus. Contrary to extralimital species not reduced, tarsal claws. Eggs biconvex, lens-shaped, (showing peculiar cubito-anal venation; Demoulin about 360-420 x 290-375 µm in size, with a single 1965, Sartori 1992) the European species probably micropyle and smooth surface (P. longicauda, P. sub- cannot be distinguished using wing venation. Egg longicauda). KCT’s or anchor like structures are miss- shape (so far known) is typical for the family but no ing, the egg is completely wrapped by an exochorion diagnostic characters on species level have been ob- that forms a continuous envelope, fixing the egg to served. Identification of larvae is difficult and fre- the substratum in the form of an adhesive membrane quently doubtful (colouration, shape of gills 1 and 7 after oviposition (Kosova 1967, Zool. Zh. 46: 1858; and colour pattern). Due to mass mating flight and Gaino & Bongiovanni 1993, Int. J. Morphol. considerable size, (sub)imagines of Palingenia were & Embryol. 22, 1: 41; Landolt et al. 1995, 1997). probably the first mayflies ever noticed by man. Per- haps first recorded already by Aristotle of Stageira DISTRIBUTION. Palaearctic and Oriental, data from the (384-322 B.C.), descriptions have been published by Afrotropic region (P. apatris DEMOULIN, 1965) are doubtful (see Demoulin 1965, 1970). Julius Caesar Scaliger in 1557, by Augerius Clutius (1634) and by Jan Swammerdam (1675) in his fa- BIOLOGY. Larvae are fossorial, burrowing in clayey, mous “Ephemeri Vita” (cf. Arvy & Peters 1975, muddy and silt substrata and constructing U-shaped Eatonia Suppl., 1: 1; Mol 1984, Proc. IVth. Int. Con- tubes, in which a water current is created by move- fer. Ephemeroptera., p. 3 and Soldán 1997, Ephe - ments of tracheal gills 2-7 (cf. Edmunds & McCafferty meroptera & Plecoptera: Biol., Ecol. Syst., p. 515). 1996, Entomol. News 107, 2: 73). They feed on fine particles filtered by mouthparts (and probably also by . The genus Palingenia is well defined at bristles on legs). Larvae prefer unpolluted, large low- present and distinct from other genera within Palin- land rivers with moderate to fast current velocity and geniidae. Imagines have been keyed by Demoulin relatively high oxygen content. Imagines are crepus- (1965, Nova Guinea, Zool. 33: 306) and show close cular, emergence is highly synchronized (mostly in the relationship to the extralimital monotypic genus Mor- evening, but observed also in the morning) and con- togenesia LESTAGE, 1924. Soldán (1978, Acta Ento- centrated to 2-3 weeks a year. Life cycle of the semi- mol Bohemoslov. 75: 281) provided a key for voltine type, larval development lasts probably for 3 Palingenia (imagines and – so far described – larvae). years. Female subimagines usually do not moult, mat- EXTRALIMITAL SPECIES ing and oviposition take place in the subimaginal stage Palingenia anatolica JACOB, 1977; Entomol. Nachr. 21: (neoteny). Swarming consists of 6 phases: Phase 1 177 (Turkey) (time 0) – males moult on the water surface and fly to Palingenia orientalis CHOPRA, 1927; Rec. Indian Mus. 29: the river bank (alighting either on the ground or on 104 (Iran) [= P. longicauda sensu Gravely (1920, Rec. vegetation). Phase 2 (t + 2-5 min.) – male subimag- Ind. Mus. 18: 138; nymph)]4

4 = Palingenia jordanica BODENHEIMER, 1935 (in Meyer), Anim. Life in Palestine, Jerusalem, p. 506 [nomen nudum]; see also Sartori (1992, Rev. Suisse Zool. 99, 4: 852).