Ceraclea (Ceraclea) megalophyllon, Yang & Hu & Morse, 2020

Yang, Lian-Fang, Hu, Ben-Jin & Morse, John C., 2020, Interesting new Chinese species of Leptoceridae and Odontoceridae (Insecta: Trichoptera) from several recent collecting efforts, Zootaxa 4732 (1), pp. 138-160 : 140-142

Ceraclea (Ceraclea) megalophyllon sp. n. Yang & Morse

( Figs. 1 A–1D, 4A–4C)

Diagnosis. The male adult of this new species somewhat resembles that of Ceraclea (C.) nigronervosa (Retzius, 1783) which is widely distributed in the Palearctic and Nearctic Biogeographic Regions. Both species possess a large, hood-like tergum X, especially with the caudal portion divided into three lobes, of which the large mesal lobe is much longer than the lateral lobes. The general shape of the inferior appendages and the phallus are also of a similar pattern. It differs from that of C. nigronervosa by the following characters: (1) tergum X is extremely broad, with its median caudal lobe slightly longer than, and 1.5 times as broad as its lateral caudal lobes and all three lobes are visible in dorsal view (the median caudal lobe is much longer than the lateral caudal lobes and the lateral lobes are visible only in lateral view in C. nigronervosa ); (2) the basoventral lobe of each inferior appendage is short, stub-like and has two short, stout setae apically (this lobe is represented as a blunt triangular projection in lateral view and without stout setae apically in C. nigronervosa ,). The broad median caudal lobe of male tergum X of this new species is unique among all presently known species in subgenus Ceraclea .

The female of the new species is also similar to that of C. nigronervosa by lamallae having distinctive membranous regions at the bases of the lamellae, internal gonopod VIII (i.gon.VIII) composed of a broad semicircular lobe apicoventrally and a small tongue-shaped lobe apicodorsally. However, it can be distinguished from that of C. nigronervosa by the following characters: (1) the pair of gonopod plates (e.gon.VIII + e.gon.IX) are closely approximate on the meson anteriorly and divergent posteriorly, forming two sub-truncate lobes (the pair of gonopod plates are distantly situated, each forming an elliptical lobe in C. nigronervosa ), (2) the internal gonopod VIII is semicircular apicoventrally, much broader than the paired gonopod plates, with apex extending far beyond the tips of the gonopod plates (the internal gonopod VIII is almost identical with the paired gonopod plates in shape and with its apex scarcely surpassing the tips of the gonopod plates in C. nigronervosa ).

Adult. Length of each male forewing 8.7 mm (n = 1), of each female forewing 8.0 mm (n = 1). Type specimens preserved in alcohol for 7 years such that the color is faded and the wing and body hairs lacking. Head, basal two segments of antennae, and thorax generally brown.Wings brown, covered with fine light brown hair, wing venation of male and female typical for genus (e.g., Morse 1975, figs. 27, 28).

Male genitalia. Preanal appendages broadly oval, not fused with each other basally, widely divergent in dorsal view ( Fig. 1B ), elongate-triangular lateral and dorsal views ( Figs. 1A, 1B ). Tergum X large, hood-like with caudal portion strongly upturned ( Fig. 1A ) and divided into three large lobes, median caudal lobe about as long as and 1.5 times as broad as lateral caudal lobes in dorsal view ( Fig. 1B ). Basoventral lobe of each inferior appendage short, stub-like, truncate at apex, with two short stout setae apically ( Figs. 1A arrow, 1C arrow); main body of inferior appendage erect in lateral view; phallic guide with blunt right angle near base, setose; harpago at least 3/4 as long as subapicodorsal lobe, with triangular apex directed mesad in caudal view ( Fig. 1C ). Phallobase projecting both dorsally and ventrally with dorsal projection about 2 times as long as ventral projection, 2 long paramere spines slender and nearly straight ( Fig. 1D ).

Female genitalia. Segment IX with anterodorsal region (IXa) ending posteriorly in small, paired papillae, mostly fused with each other mesally; preanal appendages (IXb) transverse, setose bands, and separated mesally by papillae at apex of IXa ( Fig. 4B ); IXc forming transverse plate ( Figs. 4A, 4B ) with shallow apical incision in dorsal view; lamellae (IXd) short sclerotized lobes each with posteroventral margin nearly straight, shallowly excised at 1/3 distance from tip in lateral view ( Fig. 4A ); membranous regions at bases of lamellae distinctive. Pair of deep concavities (“longitudinal grooves” of Carnagey & Morse 2006) on either side of conical genitalia just above gonopod plates ( Fig. 4A arrow), visible also in dorsal and ventral views ( Figs. 4B arrow, 4C arrow). Pair of gonopod plates (e.gon.VIII + e.gon.IX) closely approximate or fused on meson anteriorly, without intervening median plate, abruptly divergent and forming two broadly sub-truncate lobes beyond middle ( Fig. 4C ); dorsal internal gonopod IX (d.i.gon.IX) large, highly scletotized and with deep V-shaped apicomesal excision in dorsal view ( Fig. 4B ); internal

gonopod VIII (i.gon.VIII) composed of broad semicircular lobe apicoventrally and small tongue shaped lobe apicodorsally ( Fig. 4C ). Spermathecal sclerite nearly circular, chufa-tuber-shaped, about as wide as long ( Fig. 4C ).

Holotype male. PR CHINA: Guang-xi Province : Xi-ning City, Wu-ming District, Da-Ming-shan [Mt.], N23.4964, E108.4401, alt. 1254 m, 21–27 May 2011, Coll. Zhou S-y . Paratypes. Same data as holotype, 1 female.

Etymology. Greek, megalophyllon , neuter noun in apposition, meaning “large leaf,” referring to the distinctively large median caudal lobe of tergum X.

Distribution. East Palearctic Biogeographic Region, southeastern China.

Figures

FIGURE 1. Ceraclea (C.) megalophyllon Yang & Morse, sp. n., male genitalia. 1A, left lateral; 1B, dorsal; 1C, ventral; 1D, phallus, left lateral.

FIGURE 4. Ceraclea spp. n., female genitalia. 4A–4C, Ceraclea (C.) megalophyllon Yang & Morse, sp. n.: 4A, left lateral; 4B, dorsal; 4C, ventral. 4D–4F, Ceraclea (Athripsodina) lamellata Yang & Hu, sp. n.: 4D, left lateral; 4E, dorsal; 4F, ventral.