Cecidonius Moreira & Goncalves

Moreira, Gilson R. P., Eltz, Rodrigo P., Pase, Ramoim B., Silva, Gabriela T., Bordignon, Sergio A. L., Mey, Wolfram & Goncalves, Gislene L., 2017, Cecidoniuspampeanus, gen. et sp. n.: an overlooked and rare, new gall-inducing micromoth associated with Schinus in southern Brazil (Lepidoptera, Cecidosidae), ZooKeys 695, pp. 37-74 : 41-42

Cecidonius Moreira & Goncalves gen. n. Figs 2, 3, 4, 5, 6, 7, 8, 9

Type species.

Cecidonius pampeanus Moreira & Gonçalves, new species

Diagnosis.

Cecidonius gen. n. bears several adult, pupal, larval, and gall features that in conjunction differentiate it from all cecidosid genera. Unlike other cecidosids, adults of Cecidonius have lateral cervical sclerites with anterior arms short and posterior ones with distal portion membranous. Females have a long ovipositor, bearing a large oviscapt cone with internal dorsal crest that extends cephalad within the seventh abdominal segment. In particular, they differ from those of the New Zealand Xanadoses that have a well-developed proboscis and five-segmented maxillary palpus ( Hoare and Dugdale 2003) by having a vestigial proboscis and two-segmented maxillary palpus, among other characters. Unlike all species of the African Scyrotis that have forewings with four radial veins ( Mey 2007), Cecidonius has five R-veins. With the exception of Oliera , which has small rudiments of galea ( Moreira et al. 2012), other South American cecidosids show no vestiges of such structures. However, adults of Cecidoniu s have moderately well-developed galea. Contrary to those of Oliera where the maxillary and labial palpi are respectively three- and two-segmented, Cecidonius has the reverse; that is, two- and three-segmented maxillary and labial palpi, respectively. The pupa of Cecidonius is unique among all described cecidosids (those of Scyrotis are unknown), by having a stout and truncate cocoon cutter, flanked at the base by a pair of small, similarly shaped processes. In addition, in Cecidonius pupae the anterior margin of abdominal terga bear strong, posteriorly directed, transversally aligned spines that are much smaller in other genera. The larva of Cecidonius is also unique in having long thoracic setae, compared to short abdominal ones. They have two pair of stemmata; there is one in Xanadoses , and they are absent in other South American genera (larvae of Scyrotis are also unknown). Their woody, cylindrical galls are also unique, initially developing within swollen stems of S. weinmannifolius in southern Brazil. Later in ontogeny, they rupture the plant stem, thus growing externally. They are dehiscent, falling to the ground where pupation occurs. Contrary to those of Scyrotis (for detail, see von Noort et al. 2007), they do not exfoliate from the stem; they detach with their proximal base open, the corresponding orifice being clogged by larval feces.

Description of adults

(Figs 2-4). Male and female similar in size and color; the body is covered with uniform, faded copper-coloured scales. Small moth, forewing length 4.16-4.58 mm (n = 4). Head (Fig. 3A): frons and vertex smooth, with sutures weakly developed; vestiture consisting of a pair of latero-dorsal scale tufts curved forward over the frons. Scales slender, lamellar, suberect and scattered over labrum, haustellum, maxillary, and labial palpi. Eyes relatively large, rounded; vertical diameter ~ 2.0x, minimum interocular distance across frons. Antennae median (~ 0.7x length of forewing); scape smooth except for medium dense pecten; flagellum filiform, with slender scales scattered only over dorsal half; ventral half with several elongate sensilla ca. 0.7 × length of flagellomere. Labrum greatly reduced. Pilifers and mandibles absent. Haustellum moderately developed (~2/3 labial palpi length). Maxillary palpi short, 2-segmented; ratios of segments from base ~1.0:1.4. Labial palpi 3-segmented, bent anteriorly and upward (~2/3 eye width in length); ratio of segments from base ~1.0:1.8:1.6. Thorax: Anterior arms of laterocervical sclerites (Fig. 3B) short; posterior arms with distal portion weakly melanised. Metafurca (Fig. 3D, E) with slender, elongate postero-dorsal apophyses, free from secondary arms; antero-dorsal apodemes present. Wings (Fig. 3C) lanceolate; microtrichia reduced in number; accessory cell present; retinaculum absent. Wing coupling consisting of ~20 frenular scales arising in two to three irregular rows near base of costa. Veins 13 in number, all reaching the margin; L/W index ~2.9; Sc ending near midpoint of wing margin, radius with 5 free branches, M 3-branched, CuA 2-branched, CuA1 and M3 well separated from each other basally, CuP faint distally and not stalked with 1A+2A. Hindwing: ~0.8 forewing in length, L/W index ~2.9; Sc and R stalked and ending distally at midpoint of wing margin, Rs unbranched, M 3-branched, M1 and M2 well separated, CuA 2-branched, CuA1 and M3 well separated, CuP faded, not stalked with 1A+2A. Legs (Fig. 3F) with spurs 0-2-4; epiphysis present. Tibial length proportion (anterior / medium / posterior legs) ~ 0.6:0.7:1.0. Abdomen: Sternum 2 with broad, U-shaped caudal rim; tergosternal connection absent. Male with remaining pre-genital segments unmodified. Female with abdominal segment A7 ~ 4x the length of A6; caudal margin bearing a dense ring of stout, elongate setae.

Male genitalia (Fig. 4A, B). Uncus moderately bilobed. Socii consisting of a pair of setigerous, dorsally directed lobes. Valva long and slender, with an elongate pectinifer along ventral margin extending ~ distal half-length of valva. Vinculum Y-shaped. Phallus (Fig. 4B) simple, slender, and tubular, rosette-like shaped anteriorly; vesica without cornuti. Juxta (Fig. 4B) elongate (~ 2/3 phallus length), slender, slightly spatulate distally and encircling phallus caudally. Saccus stout and tubular, ~ 1.3 × length of valve.

Female genitalia (Fig. 4C, D). Oviscapt cone (sensu Kristensen 2003, San Blas and Davis 2013) present, with internal dorsal crest long, reaching the anterior portion of tergum seven. Anterior apophyses long, extending beyond fifth abdominal segment. Posterior apophyses ~1.5 × length of anterior apophyses, and with anteriorly attached apodemes of similar width. Posterior apophyses are caudally fused to form an acute ovipositor, whose apex is compressed and sagittate, the lateral ridge bearing minute serrations. A typical primitive monotrysian reproductive system, with cloaca and vestibulum each bearing a pair of slender apodemes that extend anteriorly within abdominal segment 7; vestibulum without sclerotized structures; ductus and corpus bursae membranous, the latter saculiform, without signum; spermatheca connected to small, saculiform utriculus by a slightly coiled, afferent canal.

Etymology.

The genus name is derived from a composition between the Portuguese Cecidia (a gall; from the Greek, kekídion) with Don (an English nickname). Thus, the generic name means “Don`s gall", named after Donald Davis from the Smithsonian Institution, USA, in recognition of his great contribution to the development of world lepidopterology, and in particular for having kindly introduced the first author to the study of Neotropical cecidosids a few years ago. The name is to be treated as masculine.