Chimarra (Chimarrita) mesodonta Vilarino & Calor

Vilarino, Albane & Calor, Adolfo Ricardo, 2015, New species and records of Chimarra (Trichoptera, Philopotamidae) from Northeastern Brazil, and an updated key to subgenus Chimarra (Chimarrita), ZooKeys 491, pp. 119-142 : 123

Taxon classification Animalia Trichoptera Philopotamidae

Chimarra (Chimarrita) mesodonta Vilarino & Calor sp. n. Figs 2 A–G, 3 A–B

Diagnosis.

According to the phylogenetic analysis, Chimarra mesodonta has a sister relationship with the clade ( Chimarra chela ( Chimarra pusilla , Chimarra forcipata )) based on the presence of short phallic spines with a pronounced helical twist, but differs from these species by not sharing the flattened and button like preanal appendages. Among the species contained in this clade, this new species most closely resembles Chimarra forcipata by the overall aspect mainly in lateral view, and by both possess a mesally a mesally directed acute projection on the inferior appendage. Chimarra mesodonta can be distinguished from Chimarra forcipata by the following characters: R1 of the hind wing is not fused to the subcosta (fused in Chimarra forcipata ); tergum X is shorter, and in lateral view slightly longer than the dorsal portion of segment IX (nearly 2 × longer than segment IX in Chimarra forcipata ); preanal appendage is not flattened (flattened in Chimarra forcipata ); the ventral process is not strongly tapered, having apex subacute to truncate (strongly tapered and acute in Chimarra forcipata ); in ventral view the apex of inferior appendage is broad and a projection is formed in the medial margin (apex strongly narrowed and with the projection formed apically in Chimarra forcipata ); and the phallus bears 2 large helically curved spines (several small spines in Chimarra forcipata ).

Description.

Adult. Forewing length 3.2-3.7 mm (males, n=5), 3.4-3.9 mm (females, n=6). Overall color (in alcohol) light brown. Forewing venation typical for Chimarra ; Rs straight s, r, r-m and m of forewing unpigmented and linearly arranged, m-cu and apex of Cu2 also unpigmented; 2A apparently forked to 1A and 3A. Hind wing, R1 not fused to Sc; Rs 4-branched; M 3-branched. Posterior setal head warts large, triangular, meeting broadly on medial portion. Second segment of maxillary palp shorter than 3rd segment. Male pretarsal claws symmetrical, unmodified.

Male genitalia. Segment IX synsclerous; lateral view, anteroventral margin expanded, apex narrowed, acute; ventral process elongate, narrow, subacute, somewhat curved. Tergum X short, fused to segment IX; with short weakly sclerotized mesal lobe apically excavated, tergum X fully divided dorsally, separated ventrally until the length of mesal lobe, forming 2 separate, simple, lateral lobes with numerous sensilla. Preanal appendage very short, rounded, button-like, fused near base of tergum X. Inferior appendage short, triangular in lateral aspect; in ventral view, strongly rounded basally, tapered apically, apex rounded, medial margin forming tooth-like projection. Phallotheca tubular, slightly bent at middle, with rounded phallobase; with internal membranous structures and bearing 2 distinct curved phallic spines. Phallotremal sclerite complex could not be distinguished.

Female genitalia. Sternum VII without ventral process. Segment VIII synsclerous, triangular in lateral aspect, dorsally membranous, very reduced; lateral suture line not evident, only demarcated by difference in texture and pigmentation of ventral portion, more granulous; anteroventral margin with subacute, deflected ventral process, posteroventral margin also with short ventral process. Sternum IX elongate, lightly sclerotized basally, with elongate, narrow, paired, ventral sclerites; sternum membranous between paired sclerites, and laterally from base to apex. Tergum IX elongate, narrow, nearly straight, sparsely setose, anteroventrally with short apodeme. Segment X with elongate basal portion, furrowed dorsally, with basal and inner margins more sclerotized, apically with small setose lobes, each with apical cercus. Vaginal apparatus largely membranous, anteriorly with weakly sclerotized structure.

Holotype, male

(alcohol). BRAZIL: Bahia: Santa Teresinha, Pedra Branca, Serra da Jibóia, 12°51'016"S, 39°28'48"W, el. 679 m, 07.viii.2009, UV Light Pan trap, Calor A.R. & Lecci L.S. (MZUSP).

Paratypes.

BRAZIL: Bahia: same data as holotype, 2 males (alcohol) (UFBA); same, 12°51'00.6"S, 39°28'48.3"W, el. 678 m, 08. viii– 28.ix.2009, Malaise trap, 1 female (alcohol) (UFBA); same, 04.ii.2010, Calor A.R. & Lecci L.S., 2 males, 2 females (alcohol) (UMSP); same, 10.vii.2010, UV Light Pan trap, Calor A.R. & Lecci L.S., 1 male (alcohol) (UFBA); same, 12°51'00.6"S, 39°28'48.3"W, el. 678 m, 19.vii.2009, Calor A.R. & Lecci L.S., 3 males (alcohol) (UFBA); Varzedo, Fazenda Vão da Serra, Riacho 2, 12°50'58.4"S, 39°28'04.0"W, el. 414 m, 08.ii.2014, UV Light Pan trap, Calor A.R. & Vilarino A., 16 males, 6 females (alcohol) (UFBA).

Etymology.

The species name is derived from the Greek meso, middle, and donti, tooth, referring to the median tooth present in the inferior appendages.

Remarks.

The aperture between the lateral lobes of tergum X can be wider depending on the specimen examined. Also, membranous structures of the endotheca and the lightly sclerotized mesal lobe of tergum X vary in shape depending on the preparation. When cleared in lactic acid, the basal portion of the endotheca shows some sclerotization and may be considered a rod of the phallotremal sclerite complex. Concerning the phylogenetic relationships, the new species shares character 30(1), segment VIII of female genitalia much narrowed or obsolete dorsally, with the Chimarra rosalesi Group sensu Blahnik (1997). The shared character 7(1), phallic spines short, with pronounced helical twist, supports the clade ( Chimarra mesodonta ( Chimarra chela ( Chimarra pusilla , Chimarra forcipata ))). However, the new species does not posses character 13(1), preanal appendages flattened and button-like, a character shared by the other three species.