Corinnella lourii, Cabette, 2017

Cabette, H. R. S., 2017, Corinnella lourii, a rare new species of Baetidae (Ephemeroptera) from central Brazil, Zootaxa 4329 (2), pp. 183-188 : 184-188

publication ID	https://doi.org/ 10.11646/zootaxa.4329.2.5
publication LSID	lsid:zoobank.org:pub:56410D97-13Af-43B3-A78B-E93C5B1Ba6E6
DOI	https://doi.org/10.5281/zenodo.6035654
persistent identifier	https://treatment.plazi.org/id/039C197F-5B41-FF9E-FF70-FF36822AFDC9
treatment provided by	Plazi
scientific name	Corinnella lourii
status	sp. nov.

Treatment

Corinnella lourii sp. nov.

( Figs. 1–3 View FIGURE 1 View FIGURE 2 View FIGURE 3 )

Diagnosis. 1) Distomedial emargination of labrum broad and with three small notches ( Fig. 2a View FIGURE 2 ); 2) maxillary palp 2.0× length of galea-lacinia ( Fig. 2e View FIGURE 2 ); 3) posterior margin of terga I–IX with pointed spaced spines (as in Fig. 3c View FIGURE 3 ); 4) claws with four denticles ( Fig. 3b View FIGURE 3 ).

Description. Nymph. Length: 5.2 mm; length of antennae: 2.0 mm; length of cerci: 2.1 mm; length of terminal filament: 1.7mm; tibia I: 0.8 mm; tibia II: 0.9 mm; tibia III: 0.8 mm. General coloration: dark gray with white spots.

Head ( Figs. 1a, 1b View FIGURE 1 ). Dark gray, except on inner margin of compound eye and below median ocellus. Antennae white, with scape gray and pedicel and basal ⅓ of flagellum light gray. Lateral branch of epicranial suture slightly sinuous.

Labrum ( Fig. 2a View FIGURE 2 ). Subrectangular, broader than long. Length about 0.55× maximum width. Distal margin with broad medial emargination and three small notches. Apical ½ of lateral margin and distal margin with rows of robust, short setae, those of distal margin bifid; medial excavation with few simple, fine, short setae. Dorsal surface with three simple setae.

Left mandible ( Figs. 2b, 2c View FIGURE 2 ). Incisors strongly fused, curved inward, with six to seven denticles. Prostheca robust, apically denticulate. Margin between prostheca and mola straight without row of setae. Mola strongly modified, reduced and with few robust denticles; subtriangular process long, almost as long as incisors.

Right mandible ( Fig. 2d View FIGURE 2 ). Incisors strongly fused, curved inward, with eleven denticles. Prostheca relatively narrow (in comparison with left one), apically denticulate; margin between prostheca and mola without setae. Mola strongly modified, reduced and with crown of denticles, median denticle large (similar to subtriangular process of left mandible).

Maxilla ( Fig. 2e View FIGURE 2 ). Crown of galea-lacinia with three canines; inner ventral row with 4 to 5 setae; inner dorsal row with proximal dentisetae at same orientation of canines, other dentisetae apically denticulate. Medial protuberance of galea with 1 + 2 fine, simple setae. Maxillary palp bifid, apex of segment I with papiliform projection 0.8× length of segment I; segment II 1.2× length of segment I; maxillary palp 2.0× length of galealacinia.

Hypopharynx ( Fig. 2f View FIGURE 2 ). Lingua longer than superlingua, apex broadly rounded, with tuft of short, fine, simple setae. Superlingua with inner margin concave, with fine, simple setae on distal margin.

Labium ( Fig. 2g View FIGURE 2 ). Glossa narrow, 0.75× width of paraglossa; shorter than paraglossa, 0.8× its length; inner margin bare, apex with four long, setae; outer margin bare. Paraglossa with outer margin curved inward, inner margin straight; apex with 8 long setae. Labial palp with segment I robust, medially protruded. Segment II with robust and rounded distomedial protuberance; outer margin with many long, fine setae. Segment III conical, short, length 0.6× width, scattered with fine, simple setae.

Thorax ( Figs. 1c, 1d View FIGURE 1 ). Dark gray with marks. Coxa and trochanter gray, femora gray except for basal and apical white spots, apical ⅓ washed with red, base of tibia gray, remainder of tibia and tarsi white. Hind wing pad present. Foreleg ( Figs. 3a, 3b View FIGURE 3 ). Femur. Length about 4.2× maximum width; dorsally with row of ca. 30 spine-like setae; setae on basal 2/3 predominantly long, setae on apical ¼ predominantly short (except for most distal setae); anterior surface and ventral margin bare. Tibia. 0.85× length of femur; dorsally with ca. 12 short, spine-like setae; ventrally with ca. 14 short, spine-like setae, setae on apex 3× longer; anterior surface with row of short, spine-like setae near patella-tibial suture; patella-tibial suture present, 0.25× in length of tibia. Tarsi. 0.35× length of femur; dorsally bare; ventrally with six short, spine-like setae. Claws ( Fig. 3b View FIGURE 3 ) with four denticles, outer denticle distinctly longer than others.

Mid and hind legs. Similar to foreleg, except that setae on dorsal margin of mid femur less numerous and predominantly short on basal ¾ and long on apical ⅓, and setae on hind femur also less numerous and predominantly long medially.

Abdomen ( Figs. 1c, 1d View FIGURE 1 ). Dorsal surface dark gray except for white spots on median region of tergum I, IV, V and VIII and sublateral on terga I to VIII. Median spot on tergum V and sublateral spots on terga IV and VII wider. Marks on tergum VIII meeting subdistally. Tergum IX completely dark gray. Tergum X white, except for distomedial dark gray mark. Posterior margins of terga I–IX with pointed, spaced spines. Gills: basal ½ of outer margin gray, ¾ of inner margin dark black, main trunk of trachea of gills II to VI poorly pigmented. Gills I and VII reaching posterior margins of segments II and VIII, respectively; gills II–VI reaching apical ¼ of subsequent segments. Margins with narrow spines interspersed with short, fine, simple setae. Paraproct ( Fig. 3d View FIGURE 3 ). With three spines near inner margin; surface bare, without shagreen area; postero-lateral extension smooth. Basal ½ of caudal filaments gray, remainder white. Primary swimming setae present; outer margin of cerci with short, fine spine-like setae in each segment.

Alate stages. Unknown.

Variations. The body color pattern of the paratypes (two younger nymphs) is paler than the holotype. The unpigmented areas on abdominal terga I, IV, V, VII and VIII are much more extensive. The sublateral white spots, conspicuous on segments I–VIII on the holotype, are restricted to segments III–V.

Etymology. We are honored in naming this species after our friend Lourivaldo A. Castro, Universidade do Estado de Mato Grosso, in recognition of his extensive support for our field trips in Eastern Mato Grosso.

Distribution. BRAZIL: Mato Grosso.

Material examined. Holotype: Late instar female nymph (on a single slide), BRAZIL, Mato Grosso, Nova Xavantina , Rio Pindaíba , 14°24'30"S / 51°42'28"W, 16.iv.2016, Salles F., Victoriano A., Roges P., Cabette H. cols. ( CZNC) GoogleMaps . Paratypes: Two earlier instar nymphs, same data as holotype ( INPA) GoogleMaps .

Comments. Among the species of the genus Corinnella , C. lourii sp. nov. is closely related to C. eximia . Nymphs of both species present the labrum with a broad distomedial emargination, posterior margin of terga with pointed spines and similar abdominal color pattern (with dorsal white spots). Unlike C. thomasi , whose tarsal claws present two opposed large denticles, a single large denticle is present in C. lourii sp. nov. and C. eximia . This denticle, in fact, probably represents the apex of the tarsal claw.The presence of small notches on the distomedial emargination of labrum, the rounded apex of hypopharynx, the narrower and longer maxillary palp segment I, the reddish marks on the apex of the femora, and the overall blackish coloration, are enough to distinguish C. lourii sp. nov. from C. eximia .