Leptohyphes cornutillus, Nascimento, Jeane M. C., Molineri, Carlos & Salles, Frederico F., 2014

Nascimento, Jeane M. C., Molineri, Carlos & Salles, Frederico F., 2014, Redescription of Leptohyphes cornutus Allen, 1967 (Ephemeroptera: Leptohyphidae) and description of three related new species, Zootaxa 3893 (3), pp. 397-415 : 402-408

Leptohyphes cornutillus sp. nov.

( Figs. 6–9 and 14 )

Material examined. HOLOTYPE, male mature nymph, BRAZIL, Espírito Santo, Domingos Martins, Megalcinho, 30/iii/2010, S 20˚ 15’ 0.6” / W 40˚ 43’ 26.9”, 622m, Salles FF leg. ( INPA). PARATYPE, 1 female mature nymph (parts on slide), same data as holotype ( CZNC).

Mature nymph. Length of male: body, 5.0 mm; hind femur, 1.5 mm; caudal filaments, 4.0 mm. Length of female (mm): body, 8.2 mm; hind femur, 2.0 mm; caudal filaments, 4.5 mm. General coloration brownish, almost completely shaded with black ( Figs 6 , 7 ). Head ( Fig. 7 A) with two pairs of tubercles, a submedian smaller and sublateral longer and pointed; clypeus well developed and subquadrate. Gena ( Fig. 7 A) strongly projected. Mouth parts ( Fig. 8 ). Labrum ( Fig. 8 A): with an anteromedial marked indentation on fore margin. Labium ( Fig. 8 C): submentum with pointed and projected anterolateral corner; glossae shorter than paraglossae; labial palp with basal segment three times the length of segment two, apical segment subequal in length to segment two. Hypopharynx ( Fig. 8 D): lingua with short and strong setae. Maxillae ( Fig. 8 B): maxillary palp three-segmented with setae at joints, suture on galea and lacinea complete. Mandibles ( Fig. 8 E, F): left mandible with fused and strong incisives, both mandibles with a dense row of setae on dorsolateral surface; prostheca reduced (left), or absent (right). Thorax. Pronotum subrectangular with two pairs of sublateral tubercles, a large and pointed tubercle near hind margin and a smaller blunt anterolateral tubercle. Mesonotum with three pairs of tubercles: a short sublateral pair on fore margin, a longer and acute sublateral pair at 1/3 from anterior margin and a submedian pair of tubercles at apex of wing pads. Mesonotum with blunt anterolateral projection. Hind wing pad present in both sexes, small. Thoracic sterna paler than terga. Legs: brownish yellow shaded with black, except on apex of tibia and tarsi, tarsi brownish. Fore leg ( Fig. 9 A): femur ratio length/maximum width 2.1–2.3; transversal row of seven stout spines at 1/3 from base; fore margin bare, hind margin with five stout spines (on elevated sockets) distally to transversal row; apex of femur medially and dorsally projected. Tibia subequal in length to femur with row of setae on inner margin; tarsus half the length of tibia with row of setae on inner margin, dorsum with elevated ridge; tarsal claw ( Fig. 9 C) apically curved with six marginal denticles and one subapical submarginal denticle. Middle and hind legs ( Figs. 9 B): coxae with short semicircular dorsal projection; hind femur ratio length/maximum width 2.2; with dorsally row of six blunt spines at base, fore margin bare, hind margin with ten stout spines on elevated sockets, dorsal surface with three stout spines at the middle; dorsomedial projection on apex of femur more pronounced than fore leg. Tibia 1.2x the length of femur, with dorsal ridge, inner margin with strong setae; hind margin with 2–3 strong setae basally and weaker setae distally. Tarsus 0.4x the length of femur, inner margin with setae, tarsal claw as in fore leg. Abdomen ( Fig. 7 B) with strong spines and weak setae on dorsum. Lateral margins of segments III–VI expanded forming pointed flanges; segment VII and VIII strongly expanded laterally. Terga with a pair of blunt submedian projection on hind margin. Posterolateral spines on segments V–IX (flange on IV is also somewhat pointed resembling a posterolateral spine). Abdominal sternum IX with distal V-shaped indentation (female). Gills: operculate gill on abdominal segment II yellowish translucent almost completely shaded with black on dorsum, except medially and along distal margin, ventrally with strong basal spine and two long and pointed lamellae; other gills whitish almost completely shaded with black. Gill formula 3/11/9 /9/6. Caudal filaments completely covered with blunt scattered setae, and with a whorl of strong spines at the segment joint after every fourth segment.

Adults. unknown.

Diagnosis ( Table 1 ). i) paired tubercles on head (2 pairs), pronotum (2 pairs, anterior pair very small), and mesonotum (3 pairs), abdominal terga with remnants of paired tubercles on hind margin (blunt and short undulations in dorsal view) ( Figs. 6 , 7 ); ii) fore femur length/maximum width, 2.1–2.3 ( Fig. 9 A); iii) fore margin of middle and hind femora without spines, hind margin with 5 rounded and stout spine-like setae on elevated sockets ( Figs. 9 B, C); iv) tarsal claws denticulation 6+1 ( Fig. 9 C); v) middle and hind coxa only with short semicircular projection on dorsum ( Figs. 9 B, C); vi) hind wing pads present in females; vii) gill formula 3/11/9 /9/6, gill V without ventral extension on dorsal lamella.

Etymology. From cornutus , given the similarity with L. cornutus , and the diminutive suffix ilus. An allusion to the smaller size of the tubercles of the new species.

Distribution. Brazil (Espírito Santo).

Discussion. L. cornutillus is similar to L. cornutus , but they can be differentiated by the presence of three paired tubercles on mesonotum of the first species ( L. cornutus shows two pairs), and by the absence of coxal projection in L. cornutillus (character shared with L. airuoca ) ( Table 1 ). The form of mandibles in L. cornutillus , with very short canines ( Figs. 8 E, F), somewhat resembles those of L. mandibulus Baumgardner (2007) , but this Central American species does not present tubercles on body, among other important differences. As stated by Baumgardner (2007), the short canines could be as a result of wear and tear, but we discard this probability because other mouthparts do not show any mark related with wear and tear ( Arens 1990).

Figures

FIGURE 6. Leptohyphes cornutillus, sp. nov., habitus of nymph. A) dorsal view; B) lateral view.

FIGURES 7. Leptohyphes cornutillus, sp. nov., nymph. A) head, frontal view; B) abdomen, dorsal view.

FIGURES 8. Leptohyphes cornutillus, sp. nov., nymphal mouthparts. A) labrum; B) maxilla; C) labium; D) hypopharynx; E) left mandible; F) right mandible.

FIGURES 9. Leptohyphes cornutillus, sp. nov., nymphs. A) fore leg; B) middle leg; C) anterior tarsal claw.

FIGURE 14. Map of South America showing in detail the distribution of Leptohyphes species.