Paracloeodes aristotelesi, Cruz & Salles & Hamada, 2018

Cruz, Paulo Vilela, Salles, Frederico Falcão & Hamada, Neusa, 2018, Contribution to the taxonomy of Paracloeode s Day 1955 (Ephemeroptera: Baetidae) from South America, Zootaxa 4403 (1), pp. 1-49 : 2-6

Paracloeodes aristotelesi sp. n.

( Figures 1–3 )

Diagnosis. Mature nymph. 1) frons elevated, forming one keel ( Fig. 1B ); 2) distolateral margin of labrum with pectinate and stout setae ( Fig. 2B ); 3) right mandible incisors partially fused ( Fig. 2D ); 4) distomedial projection of labial palp 1.75× width of segment III ( Fig. 2G ); 5) hind wing pads absent; 6) anterior surface of forefemur without setae near dorsal margin ( Fig. 3A ); 7) anterior surface of tibia with few stout setae ( Fig. 3A ); 8) anterior surface of tarsus without setae ( Fig. 3A ); 9) ventral margin of tarsus with one row of pectinate and stout setae ( Fig. 3A ); 10) tarsal claw 0.5× length of tarsus; 11) cercus with lateral spines ( Fig. 3E ); 12) paracercus without spines ( Fig. 3F ); 13) body color pattern as in figures 1A–D.

Description. Mature nymph. Length of body: 2.25 mm; cercus: 1.1 mm; paracercus: 1.21 mm (n=2). Head light brown. Antenna whitish. Turbinate portion of male compound eyes reddish. Frons elevated, forming keel. Antenna with scape and pedicel subcylindrical; flagellum ( Fig. 2A ) with blunt spines and thin and simple setae on apex of each segment. Labrum ( Fig. 2B ) rectangular, broader than long; length about 1.2× maximum width; dorsally with thin and simple setae scattered over surface; subapical pair of setae near middle present, distinguishable from others; near distolateral margin with two long and thin setae indistinguishable from others; ventrally with submarginal row of setae composed of bifid and pectinate setae on distal margin; pectinate and stout setae on distolateral margin; and stout setae on lateral margin; ventral surface with short and stout setae near lateral and distolateral margin. Right mandible ( Fig. 2D ) with incisors partially fused. Inner and outer set of incisors respectively with 3 + 4 denticles. Prostheca slender, bifurcated at middle, inner lobe longer than outer, both pectinate. Margin between prostheca and mola slightly convex; tuft of setae at apex of mola present, reduced to a single seta. Lateral margins slightly convex. Left mandible ( Fig. 2C ) with incisors partially fused. Inner and outer set of incisors respectively with 3 + 5 denticles. Prostheca robust, apex with three small digitiform projections. Margin between prostheca and mola straight; subtriangular process wide; tuft of setae at apex of mola present, reduced to a single seta. Lateral margin slightly convex. Hypopharynx ( Fig. 3E ) with lingua shorter than superlingua; distal margin convex; medial tuft of setae present. Superlingua rounded; thin and simple setae scattered over distal margin; lateral margin with short spines. Maxilla ( Fig. 2F ) medially, on inner margin, with 1 stout setae. Maxillary palp long, 1.8× length of galea-lacinia; setae on maxillary palp thin and simple; palp segment II 1.2× length of segment I. Labium ( Fig. 2G ) with glossa slightly narrowing toward apex, 0.9× length of paraglossa; inner margin ventrally bare; inner margin, dorsally, with nine stout setae increasing in length apically; apex with two stout setae dorsally; outer margin bare ventrally; outer margin with five stout setae dorsally; dorsal surface bare; ventral surface scattered with long and thin setae; apex with one tuft of slender setae. Paraglossa with rounded apex, bare ventrally; dorsally with three long stout setae; apical half of outer margin with one row of five long stout setae ventrally; outer margin, dorsally, with row of 10 long stout setae; dorsal surface with one row of longitudinal row of setae; ventral surface with one row of five setae increasing length near inner margin. Labial palp with segment I 0.75× length of segments II and III combined; segment I with thin and simple setae. Distomedial protuberance of segment II 1.75× width of base of segment III; inner margin covered with short and simple setae; outer margin covered with short and simple setae. Inner margin of segment III with one row of stout setae ventrally and dorsally, length 0.75× width; covered with short and simple setae. Thorax with pronotum, mesonotum and metanotum dark brown or black, basal third of fore and hind wing pads dark brown or black. Hind wing pads absent. Foreleg ( Fig. 3A ) light brown. Ratio of foreleg 1.4:(0.26mm):0.7:0.4. Forefemur with length about 3.0× maximum width; dorsal margin with row of concave stout setae; ventral margin with few short simple setae, length of setae about 0.25× maximum width of femur; anterior surface with one row of robust setae near ventral margin; posterior surface with few, long, thin and simple setae. Dorsal margin of foretibia with short and simple setae; ventral margin one row of stout setae; anterior surface with few stout setae, apex with two pectinate stout setae. Dorsal margin of foretarsus with scarce short and simple setae; ventral margin with one row of pectinate stout setae; tarsal claw 0.5× length of tarsus. Mid and hind legs similar to foreleg. Abdomen ( Figs 1A–D ) of male with terga I–V and VIII–X whitish, segments VI and VII black. Female with terga II–VII light brown, with two medial marks on anterior margin, segments VI and VII dark brown; sterna I–VII dark brown, covered with white spots and with two whitish marks near anterior margin. Gills ( Fig. 3C ) hyaline; margin with narrow spines intercalating short, thin and simple setae. Tracheae restricted to base of main trunk. Gill I subequal in length to segment II; lanceolate. Gill IV as long as length of segment V to half VI combined; lanceolated. Gill VII as long as length of segment VIII and half of IX; lanceolate. Paraproct ( Fig. 3D ) with 6–12 marginal spines; surface with micropores and short, thin and simple setae; postero-lateral extension with marginal spines. Caudal filaments white. Paracercus ( Fig. 3F ) without spines. Cercus ( Fig. 3E ) with lateral spines.

Etymology. The name of this species is an arbitrary combination of letters honoring Aristotle, the Greek philosopher, who recorded an early notice of the order Ephemeroptera .

Comments. The nymphs of P. aristotelesi sp. n. and P. atroari are similar, but they can be distinguished by the incisors of the right mandible, partially fused in P. aristotelesi sp. n. and cleft in P. atroari ; by a tuft of stout setae on the ventral surface of the glossa, present in P. aristotelesi sp. n. and absent in P. atroari ; and the length of the maxillary palp, 2.2× the length of galea-lacinia in P. atroari and 1.8× in P. aristotelesi sp. n.

Nymphs are restricted to small gravel on a sandy bottom with some leaves, always in moderate flow.

Material examined. Holotype: nymph, Brazil, Amazonas state, Presidente Figueiredo, AM 240, Km 61,5, gravel, 22.i.2009, 01°59’32.7”S / 59°31’20.1”W, F.F. Salles and P.V. Cruz cols., INPA . Paratypes: Five nymphs (two mounted on slides) 22.i.2009, F.F. Salles and P.V. Cruz cols., one in CZNC and four in INPA; two nymphs (one mounted on slides), Brazil, Amazonas state, Manaus, Reserva Florestal Ducke , igarapé Barro Branco , 21.i.2010, 02° 55’46.7”S / 59° 58’22.0”W, F.F. Salles col., INPA .

Figures

FIGURE 2. Paracloeodes aristotelesi sp. n. Nymph. A. antenna; B. labrum (left v.v., right d.v.); C. left mandible; D. right mandible; E.hypopharynx;F.maxilla; G.labium (left v.v, right d.v.).

FIGURE 3. Paracloeodes aristotelesi sp. n. Nymph. A. foreleg; B. posterior margin of abdominal tergum IV; C. gill IV; D. paraproct; E. cercus; F.paracercus.

FIGURE1. Paracloeodes aristotelesi sp. n. Nymph.A.dorsal view of male nymph; B. ventral view of male nymph; C. dorsal view of female nymph; D. ventral view of female nymph.