Paracloeodes eurybranchus Lugo-Ortiz & McCafferty, 1996

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 : 16-19

Paracloeodes eurybranchus Lugo-Ortiz & McCafferty

( Figures 10–11 )

Paracloeodes eurybranchus Lugo-Ortiz & McCafferty 1996: 166 ; Domínguez et al. 2006: 170; Nieto & Sales 2006: 10.

Diagnosis. Nymph. 1) frons with two keels ( Fig. 11D ); 2) distolateral margin of labrum with bifid setae ( Fig. 10A ); 3) right mandible incisors cleft ( Fig. 10B ); 4) labium with segment II of palp distomedial projection 1.8× width of segment III ( Fig. 10F ); 5) hind wing pads present; 6) anterior surface of forefemur with one row of blunt setae near dorsal margin, and one row of stout setae near ventral margin ( Fig. 11A ); 7) anterior surface of foretibia with setae ( Fig. 11A ); 8) anterior margin of foretarsus without setae ( Fig. 11A ); 9) ventral margin of foretarsus with one row of stout setae ( Fig. 11A ); 10) tarsal claw 0.48× length of tarsus ( Fig. 11A ); 11) cercus with long spines every two segment; 12) paracercus with short spines on each segment.

Redescription. Nymph. Head. Frons with two keels. Antenna with scape and pedicel subcylindrical; flagellum with blunt spines and thin and simple setae on apex of each segment. Labrum ( Fig. 10A ) rectangular, broader than long; length about 0.7× maximum width; dorsally with thin and simple setae scattered over surface; subapical pair of setae near middle distinguishable from others; near anterolateral margin with two long setae distinguishable from others; ventrally with submarginal row of setae composed of bifid setae on distal and distolateral margin. Right mandible ( Fig. 10B ) incisors cleft. Inner and outer set of incisors respectively with 3 + 4 denticles. Prostheca slender, bifurcated at middle, inner lobe longer than outer. Margin between prostheca and mola convex; tuft of stout setae at base of mola present; tuft of setae at apex of mola present, reduced to a single seta. Lateral margins slightly convex. Left mandible ( Fig. 10C ) with incisors partially fused. Inner and outer set of incisors respectively with 3 + 5 denticles. Prostheca robust, apex with three small digitiform projection. Margin between prostheca and mola slightly convex; tuft of stout setae at base of mola present; subtriangular process narrow, above level of area between prostheca and mola; tuft of setae at apex of mola absent. Lateral margins slightly convex. Hypopharynx ( Fig. 10E ) with lingua subequal in length to 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. 10D ) medially, on inner margin, with 1 + 2 stout setae. Maxillary palp long 1.64× length of galea-lacinia. Labium ( Fig. 10F ) with glossa 0.9× length of paraglossa; inner margin bare ventrally; inner margin, dorsally, with 11 stout setae increasing in length apically; apex, dorsally, with three robust setae; outer margin ventrally bare, outer margin dorsally with eleven long stout setae increasing in length distally; dorsal surface bare; ventral surface scattered with short, thin and simple setae. Paraglossa with one row of long and stout setae on outer margin; dorsal surface with two longitudinal rows of stout setae, one near outer margin and other near inner margin; ventral surface with one row of five stout setae near inner margin. Labial palp with segment I 0.89× length of segments II and III combined; segment I with thin and simple setae. Segment II with medial protuberance 1.8× width of base of segment III; outer margin with many, long and simple setae. Segment III inner margin with one row of stout setae dorsally; length 1.13× width; outer margin with short and thin setae. Thorax yellowish. Hind wing pads present. Foreleg ( Fig. 11A ) ratio 1.5:(1):1:0.47. Forefemur with length about 3.15× maximum width; dorsal margin with row of blunt setae (in lateral view they look like stout setae); ventral margin with one row of stout setae; length of setae on dorsal margin about 0.1× maximum width of femur; anterior surface with two rows of robust and blunt setae near dorsal margin, and one row of robust and stout setae near ventral margin. Ventral margin of tibia with one row of robust and stout setae; anterior surface with robust and stout setae. Dorsal margin of tarsus with scarce short and simple setae; anterior surface without stout setae; ventral margin with one row of stout setae; tarsal claw 0.48× length of tarsus. Abdomen yellowish. Gills ( Figs 11B, 11C and 11E ) margin with narrow spines intercalating short, thin and simple setae. Tracheae pigmented, restricted to main trunk. Gill I as long as length of segment II and half of III combined; lanceolate. Gill IV as long as length of segments IV and V combined; oval. Gill VII as long as length of segments VIII and IX combined. Paraproct with 21 marginal spines; postero-lateral extension with marginal spines. Paracercus with short spines on each segment. Cercus with spines on all segment, long spines every two segment.

Comments. The male subimago, inside the nymphal exuvia, has a subgenital plate with a medial spine.

Paracloeodes eurybranchus and P. leptobranchus are very similar, and this has generated doubts about the validity of the latter species ( Nieto & Salles 2006). The morphological study of types corroborated both species as valid. They can be distinguished by segment II of the labial palps with the distomedial projection 2.1× width of segment III, anterior surface of forefemur with one row of strong pectinate and stout setae near the ventral margin, the ventral margin of the foretarsus with one row of pectinate and stout setae, and the tarsal claw 0.56× length of the tarsus in P. leptobranchus . In contrast, P. eurybranchus has segment II of the labial palp with a distomedial projection 1.8× the width of segment III, the anterior surface of the forefemur with one row of stout setae near the ventral margin, the ventral margin of the foretarsus with one row of stout setae, and a tarsal claw with length 0.48× the length of the tarsus.

Traditionally, the shape of gills has been used to differentiate both species, hence their names. Our morphological study corroborated the original argumentation of their gills having the same general shapes, except that the gills of P. eurybranchus ( Fig. 11B ) are broader than the gills of P. leptobranchus ( Fig. 17C ).

Material Examined. One nymph exuvia on slide (holotype), ARGENTINA, Córdoba Province, Río Pocho, ca 25 Km WSW of Sansacate , 1100m, IV-15/17 - 1967, L. Peña, PERC. One nymph (paratype), ARGENTINA, Córdoba Province, Los Cóndores, ca 25 Km NE of Vila Cura Brochero , 14.iv.1967, L . Peña, PERC. Four nymphs, ARGENTINA, Córdoba, Río Nono, 5 Km de Mina Clavero, S 31°48’16’’/ W65°00’14’’, 840 m, 14–15.xi.2001, C . Nieto & Orce cols., INPA.

Figures

FIGURE 10. Paracloeodes eurybranchus. Nymph. A. labrum (left v.v, right d.v.); B. right mandible; C. left mandible; D. maxilla; E. hypopharynx; F. labium (left v.v, right d.v.).

FIGURE 11. Paracloeodes eurybranchus. Nymph. A. foreleg; B. gill IV; C. dorsal view; D. frontal view of head; E. detail of gill.

FIGURE 17. Paracloeodes leptobranchus.Nymphs.A. foreleg; B. dorsal view of nymph; C. gill IV.