Paracloeodes lotor, Cruz, Paulo Vilela, Usher, Andrew K. & Jacobus, Luke M., 2017

Cruz, Paulo Vilela, Usher, Andrew K. & Jacobus, Luke M., 2017, Review of continental North and Central American Paracloeodes Day 1955 (Ephemeroptera: Baetidae), including description of a new species from Minnesota, U. S. A., Zootaxa 4263 (2), pp. 333-346 : 339-343

Paracloeodes lotor n. sp.

Diagnoses. Male imago. 1) forewing with divergent marginal intercalary veins ( Fig. 28 ); 2) hind wing absent; 3) posterior margin of styliger plate concave ( Fig. 29 ); 4) posterior margin of styliger plate with pointed spine ( Fig. 29 ).

Mature nymph. 1) frons with two convergent keels, fused near clypeus ( Fig. 11 ); 2) labrum with a pair of subapical setae near the middle that are distinguishable from others dorsal setae ( Fig. 33 ); 3) one row of five simple setae near distolateral margin of labrum ( Fig. 30 ); 4) distal margin of labrum with bifid setae ( Fig. 30 ); 5) distolateral margin of labrum with bifid and strongly pectinate setae ( Fig. 30 ); 6) right mandible incisors cleft ( Fig. 32 ); 7) outer incisor of right mandible with one vestigial denticle ( Fig. 32 ); 8) maxillary palp 1.60× the length of galea-lacinia ( Fig. 33 ); 9) apical half of paraglossa with an abrupt decrease in width (subtriangular condition) ( Figs. 20, 23 , 34 ); 10)angle between inner margin of labial palp segment III and distal margin of segment II greater than 90°; 11) lobe of labial palp segment II relatively angulate ( Fig. 34 ); 12) base of labial palp segment III 0.4× the width of labial palp segment II ( Fig. 34 ); 13) labial palp with length of segment III 0.70× the width of its base ( Fig. 34 ); 14) hind wing pads absent; 15) anterior surface of forefemur with one row of small blunt setae near dorsal margin ( Fig. 35 ); 16) medial row of setae on anterior surface of forefemur present ( Fig. 35 ); 17) anterior surface of forefemur without row of blunt setae near the ventral margin ( Fig. 35 ); 18) fore tarsal claw 0.56× the length of the tarsus, with minute denticles ( Fig. 35 ); 19) abdominal color pattern as in Figures 5–8 ; 20) length of gills less than 2.0× the length of the subsequent abdominal segment ( Fig. 7 ).

Description. Male imago. Body lost. Thorax. Wings ( Fig. 28 ). Forewing hyaline, veins light brown; stigmatic area with seven cross veins touching subcostal vein; marginal intercalary veins paired and divergent, except veins between CuP and A. Abdomen. Genitalia ( Fig. 29 ). Unistyliger cylindrical; forceps segment III elongate and oval. Posterior margin of styliger plate concave with pointed spine medially.

Mature nymph. Length of body: 3 mm; cercus: 1.5 mm. Head. Coloration: yellowish. Frons with two convergent keels, fused near clypeus ( Fig. 11 ). Labrum ( Fig. 30 ). Rectangular, broader than long; length 0.6× maximum width. Dorsally with fine and simple setae scattered over surface; subapical pair of setae, near middle, distinguishable from others; near distolateral margin with one row of five, long and simple setae. Ventrally with submarginal row of setae composed of robust and bifid setae on distal margin, and bifid and strong pectinate setae on distolateral and lateral margins. Left mandible ( Fig. 31 ). Incisors partially fused. Inner and outer sets of incisors with 3 + 4 denticles, respectively. Prostheca robust, apex with two small projections. Margin between prostheca and mola slightly convex; tuft of spine-like setae present at base of mola; tuft of setae present at apex of mola. Hypopharynx (damaged). Lingua subequal in length to superlingua, distal margin convex; medial tuft of setae absent. Superlingua rounded; fine, simple setae scattered over distal margin; lateral margin with short spines. Right mandible ( Fig. 32 ). Incisors cleft. Inner and outer set of incisors with 2 + 3 denticles, respectively; outer margin of outer incisor with one vestigial denticle. Prostheca slender, bifurcate at middle, inner lobe longer than outer lobe. Tuft of spine-like setae present at base of mola; single seta present at apex of mola. Lateral margins slightly convex. Maxilla ( Fig. 33 ). Maxillary palp 1.6× length of galea-lacinia; setae on maxillary palp fine and simple. Labium ( Fig. 34 ). Glossa with apical decrease in width (subtriangular condition), 0.9× length of paraglossa. Inner margin, dorsally, with seven spine-like setae and apex with three robust spine-like setae. Outer margin with seven long spine-like setae dorsally. Dorsal surface bare. Ventral surface scattered with short, fine, simple setae. Paraglossa. Apical half with abrupt decrease in width (subtriangular condition); outer margin with one row of long spine-like setae dorsally; dorsal surface with two longitudinal rows of setae, one near outer margin and other near inner margin; ventral surface with one row of five spine-like setae near inner margin. Labial palp with segment I 0.83× combined length of segments II + III. Inner margin of segment II with few short and simple setae; angle between inner margin of labial palp segment III and distal margin of segment II greater than 90°; outer margin with many long and simple setae; dorsally covered with simple setae. Inner margin of segment III with one row of spinelike setae ventrally and dorsally; base of segment III 0.4× total width of segment II; length of segment III 0.7× width. Thorax ( Fig. 8 ). Light brown with black or dark brown spots. Hind wing pads absent, but nipple-like projection present. Foreleg ( Fig. 35 ). Dorsal margin of forefemur with row of blunt setae ( Fig. 36 ). Ventral margin with few short and simple setae. Length of setae about 0.1× maximum width of femur; anterior surface with one row of minute and blunt setae near dorsal margin and one row of robust and blunt setae at middle. Tibia. Ventral margin with one row of robust spine-like setae. Tarsus. Dorsal margin with short and simple setae; ventral margin with one row of spine-like setae. Claw 0.56× length of tarsus, with two rows of minute denticles ( Fig. 37 ). Mid- and hindlegs similar to foreleg, except for denticles of claws being smaller. Abdomen ( Figs. 5 and 6 ). Terga II, III and IX brown; one anteromedial spot on each of terga III–X; dorsolateral Y-like marks on each of terga III, V and VI; lateral dashes on terga II–VII. Sterna with intersegmental transverse bars of pigmentation. Gills hyaline, suboval ( Fig. 39 ); margin with narrow spines intercalating short, fine and simple setae; length of gills less than 2.0× length of subsequent abdominal segment. Posterior margins of terga with triangular spines ( Fig. 38 ). Cerci ( Fig. 40 ) and terminal filament ( Fig. 41 ) mostly pale, with short spines on each segment.

Etymology. The specific epithet is a reference to the type locale—Coon Rapids—and to Procyon lotor ( Linnaeus 1758) , the northern raccoon. We suggest that this species commonly be referred to as the Coon Rapids small minnow mayfly.

Biology. The recently collected nymph was taken from sand-silt-cobble substrate in shallow water (<1 m deep) of the Mississippi River, between Coon Rapids Dam and Dunn’s Island ( Figs. 42, 43 ). Based on the different dates of collection, Paracloeodes lotor n. sp. might have multiple generations per year, or it might have asynchronous development. We note that the dam had already been in place for about 25 years prior to Richard Daggy’s original collection of this species ( Anfinson et al. 2003).

Comments. The nymph and male imago of Paracloeodes lotor n. sp. have unusual characteristics for North American species, such as the apical half of the paraglossa having an abrupt decrease in width (what we call the subtriangular condition, Figs. 20 and 23 ) in the nymphal stage and the subgenital plate having a medial spine in the male imago stage ( Fig. 20 ). These features also are present in P. charrua Emmerich & Nieto (2009) from South America, and the subgenital spine has been described for three species of Rivudiva Lugo-Ortiz & McCafferty 1998 . Similarities between Paracloeodes and Rivudiva have been indicated previously by Lima et al. (2013), but with no conclusions about phylogenetic relationships. Among Paracloeodes species, P. lotor n. sp. appears to share unique features with the three other North American species, plus P. lilliputian Kluge 1991 ( Cuba) , P. morelli Emmerich & Nieto 2009 (South America), P. pacawara Nieto & Salles 2006 (South America) and P. yuto Nieto & Salles 2006 (South America); these features include a row of simple setae on the dorsal surface of the labrum, near the distal margin, and minute foreclaw denticles that are subequal in size to each other, but that are larger than the denticles on the mid- and hind claws.

Material examined. Holotype: One set nymphal exuviae on slide, U.S.A., Minnesota, Mississippi River, Coon Rapids , 6.vi.1939, R.H. Daggy, (mounted vi.1983, R.D. Waltz), PERC 0,0 12,563. Additional material: One male imago on slide (parts), same data as holotype, except PERC 0,0 12,562. One nymph (parts on slide and in microvial) , U.S.A., Minnesota, Anoka / Hennepin Counties, Mississippi River at Coon Rapids Dam , 45.141485°N, 93.311884°W, 19.ix.2014, A.K. Usher, L.M. Jacobus [ PERC] .

Figures

FIGURES 26 – 29. Paracloeodes lotor n. sp. 26. slide of male imago (it is not a paratype designated in Daggy, 1945); 27. slide of holotype (nymph); 28. male imago forewing; 29. male imago genitalia.

FIGURES 1 – 13. Photographs of North American species. 1. Paracloeodes fleeki, dorsal view of nymph (holotype); 2. Paracloeodes lugoi, dorsal view of thorax and abdomen of nymph (paratype); 3. Paracloeodes minutus, dorsal view of male imago (paratype of P. abditus); 4. Paracloeodes minutus, dorsal view of nymph (paratype of P. abditus); 5. Paracloeodes lotor n. sp., dorsal view of abdomen; 6. Paracloeodes lotor n. sp., ventral view of abdomen; 7. Paracloeodes lotor n. sp., lateral view of body; 8. Paracloeodes lotor n. sp., dorsal view of thorax; 9. Paracloeodes fleeki, frontal view of head (holotype); 10. Paracloeodes lugoi, frontal view of head (paratype); 11. Paracloeodes lotor n. sp., frontal view of head; 12. Paracloeodes minutus, ventral view of male genitalia (P. abditus paratype); 13. Paracloeodes minutus, detail of subgenital plate (holotype of P. minutus).

FIGURES 30 – 34. Paracloeodes lotor n. sp. 30. labrum (left v. v., right d. v.); 31. left mandible; 32. right mandible; 33. maxilla; 34. labium (left d. v., right v. v.).

FIGURES 17 – 25. 17. Paracloeodes fleeki, shape of segment II and III of labial palp (paratype); 18. Paracloeodes lugoi, shape of segment II and III of labial palp (holotype), red lines demonstrate how ratios were measured; 19. Paracloeodes minutus, shape of segment II and III of labial palp (paratype of P. abditus); 20. Paracloeodes lotor n. sp., photograph, subtriangular shape of glossa and paraglossa (holotype); 21. Paracloeodes lugoi, photograph, intermediary degree of roundness on glossa and paraglossa; 22. Paracloeodes minutus, photograph, subcircular or rounded shape of glossa and paraglossa (P. abditus paratype); 23. Paracloeodes lotor n. sp., line drawing, subtriangular shape of glossa and paraglossa; 24. Paracloeodes lugoi, line drawing, intermediary degree of roundness on glossa and paraglossa; 25. Paracloeodes minutus, line drawing, subcircular or rounded shape of glossa and paraglossa (P. abditus paratype).

FIGURES 35 – 41. Paracloeodes lotor n. sp. 35. foreleg; 36. shape of setae on dorsal margin of forefemur; 37. detail of foreclaw; 38. spines on posterior margin of abdominal terga; 39. gill IV; 40. cercus; 41. terminal filament.

FIGURES 42 – 43. Mississippi River, between Coon Rapids Dam and Dunn’s Island; photographs taken from Brooklyn Park (Hennepin County) side, 19 September 2014. 42. View upstream, towards Coon Rapids Dam; note repair work. 43. View downstream, towards Dunn’s Island.