Paracloeodes minutus ( Daggy 1945 )

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 : 335-339

Paracloeodes minutus ( Daggy 1945) (comb. by Edmunds et al. 1976)

= Pseudocloeon minutum Daggy, 1945 (orig.)

= Paracloeodes abditus Day, 1955 (syn. by McCafferty & Waltz 1990)

Diagnoses. Male imago. 1) forewing with parallel marginal intercalary veins; 2) hind wing absent ( Fig. 3 ); 3) posterior margin of styliger plate straight ( Figs. 12 and 13 ); 4) posterior margin of styliger plate without spine ( Figs. 12 and 13 ).

Mature nymph. 1) labrum with a pair of subapical setae near middle distinguishable from others dorsal setae; 2) labrum with one row of five simple setae near distolateral margin; 3) distal margin of labrum with bifid setae; 4) distolateral margin of labrum with bifid and strong pectinate setae; 5) right mandible incisors cleft; 6) outer incisor of right mandible without vestigial denticle; 7) maxillary palp 1.60× the length of galea-lacinia; 8) apical half of paraglossa without an abrupt decrease in width ( Figs. 22 and 25 ); 9) angle between inner margin of labial palp segment III and distal margin of segment II around 90°; 10) lobe of labial palp segment II rounded ( Fig. 19 ); 11) base of labial palp segment III 0.43 – 0.46× the width of labial palp segment II ( Fig. 19 ); 12) labial palp with length of segment III 0.80 – 0.85× the width of its base ( Fig. 19 ); 13) hind wing pads absent; 14) anterior surface of forefemur with one row of blunt setae near dorsal margin ( Fig. 16 ); 15) medial row of setae on anterior surface of forefemur dense ( Fig. 16 ); 16) anterior surface of forefemur with dense row of blunt setae near ventral margin ( Fig. 16 ); 17) tarsal claw 0.5× the length of tarsus, with minute denticles ( Fig. 16 ); 18) abdominal color pattern as in Figure 4 ; 19) length of gills 2.0× the subsequent abdominal segment or longer ( Fig. 4 ).

Distribution. Belize, Costa Rica, Honduras, Nicaragua (Central American countries), Quebec ( Canada), Baja California Sur, San Luis Potosi ( Mexico), Alabama, Arizona, California, Colorado, Georgia, Idaho, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Minnesota, Mississippi, Missouri, Montana, Nebraska, New York, North Carolina, North Dakota, Ohio, Oregon, South Carolina, South Dakota, Texas, Wisconsin, Wyoming ( U.S.A.) (Daggy 1 945; Day 1955; Sarver & Kondratieff 1997; Randolph & McCafferty 1998; DeWalt et al. 1999; McCafferty & Lenat 2004; Guenther & McCafferty 2005, 2008; McCafferty 2009, 2011; McCafferty et al. 2010, 2012; Klubertanz 2016).

Comments. Edmunds et al. (1976) noted that the type locality of P. abditus “has been dredged, diverted, and dammed and has suffered pollution from irrigation runoff, crop dusting, sewage, and industry.” The type locality of P. minutus ( Figs. 42, 43 ), on the other hand, remains in good biotic condition, but we did not collect any individuals of P. minutus during our September 2014 and May 2015 visits to the site. Although Daggy (1945) described nymphs for P. minutus from the type locale, these were not associated by rearing. Given that we now know at least two species are present at the type locale, we cannot be sure of a nymph being associated with the type concept of P. minutus . We did, however, confirm the nymph-imago association in P. abditus , and we confirmed that P. minutus and P. abditus male imagos share all diagnostic features.

Paracloeodes minutus is listed as a species of Special Concern in Wisconsin, but the small nymphs are good swimmers, probably spending most of their lives in deeper sandy habitat, being most easily collected as later instars ( Lillie 1995; Klubertanz 2016).

We note that we do not know the extent of variation of speckling of the thorax ( Klubertanz 2016: Fig. 98) and pigmentation of intersegmental areas of the abdominal sterna ( Klubertanz 2016: Fig. 20 b) of nymphs of this species and others; such speckling and pigmentation has been observed to be variable in this species and P. fleeki from the U.S. A Southeast (Steven Beaty, Eric Fleek, Victor Holland, pers. comms.), but some western Paracloeodes may lack it entirely (Jeff Webb, pers. comm.). Most of our historical specimens are faded, and so we do not provide a detailed evaluation here.

Material examined. One male imago, one set exuviae and one nymph on slide ( P. abditus paratypes), USA, California, Modesto , Toulumne River , 7.vii.1954, W. C. Day col. [ PERC] . One male imago, dried on pin ( P. minutus holotype), USA, Mississippi River, Coon Rapids , Minnesota, 7.vi.1937 [UMN].

Figures

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 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 14 – 16. Forelegs of nymphs. 14. Paracloeodes fleeki (paratype), red lines demonstrate how ratios were measured, regular arrow indicates the ventral row of setae of femur, bracket indicates the row of blunt setae near ventral margin, dashed line rectangle indicates the medial row of setae on anterior surface of forefemur, dashed line ellipse indicates the row of blunt setae near dorsal margin, the dashed line arrow indicates the dorsal row of setae on femur; 15. Paracloeodes lugoi (holotype); 16. Paracloeodes minutus (paratype of P. abditus).

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.