Paracloeodes eurybranchus Lugo-Ortiz & McCafferty 1996

Emmerich, Daniel & Molineri, Carlos, 2020, Description of the male imago of Paracloeodes eurybranchus Lugo-Ortiz & McCafferty 1996 (Ephemeroptera: Baetidae), Zootaxa 4808 (2), pp. 393-396 : 393-395

Paracloeodes eurybranchus Lugo-Ortiz & McCafferty 1996 ( Figs. 1–9 )

Male imago. Lengths (mm): body: 4.6–5.0; cerci: 7.7–8.5; forewing: 4.6–5.0; hind wing: 1.0–1.1; tibia I: 1.4 mm; tibia II: 0.8 mm; tibia III: 0.8 mm. Head ( Figs. 1–2 ). Coloration whitish, shaded brown almost completely; compound eyes grayish, turbinate portion orangish. Antenna with scape and pedicel light brown, flagellum lighter. Dorsal portion of turbinate eyes oval; length 1.6–1.8x width; stalk height 0.5x width of dorsal portion; inner margins not parallel, divergent anteriorly ( Fig. 2 ). Thorax ( Fig. 1 ). Nota dark brown, except membranes yellowish white; anteronotal protuberance rounded. Pleurae and sterna dark brown with whitish membranes tinged with orange in prosternum and mesopleurae (in vivo). Legs yellowish shaded slightly with gray distally on femora. Foreleg measurements (in mm, mean values from 4 specimens): femur 0.95, tibia 1.44, tarsite I 0.05, tarsite II 0.58, tarsite III 0.50, tarsite IV 0.29, tarsite V 0.18. Middle and hind leg measurements (in mm, mean from 4 specimens): middle femur 0.72, middle tibia 0.76, middle tarsus 0.42, hind femur 0.69, hind tibia 0.74, hind tarsus 0.4. Forewing ( Fig. 7 ): membrane hyaline except at base, anteriorly to costal brace, brownish; veins light yellow, stigmatic area with 6–8 cross veins, mostly incomplete (not reaching subcostal vein). Marginal intercalary veins paired and long (1–1.5 times the width of the space between veins), except single between veins ICu2 and A, length of forewing about 2.4× width. Hind wing hyaline with two complete longitudinal veins; costal process subquadrate and located on basal third ( Fig. 8 ).

Abdomen ( Figs. 3–4 ). Terga orangish light brown, slightly darker on VII–X, with paired and small submedian marks in all terga. Sterna whithish light brown; sterna I–VII with a pair of submedian oblique dashes anteriorly and a pair of submedian dots at midlength; sterna VIII and IX with submedian longer and parallel dashes. Genitalia ( Fig. 9 ): styliger plate whitish yellow, apical margin and base of pedestals brownish, posterior margin of subgenital plate convex, with a small subquadrate median projection ( Fig. 9 ), in some specimens this is more rounded ( Fig. 9 ). Forceps whitish, segment I cylindrical, without distomedial projection; segment II narrow submedially; segment III elongate, 3.1–3.6 times longer than width. Forceps segment length (mm, mean values from 4 specimens): segment I 0.17, segment II 0.46, segment III 0.21. Cerci whitish.

Female imago. Length (mm). body: 4.0–5.0; cerci: 5.0–7.0; forewing: 4.3–5.1; hind wing: 0.8–1.1. General aspect and coloration as in figures 5 and 6.

Material examined. 143 nymphs, 21 male imagoes, 21 female imagoes, Argentina, Córdoba province, Nono, Río Los Sauces , S 31° 47 ̛ 50̛̛ ̛– W 65° 01 ̛ 02̛̛ ̛, 855 masl, 16/ V/15 , Emmerich D. & Molineri C, cols .

Discussion. Paracloeodes eurybranchus shares most of the diagnostic characteristics with P. charrua Emmerich & Nieto 2009 , P. ibicui Lugo-Ortiz & McCafferty 1996 , and P. prismatobranchus Cruz, Salles & Hamada 2018 : hind wings present, medial projection of the styliger plate and anterior wing with hyaline stigmatic area ( Lima et al. 2013; Cruz et al. 2018). In addition to these three characters, it shares with P. charrua the convex styliger plate. P. atroari Nieto & Salles 2006 and P. binodulus Lugo-Ortiz & McCafferty 1996 also present convex styliger plate, this being the only character shared by these two species and P. eurybranchus . P. charrua differs from this by the length of intercalary veins (short in P. charrua , long in P. eurybranchus ), general coloration of abdomen (terga light brown, segments II–VI lighter in P. charrua , in P. eurybranchus terga orangish light brown, slightly darker on VII–X, with paired and small submedian marks in all terga) and medial projection of the styliger plate (small and pointed in P. charrua but small and subquadrate in P. eurybranchus ). In the phylogeny proposed by Cruz et al. (2018a) P. eurybranchus is sister to P. assu Nieto & Salles 2006 , synapomorphies supporting this node are from the nymphal stage ( P. assu is only known from nymphs).

Figures

FIGURES 1–6. Paracloeodes eurybranchus, adult. Male imago: 1, general habitus, lateral view; 2, head, dorsal view; 3, abdomen, dorsal view; 4, abdomen, ventral view. Female imago habitus: 5, dorsal view; 6, ventral view.

FIGURES 7–9. Paracloeodes eurybranchus, male imago: 7, forewing; 8, hind wing, arrow indicates an unfolded costal process (from another specimen); 9, genitalia, arrows indicate a variation in medial projection.