Miroculis (Miroculis) niltoi Oliveira, Campos & Calor, 2020

Oliveira, Ian, Campos, Rogério & Calor, Adolfo R., 2020, New species of Miroculis Edmunds, 1963 (Ephemeroptera: Leptophlebiidae) based on nymphs and imagos from Chapada Diamantina’s Complex, Northeast Brazil, Zootaxa 4742 (3), pp. 543-554 : 544-553

Miroculis (Miroculis) niltoi Oliveira, Campos & Calor , sp. nov.

( Figures 1–25 )

Diagnosis. Miroculis (Miroculis) niltoi sp. nov. can be distinguished from congeners by the following characteristics: Male imago: (i) median region of styliger plate cleft in ventral view ( Fig. 4 ) and (ii) well-sclerotized ventrallydirected process on posteromedial margin of styliger plate ( Figs 4–5 ). Female imago: (iii) egg guide long, reaching sternum IX ( Fig. 8 ), and (iv) sternum IX about as long as wide, with shallow apical cleft and apex rounded ( Fig. 9 ).

Description.

Male imago ( Figures 1–5 )

MEASUREMENTS (mm). Body: 6.05–6.66 (n= 8); forewings: 5.28–5.65 (n= 7), angularity of cubital region: 96–105° (n= 2); hind wing: 1.32–1.59 (n= 6); foreleg: 4.90 (n= 1); middle leg: 2.40–2.64 (n= 2); hind leg: 2.84–3.15 (n= 2); caudal filament: 10.71–11.43 (n= 2).

RATIOS. Wings. Forewing width 0.38–0.43x forewing length; hind wing length 0.24–0.28x forewing length; hind wing width 0.42–0.56x hind wing length; forewing MA 2 fork 0.40–0.45x total MA length. Legs. Segments of foreleg: 0.66: 1.00 (1.85mm): 0.03: 0.36: 0.24: 0.17: 0.08; middle leg: 1.15: 1.00 (0.96mm): 0.05: 0.09: 0.04: 0.06: 0.09; hind leg: 1.12: 1.00 (1.02mm): 0.06: 0.09: 0.04: 0.05: 0.12. Genitalia. Styliger plate medial length 1.95–2.73x maximum width; lateral length 0.75–0.90x medial length; lateral length also 1.65–2.32x segment IX length. Forceps segment III length 0.58–0.73x forceps segment II length; forceps segment III length 0.24–0.31x forceps segment I length; forceps segment II length 0.39–0.43x forceps segment I length; penes length 2.70–4.70x forceps segment I length.

COLORATION AND MORPHOLOGY. Body. Light yellow brown ( Fig. 1 ). Head. Brown to dark brown, posterior margin V-shaped. Antenna with scape and pedicel brown to dark brown, flagellum brown, paler towards apex. Ocelli white with black ring on basal 2/3. Compound eye stalk yellow to light yellow, stalk as long as wide, without distomedial projection; upper portion separated by distance approximately equal to upper portion width; facets of upper portion yellow, separated by dark grooves, dorsal surface rounded, with 9–13 complete facets in longest row; lower portion of compound eye black; upper and lower portions of compound eye not touching each other. Thorax. Pronotum light brown to brown, medially lighter, lateral margins darker. Mesonotum dark brown. Metanotum brown. Pleural sclerites brown, darker on margins, membrane washed with grey. Prosternum brown. Meso- and metasterna light brown, except mesosternal apophysis brown. Wings. Forewing with membrane hyaline, washed with light brown at base and on pterostigma ( Fig. 2 ); bulla visible; up to five crossveins between C and Sc veins, basal to bulla; 8–19 crossveins between C and Sc veins and up to four forked crossveins distal to bulla; IMP connected to MP 1 and MP 2 by crossveins; MP 2 connected to MP 1 basally, sometimes not conspicuous; MP 2 connect- ed to CuA by crossvein; CuA and CuP connected by crossvein; CuP curving regularly; veins A 1 and A 2 connected basally by crossvein. Hind wing hyaline, washed with light brown at base and on apex of costal projection ( Fig. 3 ); costal projection weakly developed; vein Sc ending on costal margin; hind wing apex acute to rounded; fork R+MA asymmetric or symmetric; vein CuP present. Legs. Foreleg brown, lighter towards apex, washed with dark grey on femur and tibia, tarsal claws dissimilar, one spine-like, one paddle-like. Middle and hind legs light yellow brown washed with dark grey on femur and tibia. Abdomen. Light brown. Tergum I dark grey, except medial line hyaline. Terga II–VII with anterior 1/3 hyaline, dark grey on posterior 2/3, median line hyaline. Terga VIII–X dark grey, terga IX–X overall color pattern sometimes lighter. Sternum I brown. Sterna II–X light yellow grey. Genitalia. Light yellow brown to yellow brown. Styliger plate light yellow brown, median region cleft, with well-sclerotized ventrally-directed process on posteromedial margin ( Figs 4–5 ). Forceps segment I yellow brown on basal 2/3, dark grey on apical 1/3, subapical inner margin hyaline, medially narrow, outer margin with grooves, inner margin smooth, subapical inner margin not developed ( Fig. 4 ); forceps segment II grey, medially narrow; forceps segment III grey, apex slightly acute on posterolateral inner margin. Penes light brown, bending dorsally towards apex ( Fig. 5 ). Caudal filaments. Light yellow brown to brown.

Female imago ( Figures 6–9 )

MEASUREMENTS (mm). Body: 4.86–5.75 (n= 2); forewing: 5.32 (n= 1); hind wing: 1.11 (n= 1); legs and caudal filaments broken off and missing.

RATIOS. Wings. Forewing width 0.41x forewing length; hind wing length 0.38x forewing length; hind wing width 0.50x hind wing length; forewing MA 2 fork 0.43x total MA length. Abdomen. Egg guide length 1.61x sternum VIII length; sternum IX length 1.09x sternum IX width; sternum IX with median cleft length 0.04x sternum IX length.

COLORATION AND MORPHOLOGY. Body. Light yellow. Head. Light grey yellow, dark grey on edges, with two dark marks on posterior margin. Antenna with scape and pedicel washed with dark grey, flagellum broken off and missing. Ocelli white with black ring on basal 2/3. Compound eye black. Thorax. Pronotum light yellow, dark grey on edges. Meso- and metanota yellow brown, dark grey on sutures and edges. Pleural sclerites yellow brown, membrane washed with dark grey. Sterna light yellow brown, dark grey on edges. Wings. Forewing with membrane hyaline, washed with light brown at base and on pterostigma ( Fig. 6 ); bulla visible; four crossveins between C and Sc veins basal to bulla; 14–16 crossveins between C and Sc veins, forked crossveins distal to bulla absent; IMP connected to MP 1 and MP 2 by crossveins; MP 2 connected to MP 1 basally; MP 2 connected to CuA by crossvein; CuA and CuP connected by crossvein; CuP curving regularly; veins A 1 and A 2 connected basally by crossvein. Hind wing hyaline, washed with light brown at base and on apex of costal projection ( Fig. 7 ); costal projection developed; costal margin basal to costal projection almost straight; vein Sc ending on costal margin; hind wing apex acute; fork R+MA asymmetric; vein CuP present. Legs. Broken off and missing. Abdomen. Light yellow. Tergum I washed with dark grey, except by hyaline marks medially. Terga I–VII with median line hyaline, one pair of anterosubmedial hyaline marks. Terga I–VIII with posterior 2/3 washed with dark grey, darker on posterior margins. Terga IX–X hyaline, without apparent dark grey wash, tergum IX lighter than X. Sterna hyaline. Sterna I–IV each with median dark line and circular mark on anteromedial area, light dark grey on posterolateral region. Sternum VII with egg guide well-developed, reaching sternum IX, internal pair of egg ducts from segment V to VII ( Fig. 8 ). Sternum IX about as long as wide (1.09x its width), with shallow cleft, apex rounded ( Fig. 9 ).

Final nymphal instar ( Figures 10–24 )

MEASUREMENTS (mm). Body: 5.21–5.53 (n= 4); foreleg: 2.65–2.97 (n= 2); middle leg: 2.46–2.66 (n= 2); hind leg: 3.07–3.18 (n= 2); caudal filaments: 10.19 (n= 1).

RATIOS. Mouthparts. Mandible width 0.72–0.77x its length. Maxillary palp III length 0.44–0.46x palp II length; palp III 0.60–0.66x palp I length; palp II length 1.33–1.42x palp I length. Labial palp I width 1.84–2.10x palp I length; palp III length 0.43–0.44x palp II length; palp III length 0.48–0.51x palp I length; palp II length 1.11–1.14x palp I length. Paraglossa length 1.00–1.06x width. Legs. forefemur width 0.34x length. Middle femur width 0.29x length. Hind femur width 0.27x length. Abdomen. Dorsal portion of gill IV with medial filament length 1.10x length of main gill body.

COLORATION AND MORPHOLOGY. Body. Yellow brown in male, lighter in female. Head. Dark yellow brown, darker near antenna, hyaline surrounding ocelli. Antenna with scape and pedicel dark brown, flagellum brown, lighter towards apex. Ocelli white with black ring on basal 2/3. Upper portion of compound eye dark yellow brown, lower portion black. Epicranial suture hyaline. Clypeus slightly concave on anterior margin. Labrum anterolateral margins rounded ( Fig. 10 ). Mandible with anterior 2/3 washed with brown ( Figs 11–12 ), with curved row of setae medially. Hypopharynx superlingua with many setae on anterior margin ( Fig. 13 ). Maxilla with ca. 25 pectinate setae in subapical row ( Figs 14–15 ). Labium glossa bearing numerous setae ( Fig. 16 ). Thorax. Yellow brown, darker on sutures, mesonotum, and forewing pads. Hind wing pads light yellow. Pleura washed with dark grey. Sterna lighter than terga in male, white in female. Legs. Hyaline, washed with grey. Coxa light yellow, except dorsal edge washed with dark grey. Trochanter light yellow, except posterolateral ventral edge washed with dark grey ( Figs 17–19 ). Femur dark grey on median and apical regions, darker on apical region, dorsal and ventral edge with setae, longer on apical half of dorsal edge. Tibia dark grey, darker on basal region. Tarsi light yellow. Tarsal claw with subapical denticle much larger than other denticles. Foreleg color pattern darker than middle and hind legs. Abdomen. Light yellow brown. Male with tergum I washed with dark grey ( Fig. 20 ). Terga II–III each with posterior 2/3 washed with dark grey, darker on posterolateral region. Terga IV–V each with posterior 1/3 washed with dark grey, posterolateral region washed on posterior 2/3, forming U-shaped wash. Terga VI–VIII each with posterior 2/3 washed with dark grey, darker on posterolateral margins, with submedial hyaline marks on posterior area. Tergum IX washed with light dark grey on medial and lateral areas, producing somewhat I-shaped hyaline mark. Tergum X washed with dark grey on margins. Median line hyaline on terga II–IX. Female abdominal color pattern as in male, except terga III–VII each with posterior 3/4 washed with dark grey, narrow hyaline mark medially, dark marks on sublateral areas ( Fig. 21 ). Tergum VIII with medial region washed with dark grey, dark marks on anterosublateral and posterosublateral areas. Tergum IX washed with light dark grey, hyaline on medial region, producing V-shaped mark. Posterolateral spines on terga VI–IX, spines developed beyond posterior margins on terga VIII–X, spines well developed on tergum IX ( Figs 20–21 ). Gills with black tracheae, membrane washed with dark grey ( Fig. 22 ), trachea unbranched, dorsal portion with inner posterolateral projection more developed than outer projection. Dorsal portion of gill IV with medial filament length 1.10x length of gill body, apex of medial filament bifid ( Fig. 23 ). Sterna hyaline, washed with white on sterna I–V, yellow brown on sterna VI–VIII, darker towards sternum VIII, and yellow on sternum IX. Developing penes visible, projected beyond the segment IX ( Fig. 24 ).

Type material: HOLOTYPE. 1♂ — BRAZIL: Bahia: Mucugê , 13°01’42.7’’S, 41°22’03.2’’W, 984m, 24.i.2018, UV light pan trap, Calor A.R., Duarte T., Barata S. & Oliveira I. (MZUSP) . PARATYPES. 1♂, same data as ho- lotype (UFBA: E029) ; 1♂, same data as holotype (UFVB) ; 2♂, same data as holotype, except 12°59’44.9’’S, 41°19’36.3’’W, 974m, 12.vi.2015, Malaise trap, Dias. E. & Campos R. (UFBA: E016) ; 1♂, same data as holo- type, except 12°59’44.9’’S, 41°19’36.3’’W, 974m, D-net, v.2015, Campos R., reared (MZUSP) ; 1♂, same data as holotype, except 12°59’44.9’’S, 41°19’36.3’’W, 974m, viii.2015, Malaise trap, Calor A.R. et al. (UFVB) ; 2♂, same data as holotype, except 12°59’44.9’’S, 41°19’36.3’’W, 974m, 09.ii.2015, Malaise trap, Dias E. & Campos R. (MZUESC) ; 3♂, same data as holotype, except 12°59’44.9’’S, 41°19’36.3’’W, 974m, x.2015, Malaise trap, Calor A.R. et al. (MZUESC) ; 1♂, same data as holotype, except 12°59’44.9’’S, 41°19’36.3’’W, 974m, viii.2015, Malaise trap, Calor A.R. et al. (UFBA: E027) ; 1♂, same data as holotype, except 12°59’44.9’’S, 41°19’36.3’’W, 974m, 2015, Malaise trap, Dias E. & Campos R. (UFBA: E021) ; 2♂, same data as holotype, except, 12°59’44.9’’S, 41°19’36.3’’W, 974m, x.2015, Malaise trap, Calor A.R. et al. (UFVB) ; 1♂, same data as holotype, except 12°59’44.9’’S, 41°19’36.3’’W, 974m, 10.i.2015, Malaise trap, Dias E. & Campos R. (UFBA: E022) ; 1♀, same data as holotype, except, 12°59’44.9’’S, 41°19’36.3’’W, 974m, x.2015, Malaise trap, Calor A.R. et al. (MZUSP) ; 1♀, same data as holotype, except, 12°59’44.9’’S, 41°19’36.3’’W, 974m, x.2015, Malaise trap, Calor A.R. et al. (UFVB); 1 nymph, same data as holotype, except 12°59’51.9’’S, 41°20’28.0’’W, 950m, 05.viii–02.ix.2018, Me- deiros A. et al. (MZUSP); 1 nymph, same data as holotype, except 12°59’51.9’’S, 41°20’28.0’’W, 950m, 05.viii– 02.ix.2018, Medeiros A. et al. (MZUSP); 2 nymphs, same data as holotype, except 12°59’51.9’’S, 41°20’28.0’’W, 950m, 05.viii–02.ix.2018, Medeiros A. et al. (MZUSP); 1 nymph, same data as holotype, except 12°59’51.9’’S, 41°20’28.0’’W, 950m, 05.viii–02.ix.2018, Medeiros A. et al. (UFVB) ; 1♂, same data as holotype, except Andaraí , 12°57’0.81’’S, 41°16’37.0’’W, 871m, 20–21.i.2018, Pennsylvania trap, Calor A.R., Barata S., Oliveira I. & Duarte T. (MZUSP) .

Etymology. The specific name is in honor of Mr. Adenilton Oliveira, nicknamed “Nilton” by colleagues and friends. Nilton greatly supports scientific research in Parque Municipal de Mucugê, the type location of the new species, and performed a decisive contribution to our fieldtrips.

Distribution. Brazil: Chapada Diamantina’s Complex (Caatinga), Northeast Brazil ( Fig. 25 ).

Life cycle association. Rearing.

Discussion. Male imagos of Miroculis (Miroculis) niltoi sp. nov. are morphologically similar to Miroculis (Miroculis) samba Costa, Almeida & Salles, 2019 and Miroculis (Miroculis) wolverine Costa, Almeida & Salles, 2019 , by sharing similar penes length and curvature and by having the styliger plate longer than sternite VIII. However, the male imago of M. (M.) niltoi sp. nov. differs by having a forewing with light brown areas at the base and on the pterostigma, in contrast to the forewing being pigmented with brown on the Rs fork, crossveins apical to bulla and crossveins on pterostigma as in M. (M.) samba and M. (M.) wolverine . In addition, the new species differs by having penes with a smooth curve basally in lateral view, as opposed to the sinuous curve of M. (M.) samba , and having the outer margin of forceps segment I grooved instead of smooth as in M. (M.) wolverine .

Female imagos of M. (M.) niltoi sp. nov. are morphologically similar to those of M. (M.) samba by also having sternite IX with a shallow apical cleft. Nonetheless, the female imago of the new species differs from M. (M.) samba by the long egg guide, reaching sternum IX, as opposed to the wide egg guide, not reaching sternum IX, in M. (M.) samba . Additionally, the new species female exhibits a forewing that is pigmented with light brown only at the base and on the pterostigma, rather than pigmented with brown at the base, crossveins on pterostigma, and crossveins along the wing forming two conspicuous bands in M. (M.) samba .

The final nymphal instars of M. (M.) niltoi sp. nov. are morphologically similar to those of Miroculis (Miroculis) fittkaui Savage & Peters, 1983 and M. (M.) samba due to similar shapes of posterolateral projections of gills IV and the dark grey wash on femur posterior region, respectively. However, the new species’ final nymphal instars differ by their overall abdominal color pattern, especially on tergum VI, with the apical 2/3 washed with dark grey, while M. (M.) fittkaui and M. (M.) samba exhibit a distinct brown black mark with inverted V-shape and a brown wash on tergum VI, respectively. Furthermore, the new species’ final nymphal instars have gills with the medial filament longer than the body of the gill, instead of shorter than the body of the gill, as in M. (M.) fittkaui and lateral lobes present rather than absent, as in M. (M.) samba .

Although the taxonomy of nymphs within Miroculis is problematic, the final nymphal instars of M. (M.) niltoi sp. nov. can be distinguished by the following combination of characteristics: posterolateral spines on abdominal terga VI–IX, spines developed beyond the posterior margin of tergum on terga VIII–IX, spines well developed on tergum IX ( Figs 20–21 ); dorsal portion of gill IV with medial filament length 1.10x length of gill body ( Fig. 22 ); dorsal portion of gill IV with apex of medial filament bifid ( Fig. 23 ); and developing penes visible, projected beyond the segment IX ( Fig. 24 ).

Biology. Although male penes morphology is intimately related with female genital aperture as both are directly associated to mating ( Kluge 2004), here we report an observed positive correlation between penes and egg guide length in M. (M.) niltoi sp. nov. The female imago of the new species displays an extremely long egg guide (reaching sternum IX) in comparison with short egg guide (not reaching sternum IX) in female imagos of other species. Concurrently, the male imago possesses an extremely long paired penes, suggesting the accordant positive correlation of length of these genital structures in the new species.

Imagos of M. (M.) niltoi sp. nov. were collected at dusk. Collection records suggests that the emergence pattern of the new species is nonseasonal, as is the case with many other tropical mayfly species. Specimens were collected throughout much of the year, especially January to February and July to August.

Figures

FIGURE 1. Miroculis (Miroculis) niltoi sp. nov., male imago, body (wings in part and genitalia detached).

FIGURES 2–5. Miroculis (Miroculis) niltoi sp. nov., male imago, wings and genitalia: 2, right forewing, dorsal view; 3, left hind wing, dorsal view; 4, genitalia, ventral view; 5, genitalia, lateral view.

FIGURES 6–9. Miroculis (Miroculis) niltoi sp. nov., female imago (paratype MZUSP, except paratype UFVB for figure 6): 6, right forewing, dorsal view; 7, right hind wing, dorsal view; 8, egg guide, lateral view; 9, sternum IX, ventral view.

FIGURES 10–16. Miroculis (Miroculis) niltoi sp. nov., final nymphal instar, mouthparts, dorsal view (paratype MZUSP): 10, labrum; 11, left mandible; 12, right mandible; 13, hypopharynx; 14, left maxilla; 15, right maxilla; 16, labium.

FIGURES 17–24. Miroculis (Miroculis) niltoi sp. nov., final nymphal instars; legs, abdominal color pattern, and gill IV (paratypes MZUSP): 17, foreleg, dorsal view; 18, middle leg, dorsal view; 19, hind leg, dorsal view; 20, male abdominal color pattern, dorsal view; 21, female abdominal color pattern, dorsal view; 22, right gill IV, dorsal view; 23, medial filament apex of gill IV; 24, developing genitalia, ventral view.

FIGURE 25. Occurrence of Miroculis (Miroculis) niltoi sp. nov. within Chapada Diamantina’s Complex (Caatinga), Northeast Brazil.