Minagrion mecistogastrum (Selys, 1876)

Vilela, Diogo Silva, Anjos-Santos, Danielle, Koroiva, Ricardo, Cordero-Rivera, Adolfo & Guillermo-Ferreira, Rhainer, 2020, Revision of the genus Minagrion Santos, 1965 (Odonata: Coenagrionidae), Zootaxa 4786 (2), pp. 176-198 : 184-187

Minagrion mecistogastrum (Selys, 1876)

Figs. 1d (♂ hab), 2g–h (♂ and ♀ tub), 3m–p (♂ app), 4d (♂ lig), 5h (♀ hab), 6d (♀ lob), 7c (♀ ptx), 10d (alive ♂ specimen)

Telagrion mecistogastrum, Selys (1876) : 257, 262−263 (original description ♂ and ♀).

Minagrion mecistogastrum (Selys, 1876) — Santos (1965b): 9 (new combination by designation);— Garrison (1991): 13 (synonymic list);— Costa et al. (2000): 12 (species list, records, distribution, references);— Lencioni (2006): 171 (illustrated guide, distribution);— Heckman (2008): 299, 336 (key, illustrations, distribution);— Garrison et al. (2010): 287, 289 (synonymic list, illustrations: figs. 1850 and 1851 as M. ribeiroi );— Lencioni (2017): 247, 383−396 (diagnosis, illustrations, distribution); — Dalzochio et al. (2018): 6 (distribution in Rio Grande do Sul State).

Holotype ♂ and allotype ♀: BRAZIL, Rio de Janeiro State, Copacabana, W. de Selys and E. de Selys leg., in IRSBN [not ex- amined]

Specimens examined. Total: 21♂♂, 11♀♀. 1♂ BRAZIL, São Paulo State, Jacareí, Fazenda Santana do Rio Abaixo , 25.x.2001, F.A.A. Lencioni leg., in LENCIONI ; 1♂, 2♀♀ BRAZIL, São Paulo State, Salesópolis (23°35’51”S, 45°43’41”W), 1074 m, 29.i.2011 (♂), 22.i.2011 (♀), 19.ii.2011 (♀), F.A.A. Lencioni leg., in LENCIONI ; 2♂♂ BRAZIL, São Paulo State, Barueri, Estrada de São Paulo, 12.iii.1957 and 28.xii.1957, K. Lenko leg., in ABMM ; 4♂♂, 6♀♀ BRAZIL, Rio de Janeiro State, Angra dos Reis, ii.1944 (2♂♂, 6♀♀), iv.1945 (2♂♂), L. Travassos and H. Travassos leg, in MNRJ ; 1♂, 1♀ BRAZIL, Rio de Janeiro State, Angra dos Reis, Japuhyba , 17.iv.1942, H. Travassos leg., in MNRJ ; 2♀♀ BRAZIL, Rio de Janeiro State, Engenheiro Paulo de Frontin , 02.i.1958, N.D. Santos and J. Magalhães leg., in MNRJ ; 10♂♂ BRAZIL, Rio de Janeiro State, Engenheiro Paulo de Frontin, Açude Dr. Portugal, 02.vi.1957, N.D. Santos and J. Magalhães leg., in MNRJ ; 2♂♂ BRAZIL, Santa Catarina State, Joinville , xii.1957 J. Lane leg and 7.xii.1983 (no information on the collector), in ABMM .

Additions to the original male description. Head ( Fig. 1d ). Dorsally black with dark metallic green reflections; postocular spots light blue, elongated, merging with the occipital bar, which has the same coloration; frons angulated; antefrons, postfrons, clypeus, postclypeus, labrum and mandibles greenish; ventral face of the head greyyellow or bluish adjacent to the eye, remainder black.

Thorax ( Fig. 1d ). Anterior lobe of prothorax blue anteriorly, with a black posterior stripe, medial lobe black dorsally with semicircular blue lateral spots, posterior lobe black with blue on the lateral margins, bilobed; pterothorax black dorsally with metallic blue reflections, remainder predominantly blue except for a thin posterior black stripe in the humeral suture; a wide black stripe covering about 1/2 of the anterior mesepimeron; mesinfraepisternum dark brown and a black spot on the posterior portion of interpleural suture.

Legs ( Fig. 1d ). Pale, femoral armature black, small darker areas on tibiae armature; tarsal apex and claws dark, the supplementary tooth on tarsal claw well developed.

Wings ( Fig. 1d ). Hyaline, pterostigma dark brown, 1 cell long; 10 Px in HW, 12 Px in FW; CuA extending for 11 cells distal to vein descending from subnodus in FW, 10 in HW; MP reaching wing posterior margin in FW, in HW merged to MP&AA, not reaching wing margin;

Abdomen ( Figs. 1d , 2g ). S1 with a black quadrangular dorsal spot, occupying about 1/3 of the segment, remain- der blue; tubercle sub rectangular, digit-like shape with a darker and rounded apex bearing several apical setae (setae omitted in the drawing); S2 with a black sub triangular dorsal spot, blue in dorsolateral view; S3−7 black dorsally, remainder pale blue, with incomplete pale basal rings; S8 black dorsally except for a posterior triangular blue spot, lateral anterior 1/2 pale, remainder black; S9 blue dorsally, remainder black; S10 blue, with a posterior dorsal cleft, with rounded borders.

Genital ligula ( Fig. 4d ). Segment one with a pair of digit−like lateral sclerotized processes, similar to lobes, in the flexure; inner fold sub triangular in lateral view, proximal to flexure. Segment two large with an entire rounded apex, and two lateral lobes.

Anal appendages ( Fig. 3 m–p). Cercus forcipate, shorter than S10; longitudinal ridge dividing the cercus into a dorsal plate, thin and flat on the apical 1/3 and a ventrobasal expansion approximately 1/2 the length of the appendage, roughly triangular; apex sclerotized, bearing one strong tooth and one or two smaller teeth. Paraprocts small, not seen in lateral view, apex acute and directed upwards.

Measurements. Total 54−61; abdomen 48−50; FW 20−23; HW 16−21.

Additions to the original female description. Head ( Fig. 5h ). Similar to male, except: blue-green postocular spots and occipital bar; postfrons light brown; antefrons, postclypeus, clypeus, labrum, labium and mandible base olive green; back of the head pale; semicircular light brown spot on the occipital foramen.

Thorax ( Figs. 5h , 6d , 7c ). Anterior lobe of prothorax blue medially, pale laterally; medial lobe brown medially, pale blue laterally; posterior lobe in dorsal view semicircular, trilobed: medial lobe bent posteriorly, its margin entire and the two lateral lobes small and slightly erected above the medial lobe ( Fig. 6d ); posterior margin of prothorax a continuous line in lateral view, notopleural suture sinuous. Pterothorax black dorsally with violet metallic reflections, mesinfraepisternum brown, connected to a thin stripe on 1/2 mesepimeron; remainder pale green or olivegreen.

Legs ( Fig. 5h ). Pale, femoral armature light brown, small darker areas on tibial armature; tarsal apex and claws dark, the supplementary tooth on tarsal claw well developed.

Wings ( Fig. 5h ). Hyaline, pterostigma brown, 1 cell long; 12 Px in HW, 13 Px in FW; CuA extending for 11 cells distal to vein descending from subnodus in FW, 9 in HW; MP reaching wing posterior margin in FW, in HW merged to MP&AA, not reaching wing margin.

Abdomen ( Figs. 2h , 5h ). Entirely black dorsally, pale laterally; tubercle digit like with rounded apex (smaller than in the male); S7−10 with green metallic reflections; genital valves at the same level or slightly surpassing the posterior margin of S10 and never reaching the tip of cercus.

Measurements. Total 43.5−45; abdomen 35.8−37; FW 21.8−22; HW 20.8−21.

Diagnosis. Easily separated from its congeners by its large size, which in the field can be confused with Pseudostigmatines ( Figs. 1d , 5h ). Apart from size differences, males of M. mecistogastrum can be separated from other Minagrion males by the following character combination: cercus shorter than S10 (only shared with M. ribeiroi ) ( Fig. 3 m−p), narrow dorsal plate, more pronounced at apical 1/3 of cercus (shared with M. canaanensis , however, it is much larger on the latter), paraproct reduced, not seen in lateral view; tubercle digit like with rounded apex (similar to M. waltheri ) ( Fig. 2g ); segment two of genital ligula long with an entire rounded apex (long with a bifid apex in M. canaanense , shorter on the other species). Females can be separated from other females by posterior lobe morphology ( Fig. 6d ) and posterior margin of prothorax in lateral view, which forms a continuous line ( Fig. 7c ). In other species, lateral margin of prothorax interrupted by margin of the posterior lobe.

Distribution. This species seems to be restricted to the Southeastern and Southern regions of Brazil, occurring in the States of Rio de Janeiro, São Paulo, Santa Catarina and Rio Grande do Sul. It is very likely to occur also in Paraná and Minas Gerais States, which are inside the occurrence range; however, it has not been reported from these states.

Figures

FIGURE 1. Male habitus: (a) caldense, São Roque de Minas, at ECOEVO; (b) caldense, Poços de Caldas, at FAAL; (c) canaanense, Santa Tereza, at FAAL; (d) mecistogastrum, Salesópolis, at FAAL; (e) ribeiroi, Recreio dos Bandeirantes PARATYPE, at FAAL; (f) waltheri, São Gonçalo do Rio Preto, at ABMM.

FIGURE 2. S1 tubercle; (a) ♂ caldense, Poços de Caldas, at FAAL; (b) ♂ caldense, São Roque de Minas, at LESTES; (c) ♀ caldense ALLOTYPE, Poços de Caldas, at MNRJ; (d) ♀ caldense, SCNP, at ECOEVO; (e) ♂ canaanense, Santa Tereza, at FAAL; (f) ♀ canaanense ALLOTYPE, Santa Tereza, at MNRJ; (g) ♂ mecistogastrum, Salesópolis, at FAAL; (h) ♀ mecistogastrum, Salesópolis, at FAAL; (i) ♂ ribeiroi, Recreio dos Bandeirantes PARATYPE, at FAAL; (j) ♀ ribeiroi, Salesópolis, at FAAL; (k) ♂ waltheri, São Gonçalo do Rio Preto, at ABMM; (l) ♀ waltheri, São Gonçalo do Rio Preto, at ABMM.

FIGURE 3. Male anal appendages; (a–d) ♂ caldense, Poços de Caldas, at FAAL; (e–h) ♂ caldense, São Roque de Minas, at LESTES; (i–l) ♂ canaanense, Santa Tereza, at FAAL; (m–p) ♂ mecistogastrum, Salesópolis, at FAAL; (q–t) ♂ ribeiroi, Recreio dos Bandeirantes PARATYPE, at FAAL; (u–x) ♂ waltheri, Jaboticatubas, at FAAL.

FIGURE 4. Male genital ligula; (a) caldense, Poços de Caldas PARATYPE, at MNRJ probably lost; (b) caldense, SCNP PARA- TYPE of M. franciscoi, at ABMM; (c) canaanense, Santa Tereza, at RWG; (d) mecistogastrum, Cachoeira de Macacu, at RWG; (e) ribeiroi, Recreio dos Bandeirantes, at RWG; (f) waltheri, São Gonçalo do Rio Preto, at ABMM.

FIGURE 5. Female habitus; (a–c) juvenile caldense, SCNP, at LESTES; (d–f) mature caldense, SCNP, at LESTES; (g) caldense, Poços de Caldas PARATYPE, at ABMM; (h) mecistogastrum, Salesópolis, at FAAL; (i) ribeiroi Salesópolis, at FAAL; (j) waltheri, São Gonçalo do Rio Preto, at ABMM.

FIGURE 6. Female posterior lobe of prothorax; (a) caldense, Poços de Caldas ALLOTYPE, at MNRJ; (b) caldense, SCNP, at ECOEVO; (c) canaanense, Santa Tereza ALLOTYPE, at MNRJ; (d) mecistogastrum, Salesópolis, at FAAL; (e) ribeiroi, Salesópolis, at FAAL; (f) waltheri, São Gonçalo do Rio Preto, at ABMM.

FIGURE 7. Female prothorax in lateral view; (a) caldense, Poços de Caldas PARATYPE, at ABMM; (b) canaanense, Santa Tereza ALLOTYPE, at MNRJ; (c) mecistogastrum, Salesópolis, at FAAL; (d) ribeiroi, Salesópolis, at FAAL; (e) waltheri, São Gonçalo do Rio Preto, at ABMM.