Mythimna (Pseudaletia) celiae, Madruga & Specht & Blas & Mielke & Casagrande, 2022

Madruga, Janaína, Specht, Alexandre, Blas, German San, Mielke, Olaf H H & Casagrande, Mirna M, 2022, Revision of the species of Mythimna Ochsenheimer, 1816 (Pseudaletia Franclemont, 1951) (Lepidoptera: Noctuidae: Noctuinae: Leucaniini) occurring in Brazil, Revista Brasileira de Entomologia (e 20220026) 66 (3), pp. 1-21 : 15-17

Mythimna (Pseudaletia) celiae sp. nov. ( Figs. 1 , 12 )

urn:lsid:zoobank.org:pub:D5D278A9-5ADB-476F-BB20-08FA292D1434

Diagnosis

Both sexes with forewing ground color cream, usually mixed with dark scales, on most specimens without dark patch covering cubital vein. In males, cucullus with dorsal margin straight, ending in at least two distal processes, ampulla distinct, as a small ear-shaped dorsal projection, digitus slim, between a third of or as long as the clasper; vesica basal diverticulum elongate, with over four cornuti close to each other. Genitalia similar to Mythimna (P.) unipuncta , differing slightly in external morphology, DNA Barcode (COI) and specific localities.

Description

MALE. Head: Cream, sometimes mixed with dark scales of different hues. Eyes brown, pilose. Antenna filiform, triangular in cross section, covered dorsally with beige scales, ventrally naked, with tiny chemoreceptive trichoid sensilla, more concentrated in the central part of the antennomer and with longer lateral chemoreceptive trichoid sensilla, half as long as antennomer width. Thorax: Ground color as head; patagium with dark subapical line. Forewing: length - 1.5-1.9cm (n=20). Ground color cream, varibale mixed with dark scales of different hues; postmedial line as dark spots over the veins and terminal line as dark spots between veins, other transversal lines absent; with an oblique line of dark scales from the apex to M 2, on some specimens with an anterior area lighter than ground color; a dark patch with a spot of central white scales next to the bases of M 2 and M 3, undifferentiable in many specimens; dark patch covering cubital veins absent on most specimens; orbicular and reniform spots circular, inconspicuous, orange with smooth darker center, undifferentiable in some specimens; subterminal area of the wing with white or light beige scales over the veins; fringe beige with dark medial and terminal lines. Hindwing pale, with marginal brown shading toward the base, fringe pale. Abdomen: Greyish-cream dorsally; ventral view as head, with two faint black transversal lines subventral. Genitalia: Tegumen and uncus fused, the first wider than the base of uncus; ventral arms of tegumen slim, covered with setae posteriorly, close to the articulation with the dorsal arms of saccus. Saccus subquadrangular and bent toward the ventral arms of the tegumen, irregular distally, twisted toward its inner surface. Uncus elongated, flat and bent ventrally, widened on medial area, apical half abruptally narrowed to 1/5-1/6 of its width, covered with setae dorsally. Valva subtriangular; sacculus projected ventrally forming an ovallobe; cucullus long, with a straight dorsal margin and ending in at least two distal processes, distal portion lobate, corona present, with multiple rows of spines; clasper short; ampulla distinct, as a small ear-shaped dorsal projection; digitus slim, 1/3 as long as the clasper, on some speciemens it could be as long as clasper. Fultura inferior (=juxta) subtriangular, approximately one fourth the length of the ventral arms of tegumen and thrice as long as its smallest width, distal portion bifid. Aedeagus pipe-shaped; vesica tubular and elongate, slightly widened apically, with a continuous band of cornuti from posterior the diverticulum to subapical area, basal diverticulum elongate, with over four closely arranged cornuti, the distalmost thinner and longer than the others.

FEMALE. Similar to male, but antenna with tiny chemoreceptive trichoid sensilla only, longer lateral chemoreceptive trichoid absent. Forewing length 1.6-1.9cm (n=14). Abdomen: Genitalia almost entirely sclerotized. Eighth tergite straight and narrow. Papilla analis subtriangular covered with setae.Lamella antevaginalis subrectangular. Ductus bursae sclerotized, with a wide fold at its final portion leading to appendix bursae; corpus bursae membranous and round; appendix bursae with at least twice the length of ductus bursae, but with the same width, sclerotized basally and with membranous apex. Ductus seminalis originating on appendix bursae apex.

Geographic distribution

In Brazil, it is endemic to Rio Grande do Sul State, with records from Bagé, Passo Fundo, and Vacaria municipalities. It probably occurs in Uruguay and Northern Argentina as well, in view of the records of Mythimna (P.) unipuncta to these localities that are probably misidentifications.

Host plants

Unknown. Presumably grasses ( Poaceae ), as the other species in this study.

Etymology

Homage to Célia Pedrotti Madruga, the first author’s beloved grandmother, whose life was spent in the same meadows where this moth occurs.

Discussion

Mythimna (P.) celiae sp. nov. has the forewings cream colored, variable mixed with dark scales of different hues, but considerably lighter than the other species and the cubital vein not covered by a dark patch. However, this is a variable character, rendering it not the most reliable character for the species identification. Regarding the genitalia, the species can be easily distinguished from Mythimna (P.) adultera and from Mythimna (P.) sequax , with no need of dissection; the former presents the final portion of the dorsal margin of the cucullus protuberant, while in the latter it is bent dorsally, while Mythimna (P.) celiae sp. nov. has the dorsal margin of the cucullus straight, similarly to Mythimna (P.) unipuncta . It can be distinguished from the latter in details, such as the presence of more than one distal process at the tip of the cucullus. During the examination of the material from collections, we found many specimens identified as Mythimna (P.) unipuncta , that are, in fact, Mythimna (P.) celiae sp. nov.

Comparisons were made between specimens of Mythimna (P.) celiae sp. nov. and the descriptions of Mythimna (P.) punctulata ( Blanchard, 1852) that occurs in Chile ( Blanchard, 1852; Butler, 1882; Franclemont, 1951; Angulo and Weigert, 1977; Parra et al., 1986; Poole, 1989; Artigas, 1994; Olivares et al., 2009) and, possibly, Argentina ( Artigas, 1994; Pastrana, 2004), Brazil and Peru ( Artigas, 1994). However, the comparative study both of the external morphology and the genitalia ( Franclemont, 1951; Angulo and Weigert, 1977), indicated that none of the examined specimens are Mythimna (P.) punctulata . This reinforces the need for more comprehensive studies to elucidate whether the geographic distribution of Mythimna (P.) punctulata is restricted to Chile, or also covers eastern South America, as described in Artigas (1994).

Considering that Mythimna (P.) adultera , Mythimna (P.) sequax and Mythimna (P.) celiae sp. n. are sympatric in Rio Grande do Sul, Brazil, it stands to reason that the identification of the first two may be mistaken (ex. Biezanko et al., 1949; Biezanko and Bertholdi, 1951; Bertels, 1956; Corseuil, 1958; Costa, 1958; Bertels and Baucke, 1966). Likewise, the records for the neighboring countries Uruguay and Argentina of Mythimna (P.) unipuncta and/or Mythimna (P.) punctulata ( Artigas, 1994; Pastrana, 2004) may be misidentifications.

In this work, the estimates of evolutionary divergence between the species have shown higher interspecific than intraspecific divergence, and both the tree build using neighbor-joining and the one using maximum likelihood distinguish Mythimna (P.) celiae sp. nov. from Mythimna (P.) unipuncta . Thus, despite the low sample number, molecular, morphological, and geographic distribution data contribute integratively to the diagnosis of Mythimna (P.) celiae sp. nov.

Type material

Male holotype deposited at the DZUP, with the following labels: / HOLOTYPUS / Brasil, Rio Grande do Sul, Bagé, 31°21’4.94”S, 54°1’12.51”W, 232m, 06-XI-2015, R. N.Systi, J.U. P.Corrêa, M.A.P.da Silva & Harry Ebert leg./ DZ 39.913 / Holotypus Mythimna (Pseudaletia) celiae Madruga, Specht, San Blas, Mielke & Casagrande, 2022 /

Female allotype deposited at DZUP, with the following labels: / ALLOTYPUS / Brasil, Rio Grande do Sul, Bagé, 31°21’4.94”S, 54°1’12.51”W, 232m, 06-XI-2015, R. N. Systi, J. U. P. Corrêa, M. A. P. da Silva & Harry Ebert leg./ DZ 39.911 / Allotypus Mythimna (Pseudaletia) celiae Madruga, Specht, San Blas, Mielke & Casagrande, 2022 /

Paratypes: BRAZIL - Rio Grande do Sul: Bagé - 31°18’57.08”S, 53°59’52.91”W, 242m, 1 female, 4-I-2016, R.N.Systi, J. U.P.Corrêa, M.A. P. da Silva & Harry Ebert leg., DZ 39.918 , 1 male, 11-III-2016, R. N. Systi, J. U. P. Corrêa, M. A. P. da Silva & Harry Ebert leg., DZ 39.968 ( DZUP) , 31°21’4.94”S, 54°1’12.51”W, 232m, 1 female, 11-VI-2015, R. N. Systi, J. U. P. Corrêa, M. A. P. da Silva & Harry Ebert leg. ( CPAC) , 1 male, 11-VIII-2015, R. N. Systi, J. U. P. Corrêa, M. A. P. da Silva & Harry Ebert leg., DZ 39.966, 2 females, 1 male, 12-VIII-2015, R. N. Systi, J. U. P. Corrêa, M. A. P. da Silva & Harry Ebert leg., DZ 39.985 ( DZUP, CPAC) , 1 male, 13-VIII-2015, R. N. Systi, J. U. P. Corrêa, M. A. P. da Silva & Harry Ebert leg., DZ 37.891 ( DZUP) , 1 male, 14-VIII-2015, R. N. Systi, J. U. P. Corrêa, M. A. P. da Silva & Harry Ebert leg. ( CPAC) , 2 females, 7-X-2016, R. N. Systi, J. U. P. Corrêa, M. A. P. da Silva & Harry Ebert leg., DZ 39.984 ( DZUP, CPAC) , 1 female, 6-XI-2015, R. N. Systi, J. U. P. Corrêa, M. A. P. da Silva & Harry Ebert leg. ( CPAC) , 1 female, 6-XII-2015, R. N. Systi, J. U. P. Corrêa, M. A. P. da Silva & Harry Ebert leg. ( CPAC) ; Passo Fundo - 28°13›35.88”S, 52°24›13.05”W, 682m, 1 female, 10-VIII-2015, P. R. V. S. Pereira leg., DZ 39.967 , 1 male, 8-IX-2015, P. R. V. S. Pereira leg., DZ 37.890, 1 male, 8-X-2015, P. R. V. S. Pereira leg., DZ 39.988 ( DZUP) , 3 males, 1 female, 9-X-2015, P. R. V. S. Pereira leg. ( CPAC), DZ 39.914 , 2 females, 2 males, 11-X-2015, P. R. V. S. Pereira leg., DZ 39.905, DZ 39.915, DZ 39.904, DZ 39.907, 1 female, 2 males, 7-XI-2015, P. R. V. S. Pereira leg., DZ 39.987 ( DZUP, CPAC) , 1 male, 1 female, 9-XII-2015, P. R. V. S. Pereira leg., DZ 39.980 ( DZUP, CPAC) , 2 males, 1 female, 11-XII-2015, P. R. V. S. Pereira leg. ( CPAC) , 1 female, 5-I-2016, P.R. V.S. Pereira leg., DZ 39.982 ( DZUP) , 28°13’50.67”S, 52°24’17.04”W, 671m, 1 female, 9-X-2015, P. R. V. S. Pereira leg.( CPAC) , 1 female, 10-X-2015, P. R.V. S. Pereira leg., DZ 39.986 ( DZUP) , 3 males, 5-XI-2015, P. R. V. S. Pereira leg. ( CPAC), DZ 39.908 , DZ 39.909 ( DZUP) , 1 female, 1 male, 9-XI-2015, P. R. V. S. Pereira leg. ( CPAC), DZ 39.910 ( DZUP) , 2 females, 12-XII-2015, P. R. V. S. Pereira leg., DZ 39.912 ( DZUP, CPAC) , 1 female, 13-II-2016, P. R. V. S. Pereira leg., DZ 39.906, 1 male, 2 females, 11-II-2016, P. R. V. S. Pereira leg., DZ 39.983, DZ 39.981 ( DZUP, CPAC) , 1 male, 9-III-2016, P. R. V. S. Pereira leg.( CPAC) ; Vacaria - 1 male, 8-II-2009 ( CEUCS) , 1 female, 12-II-2009 ( CEUCS) , 1 female, 19-II-2009 ( CEUCS) , 1 male, 25-II-2009 ( CEUCS) .

Figures

Figure 1 Nomenclature adopted for wing venation and genitalia, based on Mythimna (P.) celiae sp. nov. a, fore and hindwing, scale bar = 10mm; b, male genitalia in ventral view; c, ampulla, digitus, and clasper in inner lateral view of the valva, with a scheme on the right side; d, uncus in posterior view; e, uncus in lateral view; f, fultura inferior (=juxta); g, aedeagus with everted vesica in lateral view; h-i, female genitalia in lateral and ventral views, respectively. Scale bars b-e, g-i= 1mm, f = 0.5mm.

Figure 12 Mythimna (P.) celiae sp. nov. a-b, male (DZ 39.913) in dorsal and ventral views; c-d, female (DZ 39.911) in dorsal and ventral views. Specimen deposited at the DZUP. Scale bar = 1cm.