Erythrodiplax nataliae sp. nov., a new species for the state of Mato Grosso, Brazil

: Erythrodiplax nataliae sp. nov. (5 males), collected in Vereda wetlands (a unique Neotropical savanna environment) in Mato Grosso, Brazil is described and illustrated. The new species fi ts in Borror’s Juliana Group, and can be distinguished from other species by the combination of the following traits: blue pruinosity on thorax (more dense dorsally); sides of the pterothorax yellowish, darkening dorsally; face ivory, dorsally black with a metallic blue refl ection; wings hyaline with a small basal brown spot; vesica spermalis with long lateral lobes, enclosing the median process and median process elongated with a pair of conspicuous rectangular and elongated lateral lobes, with a middle dorso-ventral furrow.


INTRODUCTION
The genus Erythrodiplax Brauer is the most speciose libellulid genus in the New World, currently comprising 58 species distributed from southern Canada to 45° S in Patagonia (Garrison et al. 2006, del Palacio & Muzón 2019. Their species are inhabitants of different types of wetlands, and many of them can be abundant in temporary ponds, marshes and stream pools.
Since the last revision of this genus (Borror 1942) eight new species has been described from the Caribbean (Jamaica and Cuba), Central America (Costa Rica) and South America (Venezuela and Brazil) (Borror 1957, Guillermo-Ferreira et al. 2016, Haber et al. 2015, Machado et al. 1995, Dos Santos 1946, 1956, Needham et al. 2000. Borror (1942Borror ( , 1957 proposed 13 species groups based mainly on the vesica spermalis morphology, including the monotypic Juliana, characterized bythe presence of big lateral lobes in the median process. The aim of this work to describe a new species of Erythrodiplax belonging to the Juliana Group from the state of Mato Grosso, Brazil and to provide a modification of the specific key proposed by Borror (1942).
The ZooBank Life Science Identifi er (LSID) of this publication is: urn:lsid:zoobank.org pub:C53D055B-182E-492E-888D-DA6C0290E849. All drawings were made with the aid of a Zeiss Discovery V20 stereomicroscope coupled to a digital camera Axio CAM ICc5 and the use of graphic design software and photo editor.

MATERIALS AND METHODS
Photographs were taken with the aid of a digital camera setup on a stereomicroscope and the microphotographies were taken with the aid of a Scanning Electron Microscope (SEM) JEOL JSM-T100. Specimen preparation for microphotographies follows the method proposed by del Palacio et al. 2017. Maps with distributional records were where prepared with the use of the free software Quantum Gis.
Male holotype description (Figures 1-4) Head. Ivory, except dorsal margin of the frons black with metallic blue reflections; labrum white; vertex basally ivory to black, metallic blue dorsally, without tubercles ( Figure 1b).
Legs. (Figure 2b). Coxae and trochanters brown; femora and tarsi light brown, with flexor margin black. Femur III with 12 spines, last spine two times as long as penultimate one.
Wings ( Figure 2c). Hyaline, veins black, pterostigma light brown; FW with a proximal faint dark spot between C and R (in one specimen almost absent); HW with a small basal spot reaching basal half of median space. FW: 9 ½ antenodals; 10 post nodals; triangle 2-celled; subtriangle 3-celled; discoidal field starting with three rows of cells, finishing with 5; one bridge crossvein. HW: 8 antenodals; 9 postnodals; triangle free; CuP origin separated from anal angle of triangle.
Vesica spermalis (Figures 3-4). Hood developed as two processes; apical tubercle absent but a semicircular membranous area can be observed in its position (although it doesn't inflates); median lobe small, (Figures 5a, b); lateral lobes long, narrowing distally and enclosing the median process, meeting each other dorsally ( Figures 4a, b). Median process elongated with a pair of conspicuous rectangular and elongated lateral lobes ("U" shaped in frontal view) and with a middle dorso-ventral furrow (Figure 3c). Whether they are in fact a pair of internal lobes it is uncertain (Figures 4a, b). The apical lobe has several rows of bristles; posterior lobe present but greatly reduced.

Paratypes
Thorax. Pterothorax greenish with pruinosity covering most of the thorax.

Ecological data
The specimens were collected in the "Veredas" (Figure 5), one of the 11 phytophysiognomies found in the "Bioma Cerrado" of the "Planalto Central Brasileiro" (Ribeiro & Walter 2008

Diagnosis
Erythrodiplax nataliae n. sp. fits in the Juliana Group proposed by Borror (1942) because it shares its conspicuous elongated IV segment of the vesica spermalis, presence of lateral lobes at the median process, small posterior lobe and lack of an apical tubercle.
Erythrodiplax nataliae differs from E. juliana in the brownish, not uniformly colored body color pattern (uniformly black in E. juliana); anterior margin of the frons without a ridge (present in E. juliana) and by the shape of the lateral lobes of the vesica spermalis (short in E. juliana) as shown in Figures 4c-d. This species color pattern resembles Erythrodiplax pallida and E. ana due to its bluish pruinosity alongside the thorax and the whitish frons. From E. pallida it can be distinguished by its frons entirely white (dorsally black in E. nataliae), femora mostly black or dark brown (flexor margin black, remainder yellowish in E. nataliae), cerci dark red (ivory in E. nataliae), HW with a medium sized basal spot (small or absent in E. nataliae), posterior lobe of the vesical spermalis with rows of setae (without setae in E. nataliae); from E. ana by its metallic blue vertex (ivory and dorsally black in E. nataliae), wing tips with a brown tinged (hyaline in E. nataliae); hammuli external arm bigger than inner (smaller or equal in E. nataliae).
The vesica spermalis shows many differences between both species and E. nataliae, such as   the median process without lobes (with in E. nataliae), lateral lobes not meeting dorsally (as described before in E. nataliae), small to medium size posterior lobe (reduced in E. nataliae).

Modification of Borror'skey (1942) for the genus Erythrodiplax
Erythrodiplax nataliae run to couplet 26, this couplet was already amended by del Palacio & Muzón (2019) to include E. chromoptera, so a modification in order to include males of the species should be added to include E. nataliae: 26. Median process of the penis (=vesica spermalis) bilobed, the lobes extending ventrad (Figures 172-174 A. Lateral lobes of median process triangular on lateral view; body black (except for the cerci); frons black, with an anterior ridge……...……juliana A'. Lateral lobes of median process rectangular on lateral view; body light brown with blue pruinosity, except for the cerci;frons whitish, without an anterior ridge……………nataliae 26'. Median process of the penis, when erect, bilobed at apex of the median process, extending dorsally; frons not flattened, black and vertex biturbeculated; median process extending beyond apex of lateral lobes; wings with basal extending up to the 3rd antenodal and at least the triangle, with a distinct patter as shown in Figure 1b…………