Machadagrion garbei ( Santos, 1961 )

Vilela, Diogo Silva, Lencioni, Frederico Augusto De Atayde, Furieri, Karina Schmidt & Santos, Jean Carlos, 2022, The rediscovery of Machadagrion garbei (Santos, 1961) (Odonata: Coenagrionidae) with notes on the hitherto unknown female, Zootaxa 5124 (3), pp. 391-396 : 392-394

Machadagrion garbei ( Santos, 1961)

( Figures 1−3 )

Leptagrion garbei Santos 1961: 360 , Figures 5–8 (Description of male, illustrations of appendages in lateral and dorsal views, pterostigma of fore wing, male prothorax in dorsal view); Santos 1979: 170 (compared with L. bocainense Santos, 1979 ); Davies & Tobin 1984: 82 (data on publication and distribution); Machado & Costa 1990: 301 (data on publication and distribution); Bridges 1994: (VII) 96 (data on publication, type depository, type locality and references); Costa & Mascarenhas 1998: 6 (data on types); Costa & Garrison 2001: 383, Figures: 11a, 11c, 32b (key to Brazilian species of Leptagrion , illustration of appendages in lateral and dorsal views, male forewing pterostigma); Lencioni 2006: 148, Figures 89A–89D (data on description, type locality, type deposition, distribution, and larval description, illustration of appendages in lateral and dorsal views, male prothorax in dorsal view, male hind wing pterostigma); Lencioni 2022: 90−91 (transference from Leptagrion Selys to Machadagrion Lencioni , generic characterization, distribution).

Material examined. 9♂♂ and 1♀. 2♂♂ Brazil, Bahia, Camaçari, Barra do Jacuípe, Condomínio Planeta Água , (12.7205 S, 38.1386 W), 31.vii.2006, Freire, L.S. and Ferreira, P.A. leg. ( FAAL) ; 1♂, same data but 11.ii.2007 ; 6♂♂ and 1♀ (in tandem) Brazil, Sergipe, Areia Branca, Serra de Itabaiana National Park , (10.7517 S, 37.3415 W, 179 m asl), 3.ii.2021, J.C. Santos leg. ( UFS) .

Morphology of the female. Head ( Figure 1a ). Labium, labrum, and postclypeus blue; base of mandibles and genae pale colored, apex of mandibles black; antefrons and postfrons dark brown; remainder of head dark colored, except for two quadrangular pale postocular spots. Rear of head pale.

Thorax ( Figures 1a , 2 a−b). Anterior lobe of prothorax light blue dorsally, dark blue laterally with pale apical areas; medial lobe brown dorsally, light blue laterally; posterior lobe light blue laterally, brown medially, widest at base with slight lateral projections, slight medial concavity, and roughly trapezoidal shape. Medial portion of mesepisternum brown, remainder with a blue stripe extending up to the mesopleural suture; mesinfraepisternum light brown, with a blue basal coloration; mesepimeron mostly orange, bluish basally; remainder of pterothorax pale colored; legs mostly pale.

Wings ( Figure 1a ). Hyaline; Pt light brown, quadrangular, with pale borders, overlying the space of one cell; 10 Px in FW and HW; RP1 originates at Px 7 in all wings.

Abdomen ( Figures 1a , 2c ). S1−2 dark brown dorsally, pale blue laterally and ventrally; S2 with an apical dark brown ring; S3−6 mostly brown with pale basal and apical rings; S7 dark brown; S8 blue dorsally, dark brown laterally; S9 with a blue dorsal posterior spot, remainder brown; S10 blue dorsally, brown laterally; appendages brown with black apex; genital valves brown, styli black.

Measurements. FW: 20.5; HW: 19.5; AL: 38.9; TL: 46.7.

Differential diagnosis. Unfortunately, we could not perform a comparison of our specimens of M. garbei with the type material, as it was lost in the big fire of 2018 at the National Museum of the Federal University of Rio de Janeiro. However, we had access to a bona fide specimen of this taxon, housed at FAAL, collected in 2006 and compared with the original series. Machadagrion garbei ( Figures 1 a−b) is a species morphologically close to M. cyanostigma ( Machado, 2012) and M. dardanoi (Santos, 1968) according to male hind lobe of prothorax and cercus ( Figures 3 a−d) and female hind lobe of prothorax ( Figures 2 a−b). In M. garbei , the ventral “C”-shaped branch ( Fig. 3c ) is subequal to dorsal branch (longer than dorsal branch in M. dardanoi see Lencioni 2022); the dorsal branch of cercus in M. garbei ( Fig. 3c ) is similar to M. cyanostigma , but is truncated in the latter (see Lencioni 2022). Additionally, M. cyanostigma is the only species with a blue pterostigma ( Machado 2012), thus it can be easily separated from other congeners. The female of M. garbei differs from those Machadagrion females by the following combination of characters (other species on parenthesis): abdomen length> 38 mm (22 mm in M. dardanoi ; 31 mm in M. cyanostigma ), hind lobe of prothorax ( Figures 2 a−b) widest at base, with slight lateral projections, slight medial concavity, and roughly trapezoidal shape (narrower at base on M. dardanoi ; roughly trapezoidal, no medial concavity, and without lateral projections on M. cyanostigma ).

Final remarks. The IUCN red list assessors had classified M. garbei as Data Deficient, and stated: “This poorly known species was collected for the last time in 1963 ( Costa & Garrison 2001). Nothing else is known about distribution and ecology” ( Vilela & Guillermo-Ferreira 2021). Unfortunately, the lack of distributional data for M. garbei is not an exception for Odonata species, as it is the case for 28% of all the assessed taxa ( IUCN 2021). Until now, M. garbei was known to occur in the states of Bahia and Alagoas ( Costa & Garrison 2001), and in the present study we expand its record to Sergipe state, which is located between the two states mentioned before ( Figure 4 ). Even if the distribution of M. garbei falls within the expected range of occurrence of the species, our discovery proves that the species is still thriving on their natural habitats, including a protected area. Thus, we expect that the rediscovery of this poorly known species to be an essential step to establish strategies for its protection.

Figures

FIGURE 1. Machadagrion garbei (Santos, 1961): lateral view of habitus of female (a) and male (b), both from Sergipe state, Brazil.

FIGURE 2. Machadagrion garbei (Santos, 1961), female: dorsal (a) and lateral (b) views of prothoracic hind lobe; S8−10 (c).

FIGURE 3. Machadagrion garbei (Santos, 1961), male: lateral (a) and dorsal (b) views of prothorax; lateral (c) and dorsal (d) views of anal appendages.

FIGURE 4. Currently known distributional range of Machadagrion garbei (Santos, 1961).