Mesoleptobasis acuminata Santos 1961
Creators: name: Garrison, Rosser W.
name: Ellenrieder, Natalia Von
Publisher: name: Zenodo
Year: 2009
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Odonata
Coenagrionidae
Mesoleptobasis
Mesoleptobasis acuminata

description: Mesoleptobasis acuminata Santos 1961
Figs. 3 a, 4a, 5a, 7a, 9a, 10a, 12a, 14a, 15a, 16a, 17a, 18a, 21
Mesoleptobasis acuminata Santos 1961: 200 (in part, description of 3); — Davies & Tobin 1984: 77 (catalog); — Bridges 1994: VII.2 (catalog); — Steinmann 1997: 288 (catalog); — Tsuda 2000: 39 (catalog); — Lencioni 2006: 159 (notes and illustrations from original description); — Heckman 2008: 395 (key and reproduction of Santos 1961 illustrations).
Types. Holotype (locality unknown) in MNRJ (not examined but our illustrations compared and confirmed with holotype by J.M. Costa).
Specimens examined. Total: 3 3, 4 Ƥ. Peru, Loreto Department: 1 3, Explorama Lodge, 80 km NE of Iquitos on Amazon River at junction with Yanamono River (3°21'59"S, 72°47'56"W), 14 viii 1989, leg. S.W. Dunkle (RWG); 2 3, same but 13 viii 1989 (RWG); 2 Ƥ, same but 17 viii 1989 (RWG); 2 Ƥ, same but 31 viii 1989 (RWG); Explornapo Camp at junction of Sucusari River and Napo River, ca 160 km NE of Iquitos (3°16'33"S, 72°56'18"W), 27 viii 1989, leg. S.W. Dunkle (SWD).
Diagnosis. Male prothorax with a pair of lateral projections separated at base (Fig. 4 a; unique) and with acuminate apices directed antero-laterally; female prothorax lacking processes, with posterior margin slightly trilobate, with smoothly convex medial lobe slightly projected posteriorly beyond level of lateral lobes (Fig. 5 a; unique). Costal side of FW pt shorter than basal side (unique), its posterior margin strongly convex in male (Fig. 10 a), moderately convex in female (Fig. 12 a). CuA relatively long (shared with M. cyanolineata), extending one and a half to four cells distal to vein descending from subnodus in male, three to seven cells in female (Figs. 10 a, 12a). Genital ligula in ectal view with distal margin transverse and lateral sub-apical deep emarginations (Fig. 14 a; unique); in lateral view with a large triangular lateral lobe bearing a spine at its posterior base (Fig. 15 a; unique), and with an inconspicuous low latero-basal lobe (shared with M. cyanolineata). Posterior margin of male S10 recessed and with a medio-dorsal emargination, lacking posterolateral processes (Figs. 17 a, 18a; shared with M. cyanolineata). Male cercus subtriangular and attenuate dorsally with a membranous central area (Fig. 17 a; unique); in lateral view smoothly curved, with tip directed postero-ventrally (Fig. 18 b; shared with M. cantralli and M. incus); male paraproct about as high as half of S10 height at base in lateral view (Fig. 18 a; shared with M. cyanolineata); base of paraproct lacking a thumblike tubercle (Figs. 17 a, 18a; shared with M. cyanolineata and M. incus). Ovipositor surpassing tip of cerci for a distance shorter than length of cerci (Fig. 16 a; shared with M. cyanolineata and M. incus).
Dimensions. Males (n 3; mean in parenthesis): Hw 18.5–19.0 (18.8); abdomen 32.0–33.0 (32.7); total length 38.0–39.0 (38.3). Females (n 4): Hw 20.0–21.0 (20.6); abdomen 32.0–33.0 (32.25); total length 37.0–39.0 (38.0).
Remarks. Santos (1961) described this species from one male lacking locality data, which he designated as holotype, and two females from Porto Velho, Rondônia, Brazil. His description and figures of the holotype show no central membranous area on the dorsal surface of male cercus characteristic of the males from Peru we examined (Fig. 17 a). Unfortunately the holotype is incomplete and only its wings and hind legs remain (J.M. Costa pers. comm.). J.M. Costa kindly illustrated a pair of its wings for us, which had not been figured by Santos (1961). Her drawing (J.M. Costa in litt.) shows Fw Pt as less markedly convex along posterior margin than in the male we illustrated (Fig. 10 a), and Hw Pt rectangular, with costal and posterior sides slightly longer than basal and distal sides, rather than rhomboidal, with costal and posterior sides slightly shorter than basal and distal sides, as in our illustration (Fig. 10 a). The remainder of Santos’ (1961) description and illustrations of the holotype fully agree with males we ascribe to this species, and we consider them conspecific.
The females described by Santos (1961) as M. acuminata (allotype and paratype) are still in the MNRJ and not in the UMMZ as stated in the description (J.M. Costa pers. comm.). J.M. Costa sent us illustrations of one pair of wings, posterior lobe of pronotum, and S8-10 of female allotype (J.M. Costa in litt.). According to her drawings, pterostigmata are unmodified and rectangular and ovipositor is short, not surpassing tip of cerci.
The posterior lobe of the pronotum has lateral processes similar to those of males of M. acuminata, but the posterior margin between the lateral processes is bilobate lacking a medial lobe, rather than trilobate with a medial lobe as in the holotype and in our males (Fig. 4 a). We believe these females are not conspecific with the holotype male, and belong instead to an undescribed species (M. sp. in the key). We have females collected at the same locality as males we ascribe to M. acuminata, and they lack the long lateral prothoracic processes mentioned by Santos (1961). They have instead a smooth pronotum with slightly trilobate posterior margin (Fig. 5 a), similar to the trilobate margin of male (Fig. 4 a). They also differ by their ovipositor, which is longer (surpassing tip of cerci; Fig. 16 a) compared to the illustrations by Santos (1961, fig. 12) and J.M. Costa (in. litt.). We believe we have correctly associated the female sex of M. acuminata since it shares the characteristic modified pterostigma of male (unique for this species within Mesoleptobasis), although the modification is less pronounced than in male. The identity of the two females described by Santos (1961) as M. acuminata will remain uncertain until more of these females are found in association with males.
Distribution. Amazonian region of Peru (Fig. 21).
description: Published as part of Garrison, Rosser W. & Ellenrieder, Natalia Von, 2009, Redefinition of Mesoleptobasis Sjöstedt 1918 with the inclusion of Metaleptobasis cyanolineata (Wasscher 1998) comb. nov. and description of a new species, Mesoleptobasis elongata (Odonata: Coenagrionidae), pp. 47-68 in Zootaxa 2145 on pages 52-55, DOI: 10.5281/zenodo.188653