Oreiallagma, Ellenrieder, Natalia Von & Garrison, Rosser W., 2008

Ellenrieder, Natalia Von & Garrison, Rosser W., 2008, Oreiallagma gen. nov. with a redefinition of Cyanallagma Kennedy 1920 and Mesamphiagrion Kennedy 1920, and the description of M. dunklei sp. nov. and M. ecuatoriale sp. nov. from Ecuador (Odonata: Coenagrionidae), Zootaxa 1805, pp. 1-51 : 42-44

publication ID	https://doi.org/ 10.5281/zenodo.182666
DOI	https://doi.org/10.5281/zenodo.5691617
persistent identifier	https://treatment.plazi.org/id/03ED87D9-FF91-BE64-A9D1-A5AEFE066463
treatment provided by	Plazi
scientific name	Oreiallagma
status	gen. nov.

Treatment

Oreiallagma View in CoL gen. nov.

Figures 5 View FIGURE 5 ; 8; 25–29; 49–53; 85–94; 101; 104; 110–111

Type species: Cyanallagma thelkterion De Marmels 1997 by present designation.

Other species included: O. acutum ( Ris 1918) comb. nov., O. oreas ( Ris 1918) comb. nov., O. prothoracicum ( Kimmins 1945) comb. nov., and O. quadricolor ( Ris 1918) comb. nov..

Etymology: From ' oreios ' (Greek): of or from the mountains, and ' allagma ' (Greek): a neuter noun used for many damselfly names, allusion that was originally chosen by Charpentier (1840) to denote the possibility of mistaking coenagrionid genera with blue and black males with those of the genus Enallagma ( Fliedner 2006) . The name refers to the habitat of these species, which inhabit the Andean mountain range.

Generic characterization. Head. Color of dorsum dark brown to black with pale blue to olive postocular spots ( Fig. 5 View FIGURE 5 ), no pale postocular bar, rear of head pale. Frons rounded, occipital lobes not protruding posteriorly so that most posterior point of head is at eyes ( Fig. 5 View FIGURE 5 ).

Thorax. Medial lobe of posterior lobe of prothorax developed into caudally projected foliate plate ( Figs. 25–29 View FIGURES 25 – 29 ). Female mesostigmal plates rectangular and narrow with ratio of maximum width/length of less than 0.5 ( Fig. 28 View FIGURES 25 – 29 c). Pterothorax with dark mid-dorsal and humeral stripes, sometimes with a dark stripe over metapleural suture (absent in O. acutum , O. prothoracicum , and O. quadricolor ); with pale blue antehumeral stripe usually complete but interrupted distally in O. acutum and O. thelkterion ( Fig. 5 View FIGURE 5 ). Legs long with femur 1 always longer than distance between eyes at level of antennifer ( Fig. 5 View FIGURE 5 ; ratio = 1.08), tibial spurs shorter than or as long as distance between them, pretarsal claw with well developed supplementary tooth. Wings in most examined specimens smoky especially along costal area; CuP reaching CuPAA, proximal to hind margin of wing for a distance as long as CuP or shorter; vein descending from quadrangle not forming a straight line to wing margin ( Fig. 8 View FIGURE 8 ).

Abdomen. Color reddish-orange, black, and blue ( Fig. 5 View FIGURE 5 ); relatively long with a ratio of 4.4–6.5 to head plus thorax length. Genital ligula distal segment with one ( O. oreas and O. prothoracicum ) or two ( O. acutum , O. quadricolor , and O. thelkterion ) ental transverse folds and usually lacking inner process (inner process observed only in O. thelkterion , Fig. 49 View FIGURES 49 – 53 c), always with paired latero-apical lobes and usually with a pair of small accessory latero-medial lobes (absent in O. acutum ; Fig. 51 View FIGURES 49 – 53 ); second segment with unique wide paired latero-apical folds with sclerotized margins ( Figs. 49–53 View FIGURES 49 – 53 ). Postero-dorsal margin of male S10 recessed in dorsal view, with very slight ( O quadricolor , O. thelkterion ; Figs. 86 View FIGURES 85 – 89 ; 88) to more pronounced ( O. acutum , O. oreas , O. prothoracicum ; Figs. 85 View FIGURES 85 – 89 ; 87; 89) 'v'-shaped cleft lacking a lateral pair of tubercles. Male cercus with a long blade-like ventral process bent medio-anteriorly each of which converges with the one on opposite cercus before finally diverging at tip ( Figs. 85–94 View FIGURES 85 – 89 View FIGURES 90 – 94 ), and a dorsal process directed posteriorly of variable length: very short and subapical in O. oreas and O. quadricolor ( Figs. 93 View FIGURES 90 – 94 a–94a), long and apical in O. prothoracicum , O. thelkterion , and O. acutum ( Figs. 90 View FIGURES 90 – 94 a–92a). Patch of differentiated scalariform-like cuticle on posterior surface of male cercus present ( O. oreas , O. quadricolor , and O. prothoracicum ) or absent ( O. thelkterion and O. acutum ). Male paraproct with a dorsal branch ending on a sclerotized tip or ridge ( Figs. 90–94 View FIGURES 90 – 94 ). Female (known only for O. thelkterion and incompletely for O. quadricolor ) with vulvar spine on S8; ovipositor not reaching tips of cerci.

Generic diagnosis. Oreiallagma is unique among all genera of New World Coenagrionidae by the presence of a pair of wide latero-apical folds with sclerotized margins on second segment of genital ligula ( Figs. 49–53 View FIGURES 49 – 53 ), and by the forked male cercus combining a dorsal process and a long blade-like ventral process bent medio-anteriorly ( Figs. 85–94 View FIGURES 85 – 89 View FIGURES 90 – 94 ). Oreiallagma differs from Cyanallagma by having the rear of head surrounding occipital foramen pale (as in Fig. 1 View FIGURE 1 b) and by the male cercus having a dorsal process ( Figs. 85–94 View FIGURES 85 – 89 View FIGURES 90 – 94 ). Oreiallagma differs from Mesamphiagrion by having a forked male cercus combining a dorsal process and a long blade-like ventral process bent medio-anteriorly ( Figs. 85–94 View FIGURES 85 – 89 View FIGURES 90 – 94 ). Further differences are given in Table 2 View TABLE 2 . As mentioned under the previous two genera, the combination of a rounded frons, presence of pale postocular spots, a trilobate prothoracic posterior lobe, striped pterothorax, and male cerci provided with some kind of processes is shared among New World Coenagrionidae not only with Cyanallagma and Mesamphiagrion but also with Apanisagrion , Chrysobasis , Hesperagrion , Homeoura , some Ischnura species, Leptobasis , and Telagrion . Oreiallagma differs from all except Chrysobasis , Leptobasis , and Telagrion by its long abdomen in relation to length of head plus thorax with a ratio of over 4.4 versus less than 4.4. It differs from Chrysobasis , Leptobasis , and Telagrion by the presence of well developed supplementary teeth on pretarsal claws (vestigial or forming a right angular notch in the other three genera) and by female ovipositor not surpassing tip of cerci (extending beyond tip of cerci in other genera).

Remarks. Specimens are rare in collections, females are known for only two species, and all but two ( O. quadricolor and O. thelkterion ) have not been collected since their original descriptions. Species vary considerably in total length; their ranges from longest to shortest are: O. prothoracicum (= 55 mm), O. oreas and O. thelkterion (44–46 mm), O. quadricolor (40 mm), and O. acutum (37 mm). If breeding biology for the genus mirrors that for O. quadricolor (within bromeliads in high elevation forest areas), we suspect future collecting in these forest zones will yield more specimens, and intraspecific adult size variation will be considerable due to differences in space and food availability within phytotelmata habitats.

Distribution. Narrow mountainous corridor in Andes from Venezuela to Bolivia, from 800 to 2300 m above sea level ( Fig. 104 View FIGURE 104 ).