Lestes secula, May, 1993

May, M. L., 1993, Lestes secula, a new species of damselfly (Odonata: Zygoptera: Lestidae) from Panama, J. New York Entomol. Soc. 101, pp. 410-416 : 411-414

Lestes secula , new species

Fig.1 A-F Material examined.- Holotype: ♂ (#1), Panama, Area del Canal, Barro Colorado Island, seasonal pond at Standley Trail marker 5 , 28 March 1974, coll. by M. L. May, IORI. Allotype: ♀ (#2), same data as holotype except 19 Ŧanuary 1974. Partypes: 1 ♂ (#3), Panama, Prov . Panama, Pacora , 24 December 1950, coll. by R. B. Cumming, FSCA; 1 ♂ (#4), 1 ♀ (#5), same data as holotype except 9 Feb. 1972, teneral specimens preserved in alcohol, MLM; 1 ♂ (#6), 2 ♀ (#' s 7, 8), same data as holotype except collected as larvae on 15 September 1974 (♂ emerged 22 Sept., ♀ 's emerged 20 and 23 Sept.), preserved in alcohol, FSCA .

Etymology. - Secula is the Latin noun for sickle, or scythe, referring to the shape of the male cerci.

Diagnosis. -A species of moderate size and stature, dark and not strongly metallic or pruinose; the posterior surface ofthe head is mostly black, the medial mesepistemal dark stripe at least?/2 width of that sclerite, and distinct dark markings are present above and below the metapleural carinae and on the thoracic venter ( Fig. 1F ). The shape of the male cerci is unique; the paraprocts are unusually short and stout ( Fig. 1A, B ). The ventral margin of the ovipositor is distinctly concave and the basal plate rounded ( Fig. 1E ). Males of L. secula resemble L. tenuatus in the form of their paraprocts and in size

and general coloration but are usually darker insects with wider and less brightly metallic mesepisternal stripes (dark thoracic areas of some old male L. tenuatus may be as extensive as in L. secula , however), a more extensive dark pattern on the metathoracic venter, and the rear of the head dark. They ordinarily are easily dis tinguished by the absence of a basal tooth along the medial margin of the cerci, although this tooth may occasionally be blunt and lobe-like in L. tenuatus ( Ŧohnson, 1975) . Females are very similar to L. tenuatus in the form of the ovipositor and the slightly flavescent wings but are stockier (in L. tenuatus abdominal segment 3 is at least 6 times as long as its height at midlength) and differ in the same color characters.

Both sexes of L. secula also are somewhat like L. henshawi , a species not recorded from Panama but expected to occur (Tsuda, 199 1). Lestes henshawi is an appreciably larger species, however (hindwing longer than 25 mm, abdomen longer than 36 mm in males, 33 mm in females), with the pronotum largely black, black areas of the pterothorax lacking greenish reflections, and pale areas of the pterothorax contrasting sharply with the black and apparently not becoming brown and obscure. Like L. tenuatus , male L. henshawi have a distinct basal tooth on the inner edge of the cerci. The ovipositor of female L. henshawi resembles both L. secula and L. tenuatus in having a rounded basal plate but differs from both those species in that the ventral margins of the third valvulae are nearly straight, not distinctly concave.

The absence, as in L. secula , of a basal cercal tooth is uncommon among male Lestes and mostly occurs in species with a distinct declivity toward the apex of the cerci. An exception is L. pictus Hagen in Selys. In this South American species, however, the medial shelf of each cercus is wider apically ( Calvert, 1909; Muzon, pers. comm., 1991) than in L. secula , and in the male syntype (which now lacks its terminal abdominal segments; pers. obs., 1988) the rear of the head is pale, and the dorsum of abdominal segment 2 has a wider, triangular pale stripe. The female syntype also has the rear of the head pale and the ventral margin of the ovipositor straight; a female in the Carnegie Museum (Pittsburgh, PA) has the ovipositor barely concave, with the basal plate right-angulate.

Holotype.- Abdomen broken between segments 4 and 5, both hind tarsi broken off, subapical tear in both forewings.

Head with labrum light blue with narrow brown margin and small mediobasal spot. Genae and outer surface of mandible ivory with slight bluish cast. Clypeus broadly brown along clypeolabral and epistomal sutures, black between. Antefrons brown ventrally, becoming black above; remainder of epicranium black with slight metallic greenish reflections except for small brown areas just lateral to lateral ocelli and on occipital ridge. Antennae black to dark brown with tan anterior stripe on 2 basal segments, ocelli brown, eyes grey (probably bluish in life). Rear of head black except small yellowish central area, mouthparts tan with apexes of mandibles and maxillae black.

Prothorax brown with small, geminate black spot on middle lobe; slightly pruinose dorsally, heavily so on pleura. Pterothorax with middorsal carina and narrow flanking stripes, antealar ridge and sinus, and tergal sclerites brown. Mesepisterna each with black stripe, showing metallic greenish reflections, extending their full length and gradually widening from about?/2 width of sclerite anteriorly to 2/3 width at posterior end. Laterally and ventrally, thorax largely brown, slightly darker on center of mesepi meron, yellowish tan on ventral mesinfraepisternum, anterior metepisternum, lateral metepimeron, and venter; pattern of dark ventral and ventrolateral markings like Figure 1F but nearly obscured along midline by pruinosity. Also heavily pruinose

on coxae and anterior tergal sclerites, lightly so along metapleural and interpleural sutures. Legs tan, brown on extensor surfaces of femora, black on internal and external angles and distal ends of femora, flexor surfaces of tibiae, and most of tarsi. Wings hyaline, veins and pterostigmata black to dark brown.

Abdomen with terga of segments 1-8 black with slight metallic greenish reflections dorsally except grey on basal 1/3 and distal 1/6 of segment 1, tan along diffuse, narrow median line on 2, extremely narrow hairline on 3 and 4, and narrow, medially interrupted basal rings on 3-8. Tergites tan ventrolaterally except for black apical annulus on each and black ventral margin of 1, marginal spot of 2, and edges of hamules. Segments 9 and 10 dark red-brown, dorsal apex of 10 black; caudal ap pendages mostly black. Sternum of segment 1 tan with median black stripe, 2-7 black, 8 and 9 each brown with median black line. Third abdominal segment 10 times as long as its height at midlength, 2.5 times as long as segment 2. Cerci 1.12 mm, lacking prominent teeth along medial edges, each with shelf-like medial dilation along distal 4/5 that is widest near base and gradually tapers to apex; paraprocts 0.66 mm, slightly upcurved, with terminal tuft of setae ( Fig. 1A, B ). Penis not extruded but presumably as in Figure 1C, D .

Measurements: Total length-37.0, abdomen-29.0, hindwing-21.0.

Allotype.-Left prothoracic leg broken at trochanter, abdominal segment 9 in dented dorsally.

Head and prothorax as in holotype except labrum dull, dark grey. Pterothorax with mesepisternum similar to holotype but middorsal carina darker and less distinct from black stripe, antealar ridge and sinus dark. Mesepimeron dark brown with black streak about 2/3 its width along central 3/5. Mesinfraepisternum black on dorsal 1/2, yellowish ventrad. Metapleura and venter yellowish-tan with dark line along each metapleural sulcus and along anterodorsal margins of metinfraepisternum. Dark markings of venter similar to holotype but much less obscured by pruinosity. Legs and wings as in holotype except wing membranes faintly flavescent.

Abdominal segments 1-7 marked much as in holotype but dark areas generally more extensive. Pale ventrolateral areas of segments 1 and 2 with distinct greenish grey tint, those of 3-7 darker than in holotype. Segments 8-10 entirely dark brown to black except small, ventrolateral tan markings on 8. Third abdominal segment 5 times as long as its height at midlength, 2.1 times as long as segment 2. Ovipositor 2.25 mm, with ventral margin of valvula 3 distinctly concave near midlength, basal plate rounded ( Fig. 1E ).

Measurements: Total length-37.5, abdomen-29.5, hindwing-22.0.

Variation among paratypes.-Male from Pacora like holotype except generally darker, hence probably older. Postclypeus entirely dark. Pterothorax marked as in allotype except lateral dark areas more extensive and ventrolateral margins darker; venter with less pruinosity, more extensive dark marking than holotype. Abdomen with middorsal lines obsolete, lateral areas of segment 1 entirely margined with black. Penis shown in Figure 1C, D. Total length- 38.0, abdomen-30.0, hindwing-22.0.

The teneral and reared specimens, in alcohol, have very faintly developed color patterns. They appear similar to those of the holotype and allotype, except with the mesepisternal dark stripe slightly narrower, probably a function of age. Structurally they seem identical. Measurements are not given because of the probability of dis tortion of the soft cuticle.

Notes.- Like many Lestes , this species inhabits seasonal ponds with abundant bottom litter and no fish. The type locality is typically dry from about February to May or Ŧune. It is in old-growth, seasonal moist forest, receives sunlight only inter mittently except at midday, and has little or no rooted aquatic vegetation. Seemingly mature L. secula could be found throughout most of the year, but I observed re productive activity only during the wet season. Possibly this species, like a number of other tropical dragonflies, passes the dry season in adult diapause. Other Odonata collected at the type locality included Miocora peraltica Calvert (probably not breed ing), Metaleptobasis westfalli Cumming, Neoerythromma cultellatum (Selys), Gyna cantha gracilis (Burmeister), G. tibiata Karsch, Triacanthagyna satyrus (Martin) , Anatya normalis Calvert , Cannaphila insularis Kirby, Erythrodiplaxfervida (Erich son), Micrathyria atra (Martin) , and Perithemis mooma Kirby. In Panama, L. ten uatus Rambur is common in similar habitats but was not collected with L. secula .

Figures

Fig. 1. Lestes secula spec. nov. A-male caudal appendages, dorsal view; B-male caudal appendages, lateral view, right appendages omitted; C-head and distal shaft of penis, ventral view; D-head and distal shaft of penis, lateral view; E-apex of female abdomen, lateral view (bp-basal plate of ovipositor); F-diagram of color pattern on ventral metathorax. Scale bar - 0.5 mm for A, B; 0.3 mm for C, D; 1.0 mm for E.