Cordulegaster sarracenia

Abbott, John C. & Hibbitts, Troy D., 2011, Cordulegaster sarracenia, n. sp. (Odonata: Cordulegastridae) from east Texas and western Louisiana, with a key to adult Cordulegastridae of the New World, Zootaxa 2899, pp. 60-68 : 64-68

Affinities of Cordulegaster sarracenia with other species

Among the New World Cordulegastridae , C. sarracenia appears to be most closely related to C. sayi , though the two species differ in both thoracic and abdominal color pattern. C. sarracenia fits well in the C. diastatops group, sharing a unique combination of characters including: male epiproct beyond S10 wider than long, male cerci separated basally by more than 2x basal width of cerci, male cerci inflated beyond ventral spine, compound eyes distinctly separated dorsally, posterior surface of eyes tumid, and vulvar lamina extending approximately 1/2 its length beyond cerci.

Lohmann (1992) erected the genus Archegaster for C. sayi and differentiated it from Zoraena using eight characters ( Table 1). Cordulegaster sarracenia shares a combination of characters with both these genera, which provides support for the collapse of Archegaster into Zoraena . While the characters distinguishing Zoraena seem consistent, I have followed the general convention in North America and not recognized its generic status.

Zoraena Archegaster # of pairs of spots dorsally on abdomen 1 2

Hind margin of Hw with attenuation at R4 yes no

Position of mouthparts prognathic orthognathic Occiput shape triangular trapezoidal Width of compound eyes/width of frons edge>2 <2

Distance of ventromedial spine between basal spine and cercus tip 1/2–2/5 1/4

Cerci with dilation at apex yes no

Color of costa brown yellow

Figures 7–14 illustrate the differences in the cerci and epiproct within the C. diastatops group. Cordulegaster sayi ( Figs. 11–12 ) and C. sarracenia ( Figs. 1–2 ) stand out in this group as having longer, narrower cerci with a slipper-shaped upturn at their tip when viewed laterally. In C. sarracenia , the epiproct does not extend to the medial dilation of the cerci in dorsal view. In dorsal view, the ratio of the length of the cerci (taken at their longest point) to the length of the epiproct at its middle is greater than 1.8 for C. bilienata , C. diastatops , and C. talaria , and less than 1.8 for C. sayi and C. sarracenia . It should be noted that Fraser’s (1929) illustrations of the lectotype of C. sayi in the British Museum look different from more current illustrations in later works, with the cerci appearing much shorter and wider, especially towards the apex in lateral view.

Tennessen (2004) compared four characters for the diastatops group. Using his data, we included measurements for the same characters for the two male C. sarracenia ( Table 2). The average distance between the cercal spines, 0.56 mm, fell within the range found for C. bilineata and C. diastatops but was larger than that for C. sayi and smaller than for C. talaria . The average distal width of the epiproct, 1.80 mm, was essentially the same as that of C. talaria and within the range found for the other three species. Pilgrim et al. (2002) found a significant difference between C. bilineata and C. diastatops in the ratio of the epiproct distal width and cercus length; however, Tennessen’s (2004) analysis showed a significant difference only between C. talaria and the other three species. For C. sarracenia this average ratio, 1.1, was the same as for C. talaria . The mean width of the metepimeral stripe, 0.96 mm, was less than that of the four other species, but within the range of C. bilineata and C. sayi .

The paraprocts are enlarged and distinct in male Cordulegaster . Examination of these structures ventrally initially indicated promise for interspecific differences, but interspecific variation renders this character unreliable.

Key to New World Cordulegaster adults (adapted from Needham et al. 2000)

1. Occiput raised well above eyes and forming a conical protuberance; S3–7 with middorsal spear-shaped spots........ obliqua

1’. Occiput at most raised above eyes and evenly convex; S3–7 with bands or paired spots.............................. 2

2(1’). Eyes separated dorsally; female ovipositor projecting beyond tip of S10 for 1/3 or less its length....................... 3

2’. Eyes touching at one point; female ovipositor extending beyond tip of S10 for at least 1/2 its length.................... 7

3(2). S2–8 with bands of yellow that may be interrupted by brown middorsal carina; mes- and metepimeral thoracic stripes dis- tinctly paler than dorsal thoracic stripes.................................................................... 4

3’. S2–8 with paired elongated spots or stripes; lateral thoracic stripes same color as dorsal thoracic stripes................. 5

4(3). Ventromedial spine of male cercus at 1/4 length from base; S2–8 with bands continuous middorsally; metepisternum with dis- tinct reddish or purplish stripe.......................................................................... sayi

4’. Ventromedial spine of male cercus at 1/3 length from base; S2–8 with bands interrupted middorsally by brown middorsal carina; metepisternum without distinct stripe........................................................ sarracenia

5(3’). Distance between tips of ventral cercal spines in males ≥ 0.76 mm; crest of occiput, in direct anterior view, straight to slightly convex in females................................................................................ talaria

5’. Distance between tips of ventral cercal spines in males ≤ 0.72 mm; crest of occiput, in direct anterior view, distinctly convex in

females or if only slightly convex, then small rounded yellow spot on S4 and metepimeral stripe <1.4 mm wide.......... 6 6(5’). Anteclypeus and ventral margin of postclypeus uniformly dark brown or black; legs dark, often black; apical width of male epiproct approximately 1.3 times length of cerci...................................................... diastatops

6’. Anteclypeus light brown and ventral margin of postclypeus largely yellow; legs brown; apical width of male epiproct about equal to length of cerci........................................................................... bilineata

7(2’). S2–8 with paired yellow dorsolateral spots; antefrons predominately pale......................................... 8

7’. S2–8 with bands of yellow; antefrons dark brown............................................................ 9

8(7). Entire postfrons distinctly darker than antefrons; forewing with 3 cubito-anal crossveins...................... maculata

8’. Entire postfrons not darker than antefrons (antefrons concolorous in C. d. deserticola or streaked with brown or black in C. d. dorsalis); forewing usually with 2 cubito-anal crossveins................................................ dorsalis

9(7’). Postfrons brown................................................................................. godmani

9’. Postfrons pale at least medially.......................................................................... 10

10(9’). S8–9 with yellow bands interrupted middorsally by more than width of middorsal carina; rear of head largely brown or black; forewing with 3–4, rarely 2, cubito-anal crossveins...................................................... erronea

10’. S8–9 with yellow bands not interrupted middorsally, or if so by no more than width of middorsal carina; rear of head yellow; forewing with 2 cubito-anal crossveins............................................................... diadema

C. diastatops , C. sayi , and C. talaria taken from Tennessen (2004). Measurements in mm.

Character Species n Mean Range

Cercus spine gap C. bilineata 77 0.64 0.52–0.73 C. diastatops 32 0.65 0.54–0.71 C. sayi 40 0.46 0.36–0.52 C. sarracenia 8 0.56 0.46–0.62 C. talaria 19 0.83 0.77–0.89

Epiproct width C. bilineata 77 1.76 1.57–1.99 C. diastatops 32 2.05 1.77–2.24 C. sayi 40 1.93 1.77–2.14 C. sarracenia 8 1.80 1.70–1.96 C. talaria 19 1.81 1.69–1.91

Epiproct width/cercus length C. bilineata 75 0.99 0.87–1.16 C. diastatops 32 1.23 1.12–1.40 C. sayi 40 0.98 0.89–1.11 C. sarracenia 8 1.11 0.99–1.23 C. talaria 19 1.10 1.02–1.16

Metepimeral stripe width C. bilineata 77 1.06 0.82–1.31 C. diastatops 32 1.52 1.27–1.80 C. sayi 40 1.05 0.90–1.23 C. sarracenia 8 0.96 0.85–1.10 C. talaria 19 1.59 1.44–1.68

Habitat and biology. The recent discovery of this species resulted in a period of little more than one week of fieldwork in 2010 and three weeks in 2011 before its flight season was over. Its known flight season (based on photos and specimens) is 15 March – 29 April. All individuals observed to date were associated with bogs supporting the pitcher plant Sarracenia alata. All of these bogs have small, spring-fed seeps running through them. This restricted habitat, along with the discovery of this species only recently, suggests its preference for these bogs as a breeding habitat. Carle (1983) states that members of the C. diastatops group are typically found near spring runs and small streams. His observations of the behavior of the group, including males perching obliquely at ca. 45° on sunlit stems approximately 10–70 cm above ground, are also consistent with observations for this species. Other species of North American Cordulegaster are typically found patrolling closer to the water at distances less than 30 cm.

Males and females have been observed flying along ridge tops some distance from water. Oviposition has not been observed in C. sarracenia , but members of the C. diastatops group are known to hover with the body at 60° from the water surface between thrusts of the ovipositor ( Carle 1983).

Nymphs of various instars and one exuviae were collected in 2011. They are largely found in hillside seepages. Tachopteryx thoreyi nymphs were collected alongside them at one location.

Distribution and Conservation Status. The new species is known from only six different localities in five counties and one parish in southeast Texas and western Lousiana (Anderson, Angelina, Jasper, Newton and Tyler Counties in Texas and Natchitoches Parish in Louisiana). Records from Anderson and Tyler counties are based on photographs. These points are separated by 275 km at the farthest, but all are associated with bogs containing the Pale Pitcher Plant or Yellow Trumpet ( Sarracenia alata Wood).

Currently C. sarracenia is restricted to bogs where pitcher plants reside, which is cause for concern. In many areas such as the Big Thicket, these bogs are becoming rare because they are being ditched for drainage ( Ajilvsgi 1979). The distribution of S. alata is in southeastern United States adjacent to the Gulf of Mexico and includes Mississippi and Alabama in addition to Texas and Louisiana. Because Cordulegaster sarracenia has only recently been discovered, it should be considered Data Deficient in any Red List classification.

Figures

FIGURES 7 – 14. Lateral (left) and dorsal (right) views of the cerci and epiproct for members of the C. diastatops group. 7 – 8. C. bilineata. 9 – 10. C. diastatops. 11 – 12. C. sayi. 13 – 14. C. talaria.

FIGURES 1 – 5. Cordulegaster sarracenia. 1 – 4. Holotype. (1) lateral view of cerci, epiproct and paraproct; (2) dorsal view of cerci and epiproct; (3) lateral view; (4) dorsal view of S 4 – 10. (5). Lateral view of allotype.