Argia nataliae Garrison, 2019

Garrison, Rosser W., 2019, Argia nataliae n. sp. from Colombia (Odonata: Coenagrionidae), Zootaxa 4590 (4), pp. 477-486 : 478-484

Argia nataliae Garrison , n. sp.

Figs. 1 (head, anterior view ♂), 2 (head, anterior view ♀), 4 (head, thorax, S1– 4 ♂), 8 (head, thorax, S1– 4 ♀), 10–11 (S1–2, dorsolateral view ♂), 12 (S7–10, lateral view ♂), 13 (S7–10, dorsolateral view ♂), 16 (S7–10, lateral view ♀), 19 (genital ligula), 20 (mesostigmal plates ♀), 22 (appendages), 24 (map).

Etymology. Named nataliae (Latinized name) in honor of my dear wife and eminent Odonatologist, Natalia von Ellenrieder in recognition of her valuable contributions to the knowledge of Neotropical Odonata and for her continuing aid and help in our work on this genus.

Specimens examined. 9 ♂ ♂, 23♀ ♀. Types . Holotype ♂: COLOMBIA, Antioquia Department, [Estación] Cristalina, about. 28 km west of Puerto Berrio , ca. 6.4116° N, 74.5773 W, ca. 320m., 16 ii 1917, Jesse Hunter & Edward Bruce Williamson leg. ( UMMZ) ; Paratypes 6 ♂ ♂, 14 ♀ ♀: same data but 12 ii 1917 ; 1 ♂, 3 ♀ ♀: same data but 16 ii 1917 ; 1 ♂, 5 ♀♀; same data but 20 ii 1917 ( CSCA, UMMZ, RWG)

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A largely dark species lacking postocular spots, with metallic middorsal and humeral stripes, and, in the male, unique caudal appendage morphology.

Description of male holotype. Head (as in Fig. 1 , Fig. 4 ): Labrum, postclypeus and antefrons shining black, genae and anteclypeus dark brown (almost black), epicranium entirely dull black; antennae black; rear of head entirely black.

Thorax. Prothorax black with metallic red reflections, anterior lobe brown, propleuron dull ochre. Mesothorax ( Fig. 4 ) with a broad dull metallic purple middorsal stripe followed by a narrow dull ochre antehumeral stripe about 0.20 width of dark middorsal stripe; broad parallel-sided dark dull metallic purple humeral stripe covering entire mesepimeron and anterior 0.80 of mesinfraepisternum; metathorax dull yellow-ochre with a narrow dark brown metapleural stripe extending to dark metinfraepisternum, subalar carina black and metapleural carina edged with brown; venter of thorax yellow-ochre.

Wings slightly flavescent with venation black; pterostigma trapezoidal, dark brown, surmounting 1 cell in all wings; postnodals Fw 17/19, Hw 14/15; postquadrangular cells Fw 5/4, Hw 4/4; RP 2 at Fw 8.5/8, Hw 7/7. Coxae and trochanters orange brown, femora, tibiae, tarsi and armature black.

Abdomen ( Figs. 4 , 10, 12 ) mostly black; S1 black at basal 0.40 dorsally, broadening to basal 0.70 laterally, remainder violet; S2 black with a complete violet oval dorsal spot constricted anteriorly at basal 0.10, narrowing at distal 0.20 and gradually tapering posteriorly before expanding again at distal 0.80 ( Fig. 10 ); laterally with a small pale spot basally and apically; S3 all black with small violet basal ring conjoined with a tapering middorsal stripe ending at basal 0.70 of segment; S3–7 black each with an incomplete violet basal ring; S8 pale dorsally, black laterally, narrowly violet dorsally on basal 0.70 and expanding laterally at apical 0.30; S9 pale dorsolaterally and ventrally black; S10 as in S9; appendages black; torus and torifer pale, extending posterodistally beyond level of S10, in lateral view extending posteriorly half way to length of cercus, occupying entire ventral margin of torifer and not overlapping bilobed epiproct; epiproct black, small, slightly bilobed ( Fig. 22c ); cercus subequal to length of paraproct ( Fig. 22b ), in dorsal view ( Fig. 22c ) swollen basally and abruptly curving mesally at distal 0.50 and terminating as a stump-like process; in lateral and mediodorsal view ( Fig. 22a ) tip of cercus ending in a planar glabrous tooth which in mediodorsal view is differentiated dorsally and ventrally by a slight cleft ( Fig. 22a lower inset); paraproct bilobate, dorsal branch larger, forming an evenly round lobe, ventral branch small, bluntly acuminate and meeting dorsal branch at about a 90° angle ( Fig. 22b ); appendages mostly black, dorsal tip of paraproct pale.

Genital ligula ( Fig. 19 ), with distal segment ending in two filaments, attachment area of filaments lacking an ectal hood, ental surface of distal segment with a hyaline semicircular process, this area smooth, lacking microspinulae, anteriorly forming two parallel lobes sulcate medially ( Fig. 19b ); a sclerotized lateral lobe distal to flexure present terminating as a digit-like process; no microspinulate patch on ental surface of genital ligula proximal to flexure.

Dimensions. Hw 19.0, abdomen 26.5, total length 33.0.

Description of female paratype (same data as holotype). Similar to male but with pale areas olive tan and more extensive ( Fig. 8 ). Head ( Fig. 2 ) as in male but with an incomplete orange cross-stripe below epicranium, this stripe interrupted medially by black from epicranium joining postclypeus, epicranium dorsally with metallic reflections and with a small pale spot anterolateral to lateral ocellus; thorax ( Fig. 8 ) with pale antehumeral stripe olive brown, pale areas of metathorax olive tan; S1 as in male but pale area pale blue, S2 black with pale blue basal ring joining a narrow tapering middorsal stripe ending at medial 0.50; S3–7 black with incomplete pale blue basal ring, S8 black, dull purple on apical half dorsolaterally, S9 as in S8 but pale spot larger, S10 black with a small dull purple lateral spot, cercus black, ovipositor black becoming dark orange dorsodistally (as in Fig. 16 ).

Mesostigmal plates ( Fig. 20 ) forming a low, broadly based lobe occupying medial half of mesostigmal plate and terminating medially at an obtuse angle that is slightly disjunct from lateral margin of middorsal carina; posterior margin of lobe undifferentiated.

Dimensions. Hw 21.0, abdomen 27.0, total length 33.0.

Variation in paratypes. Paratype males similar to holotype but one male ( Fig. 11 ) with dorsal pale spot on S2 separated basally; another male ( Fig. 13 ) with an isolated small black dorsolateral spot on S9; one paratype male juvenile with pale colors lighter than in fully adult males; one female almost teneral and another two juveniles with pale colors dull blue. Pterostigma surmounting 1 cell in all males (N=8) and females (N=10); postnodals: Fw 14–16, Hw 12–14 in males, Fw 14–16, Hw 11–14 in females; postquadrangular cells Fw 3–4 (usually 4), Hw 3 in males, Fw 4, Hw 3 in females; RP2 at Fw 7–9, Hw 6–7 in males, Fw 7–8, Hw 5–6 in females.

Dimensions of paratypes. ♂ (N=8): Hw 20.4 ± 0.7 [19–22], abdomen 26.4 ± 2.4 [21–29], total length 34 ± 1.2 [33–36]. ♀ (N=10): Hw 20.8 ± 0.5 [20–21.5], abdomen 26.5 ± 0.7 [25–27], total length 34.2 ± 1.2 [32–36].

Diagnosis. This species is unique by the combination of absence of postocular spots, torifer elongate and morphology of male cercus. Argia nataliae is most similar to A. rogersi , the latter known thus far only from Costa Rica and Panama. These two species are unique within the genus in always lacking pale postocular spots in both sexes ( Figs. 4–9 ). Specimens of some other largely dark species may occasionally lack postocular spots (e. g. A. calverti Garrison & von Ellenrieder, 2017 ) or have them greatly reduced (e.g. A. translata Hagen in Selys, 1865 ) but this is rare. The genital ligula in the male of A. rogersi is also the same in A. nataliae ( Fig. 19 ). The elongate torus in A. nataliae ( Fig. 22 ) recalls that for A. infumata Selys, 1865 ( Figs. 10 e 4, f4, g 4 in Garrison & von Ellenrieder 2015) but the overall largely orange body coloration and different appendage morphology of the latter easily distinguishes the two. Although A. nataliae is most similar to A. rogersi , both sexes are easily separated by the following structural characters. The male cercus of A. nataliae is subequal in length to paraproct ( Fig. 22b ); in A. rogersi , cercus is smaller, extending to about half the length of paraproct ( Fig. 23b ); in dorsal view, cercus is swollen basally and abruptly curves mesally at distal 0.50 ( Fig. 22c ) terminating as a stump-like process armed distally with a flattened tooth in A. nataliae ( Fig. 22a , lower inset); in A. rogersi cercus is small, semicircular, evenly convex, externally and mediodistally armed with an incurved tooth ( Fig. 23a, c ); in female, mesostigmal plate in A. nataliae possesses a broadly based mesostigmal lobe occupying medial half of the plate ( Fig. 20 ); in A. rogersi mesostigmal lobe is narrower, forming an erect parallel digit-like lobe occupying medial third of mesostigmal plate ( Fig. 21 ). Both sexes of A. nataliae differ from A. rogersi by overall body coloration: A. nataliae with a broad dull metallic purple middorsal and humeral thoracic stripes ( Figs. 4 , 8 ) versus black stripes ( Figs. 5, 6 , 9 ) or, in males of some populations, entire mesothorax black ( Fig. 7 ) in A. rogersi . Overall pale thoracic coloration in males of A. nataliae is a dull ochre versus sky blue or violet in A. rogersi . In females, the pale thoracic color is a dull olive green versus tan in A. rogersi . All of the specimens of A. nataliae examined possessed a complete humeral stripe ( Fig. 4 ). This stripe is forked above in many populations of A. rogersi ( Figs. 5, 6 ). Pale areas of the face are more extensive in A. rogersi ( Fig. 3 ) compared to those of A. nataliae ( Figs. 1, 2 ).

Males of A. rogersi exhibit a more variable body coloration and pattern than do available males of A. nataliae . Calvert (1902) described A. rogersi based on two males from Caché, Costa Rica. He described the mesothorax as entirely black ("...Thoracic dorsum black, with a slight metallic-green reflection; no pale antehumeral stripe; the humeral stripe concolorous and continuous with the thoracic dorsum, and reaching to the first lateral suture, not cleft nor enclosing any pale colour....") indicating a pattern in Fig. 7 but described S8 as "....(very much faded) possibly blue, with an inferior black stripe each side as long as the segment....." as shown in Fig. 14. I have seen only two males that match Calvert's description in thoracic pattern ( Fig. 7 ).

William Haber, who has had much experience with Argia rogersi , responded to my inquiry concerning corporeal variability (24 January 2019):

"The basic situation as I understand it is that the Caribbean slope population of rogersi is dark with the pale markings purple and lacks the antehumeral stripe, while the Pacific slope population, stretching at least from Monteverde to San Isidro, has sky blue markings including a prominent antehumeral stripe and all blue S8. In the Río San Luis where you, Natalia, and I collected, the dark form spills over the Continental Divide (where the Divide has a low spot) from the Caribbean side to the east into the wet, upper end of the Río San Luis valley. Just a little downstream (1.5 km) ( Mauricio Ramirez's farm) we start to pick up the sky blue color form, and that extends further down slope from there. I have not seen the sky blue form on the Caribbean side. As to DNA analysis - yes, I got barcode results for one from Mauricio's stream (sky blue) and two from Reserva Las Brisas near Siquirres. The BOLD analysis said they are 99.56% similar. A 2% difference or more usually indicates distinct species, so I think this is evidence for them being just color forms. I have seen exceptions to this pattern, but in this case, the appendages appear to agree.."

Remarks: The type and only known locality for Argia nataliae, Cristalina , was described by Williamson (1918):

"[Cristalina on the Rio Magdalena] lay in a densely wooded country abounding in beautiful small streams. Conditions were humid, vegetation was rank and small tree ferns were noted. A small stream, the Quebrada Cristalina, flowed directly through Cristalina. The water of this stream was brought from the hills to the village and railroad through an iron pipe. During our first day at Cristalina, February 12, we followed this pipe back to the intake. Between the intake and the town the stream flowed largely through pasture and brushland, but above the intake it flowed in forest. Here it was only two to three feet wide and was frequently lost in the stony, gravelly bed. It had its origin in the hills about a mile above the intake. The richness and peculiarity of its dragonfly fauna may be realized from the fact that our first day's collecting yielded a Miocora, two species of Palaemnema, a Perilestes, three protoneurines, three Heteragrions, a Philogenia, an Allopodagrion, an Acanthagrion, a Megaloprepus, two Mecistogasters, and numbers of Argias, Hetaerinas, and libellulines."

and again ( Williamson 1923):

"[Cristalina is] on the railroad 28 kilometers above Puerto Berrio, the latter town a river port on the Magdaleila 163¾ leagues above Barranquilla, Colombia. At an elevation of about 1,050 feet, Cristalina lies in a rolling forested country and abounds in beautiful small, clear, gravelly streams with many ripples and a very few small waterfalls. These streams vary from a foot or two to six to twelve feet in width and all flow into the Rio Diez-y-seis, a stream of varied character, 15 to 30 feet wide. Collected here February 12-20, 1917."

The type locality is no doubt the small village of Estación Cristalina which is just south of Estación Sabaleticus (ca. 6.41 ° N, 74.58° W, 300m). Williamson penciled the following note on the envelope accompanying the holotype: " ♂ Argia a very peculiar colored sp. as though faded in cyanide fumes; Dark color of thorax a shining dark dull red; pale color a red violet; apex abd, violet blue." The Willliamsons collected this species over a span of nine days, 12 through 20 February. They were known for collecting extensive series. One male and two females collected on the last day (20 February) were very juvenile to teneral and realizing that the species was distinctive, they probably tried to collect all specimens that they saw, which likely indicates that the species was not abundant at the type locality.

Figures

FIGURES 1–7. Color pattern of head, anterior view (1–3); color pattern of head, thorax, S1–4, lateral view (4–7).

FIGURES 8–15. Color pattern of head, thorax, S1–4, lateral view (8, 9); color pattern of S1–2, dorsolateral view (10–11); color pattern of S7–10, lateral (12, 14, 15) and dorsolateral (13) view.

FIGURES 22–23. Male caudal appendages.

FIGURES 16–19. Color pattern of S7–10, lateral view (16–18); genital ligula (19).

FIGURES 20–21. Female mesostigmal plates.