Chrysopodes (Neosuarius) nigricubitus, Tauber & Tauber, 2010

Tauber, Catherine & Tauber, Maurice, 2010, Two new endemic species of Chrysopodes (Neosuarius) (Neuroptera, Chrysopidae) from the Galapagos Islands, ZooKeys 42 (42), pp. 47-78 : 60-67

Chrysopodes (Neosuarius) nigricubitus sp. n.

urn:lsid:zoobank.org:act:646120EF-5C0A-4E4E-A5BA-AEF94688B05A

Diagnosis. Chrysopodes (Neosuarius) nigricubitus , the second species of endemic Chrysopodes (Neosuarius) to be recognized from the Galápagos Archipelago, currently is known from two islands: Santa Cruz [Table Mountain (440 m) and Horneman Farm (220 m)] and Pinta (west side of island, 420 m). The adults of this species share many features with C. (N.) nigripilosus and C. (N.) pecki : they have small, robust, brownish bodies, brown head and facial markings, relatively narrow wings with a narrow costal area, and cream-colored wing venation marked with black (Figs 1, 2, 4). However, a suite of distinguishing features (external and internal) in both males and females indicates that these specimens represent a distinct species.

The most prominent distinguishing feature of the species is the suffusion of black or dark brown pigment (coloration) around many of the crossveins on the forewings ( Figs 4b , 5b ). This suffusion is absent from the other two Chrysopodes species on the Galápagos Islands. In C. (N.) nigricubitus , the second cubital crossvein bears a distinct, dark brown to black swelling that is absent from C. (N.) nigripilosus and small on C. (N.) pecki . Also, there are consistent differences between the species in the length: width ratios of the pronotum and abdominal tergite 6; for both structures, the C. (N.) nigricubitus ratios are intermediate between those of C. (N.) nigripilosus and C. (N.) pecki (Tables 2, 5). Among the specimens that we studied, there was no overlap between the species in the values of any of these traits. In addition, the abdominal sternites of female C. (N.) nigricubitus are cream-colored to light tan, without dark brown areas like those on the S5-S7 of C. (N.) nigripilosus and C. (N.) pecki females ( Fig. 6 ).

Although the C. (N.) nigricubitus genitalia resemble those of C. (N.) nigripilosus and C. (N.) peck , there are distinguishing features in the C. (N.) nigricubitus males. First, unlike C. (N.) nigripilosus and C. (N.) pecki , in which the lateral arms of gonarcus are directed downward next to the mediuncus, in C. (N.) nigricubitus the gonarcal arms are spread widely (Fig. 10c vs Figs 9c & 11c). Only the tips of the gonarcal arms bend downward, and the gonarcal structure is relatively flat in lateral view. Second, in C. (N.) nigricubitus . the horizonal apodeme along the ventral margin of T9+ectoproct is relatively straight (lateral view), not arched as in C. (N.) nigripilosus . The tip of the caudal branch of the apodeme is pointed and without a flange; whereas in C. (N.) nigripilosus it is forked, with both tips rounded, and with the upper fork having a flangelike membrane attached (Fig. 10a).

In the female genitalia, we detected small, but consistent differences between C. (N.) nigricubitus and the other two Galápagos species. First, the sclerotized portion of the C. (N.) nigricubitus spermathecal duct tends to be slightly shorter than that of C. (N.) nigripilosus (0.65 vs. 0.40 mm) (Table 5). Second, the tip of the distal knob of subgenitale is slightly more elongate than that on the two other species, and, third, the pouches near the base of the bursal glands are flat and folded as in C. (N.) nigripilosus but not C. (N.) pecki (Compare Fig. 15b with 15a, 15c).

Description. All features are as described for C. (N.) nigripilosus except as follows. Head (Table 2, Fig. 2): Vertex: surface with small, amber setae. Labrum: distal margin with slight mesal cleft. Coloration. Head cream-colored frontally, tan to light brown dorsally, with brown streak lateral to eyes; frons with pair of oblong, brown marks below most of lower margin of torulus; clypeus with lateral margins dark brown; toruli cream-colored to light tan, with brown border surrounding sclerotized margins; dorsal torulus with dark brown, vertical streak. Genae dark brown ventrally, white stripe above, dark brown dorsally. Scapes tan, unmarked; pedicel tan to light brown; flagellum light brown. Maxillary palp: basal two segments cream-colored. Venter: lateral margins of submentum cream-colored to tan.

Thorax (Table 2, Fig. 2b). Pronotum approximately same width as length; with mottled light brown markings. Mesonotum: with setae short, delicate, amber. Pleural areas: cream-colored, without markings. Legs: setae amber.

Wings (Table 4, Figs 4b , 5b ). Costal area: greatest height ̴0.16–18 times height of wing; tallest at costal cell (#4–6). Subcosta: two subcostal crossveins below stigma. Nine to eleven radial crossveins (between R and Rs); ma considerably more thickened than the Rs at rx1; two rows of gradates; inner row with three to four gradates, outer row with five to six, both rows in regular pattern. Cubitus thickened near furcation; icux2 curved, with dark brown, bubble-like expansion mesally.

Figures 9–ĮĮ. Male terminal structures. 9 Chrysopodes (Neosuarius) nigripilosus Į0 C. (N.) nigricubitus ĮĮ C. (N.) pecki a terminal segments of abdomen, lateral view (scale = 0.5 mm, all images in row) b gonarcus, dorsal view (scale = 0.1 mm, all images in row) c gonarcus, lateral view (scale = 0.1 mm, all images in row). s.dt., setose duct. Note: The gonarcal arms of C. (N.) nigripilosus (Fig 9b) are unnaturally splayed here by the coverslip; the tips typically are below the edge of the gonarcal bridge

Hindwing: length approximately three times height. Nine to eleven radial crossveins; three to four inner gradates; five to six outer gradate veins; three b cells; t cell usually present.

Forewing: alar surface surrounding many crossveins with suffusion of brown to dark brown. Stigma very slightly opaque; costal veinlets within stigma brown to black. Base of Rs, rx1 dark brown to black; icux2 dark brown to black, with dark brown, bubble-like swelling mesally. Hindwing: stigma very slightly opaque; veinlets within stigma, dark brown, with dark brown pigment in surrounding area; gradates, icux2 cream-colored to light brown.

Abdomen (male & female) (Table 5, Figs 6 , 10). Sternites cream-colored with cream-colored setae, without brown areas. Tergites 6, 7: length: 2.1–2.2 (T6), 1.2–1.9 (T7) times greater than height (lateral view). Spiracles ̴ 0.04–0.05 mm diameter.

Table 3. Range of variation in wing characteristics among geographic populations of two Chrysopodes (Neosuarius) species from the Galápagos Islands.

Figure Į2. Female terminus, exterior, lateral view. Chrysopodes (Neosuarius) nigripilosus . c.c. callus cerci g.l. gonapophysis lateralis sg subgenitale s.p. setose subrectal plate S7 seventh sternite T8 eighth tergite T8 ext, ventral extension of eighth tergite T9+ect fused ninth tergite and ectoproct.

Male. (Table 5, Fig. 10): Apodeme of T9+ectoproct straight to very slightly arched; ventral branch lightly sclerotized; caudal branch acute unforked tip (Fig. 10a). Callus cerci taller than wide (0.15–0.23 mm tall, 0.13–0.18 mm wide), with 34–37 trichobothria. S8+9 length 1.5–1.8 times proximal height; shape in lateral view: triangular, tapering to relatively acute apex. Gonarcus: gonarcal arms extending outward from distal margins of bridge; span of gonarcus near arch 0.27–0.35 mm, span between gonarcal apodemes distally 0.64–0.68 mm. Gonarcal apodemes long, narrow, ̴ 0.32–0.37 mm long. Mediuncus: sclerotized surface smooth, with some microsetae laterally; membrane immediately below beak (base of gonosaccus) with large patch of microsetae or gonocristae surrounding base of setose glands.

Female [Table 5, Fig. 15b; see C. (N.) nigripilosus , Figs 12, 13, 14]. Tergite 8: height of fully sclerotized portion less than length of sclerite; height of sclerite (including less sclerotized ventral extension) ̴1.4–1.6 times length. Ninth tergite + ectoproct (lateral view): distal margin with dorsal and ventral bulges. Callus cerci taller than broad (0.15–0.19 mm tall, 0.14–0.15 mm wide), with ̴28–32 trichobothria. Gonapophyses laterales ̴0.4 times height of T9+ectoproct; ̴2.9–3.3 times taller than wide. Sternite 7: length ̴1.6–1.7 times height of proximal margin (lateral view). Subgenitale narrow, rounded, with broad, tongue-like process distally; base consisting of transversely folded, uninvaginated membrane; lateral margin with pair of small, flat pouches, near but separate from base of bursal glands; pouches ̴1/3 length of spermatheca. Bursal glands: accessory ducts not observed to be branched distally. Spermatheca: 0.10 mm diameter at mouth (distal end), 0.18 mm diameter in midsection (widest area), 0.5–0.6 mm long; invagination oblong, extending ̴1/2 length of spermatheca (length 0.23–0.25 mm). Spermathecal duct: ̴ 0.4 mm long (not including pale, brushy tip).

Type material. The holotype (a male) is in the California Academy of Sciences Collection, San Francisco , CA. It is from a series of specimens collected in 1964 by David Q. Cavagnaro during an Academy expedition to the Galápagos. The type locality is Ecuador, Galápagos Archipelago , Isla Santa Cruz , Table Mountain , 440 meters. The labels on the holotype read: (1) Galápagos Arch. / Isla SantaCruz / Table Mtn. 440 M. / IV- 16-1964; (2) D. Q. Cavagnaro / Collector; (3) HOLOTYPE / Chrysopodes (Neosuarius) nigricubitus Tauber & Tauber , des. 2010 [red]. Good condition; glued to point. Altogether, there are 27 paratypes, including thirteen (3M, 8F, 2 teneral, sex undetermined) with identical collection data and yellow paratype labels. Five other paratypes (3M, 2F) have the following data: (1) Galápagos Arch. / Isla SantaCruz / HornemanFarm / 220M V-7-1964; (2) D. Q. Cavagnaro / Collector; (3) PARATYPE / Chrysopodes (Neosuarius) nigricubitus Tauber & Tauber , des. 2010 [yellow]. Nine paratypes (4M, 5F) are in the Institut royal des Sciences naturelles de Belgique, Bruxelles ; these specimens are in alcohol, and their printed labels read: (1) Ecuador, Galápagos, Pinta , western side of island, 420 m, 30/II/2000, L. Baert, K. Desender & J.-P. Maelfait, B.00/0100; (2) PARATYPE / Chrysopodes (Neosuarius) nigricubitus Tauber & Tauber , des. 2010.

Etymology. The name, nigricubitus , calls attention to one of the species’ most prominent distinguishing features – the dark brown to black, heavily sclerotized, second intracubital crossvein [nigri- (Latin, prefix), cubitus (Latin, noun, masculine)].

Specimens examined. Type material only.

Intraspecific variation. The variation among the specimens we studied is small. See Tables 1, 3 & 5, for the ranges in head size and wing features. One male in the series from Pinta has particularly weakly pigmented wings and genitalia intermediate between C. (N.) nigripilosus and C. (N.) nigricubitus .

Figures

Figure 4. Forewing. Į Chrysopodes (Neosuarius) nigripilosus 2 C. (N.) nigricubitus 3 C. (N.) pecki. icux2, second intracubital crossvein; i.g., inner gradate veins; ma, median arculus; scx, subcostal crossveins (between subcosta and radius). The scale applies to all images.

Figure 5. Base of forewing. a Chrysopodes (Neosuarius) nigripilosus b C. (N.) nigricubitus c C. (N.) pecki. icux2, second intracubital crossvein; ma, median arculus.

Figure 6. Abdomen, ventral view.a Chrysopodes (Neosuarius) nigripilosus male b Chrysopodes (Neosuarius) nigripilosus female c C. (N.) nigricubitus female d C. (N.) pecki female. The scale applies to all images.