Kymachrysa, Tauber, Catherine A. & Garland, J. Allan, 2014

Tauber, Catherine A. & Garland, J. Allan, 2014, Kymachrysa, a new genus of Nearctic Green Lacewings (Neuroptera, Chrysopidae, Chrysopini), ZooKeys 437, pp. 87-108 : 88-99

Taxon classification Animalia Neuroptera Chrysopidae

Genus Kymachrysa gen. n.

Type-species.

Chrysopa placita Banks, 1908: 259.

Distinguishing adult features.

Kymachrysa adults appear to be typical chrysopine lacewings of medium size and green coloration. Their most distinctive adult features occur in the male and female terminalia; in addition, a few external features are diagnostic of the genus:

External features.

(i) The longitudinal (radial) veins between the first and second rows of gradate veins of the fore and hind wings are sinuous (Fig. 1A, B), whereas in most other chrysopid genera they are relatively straight. (ii) In both males and females, the fused ninth tergite and ectoproct is completely divided by a dorsal invagination, and each side of the terminal abdominal segment is rounded posterolaterally (especially in males) (Fig. 1 C–F). Among other New World genera, a complete dorsal invagination of the T9+ect is reported only for Chrysopiella and Parachrysopiella ( Brooks and Barnard 1990).

Male terminalia.

One of the most striking aspects of the Kymachrysa male terminalia is the S8+9, which is entirely fused and well sclerotized as in most chrysopine genera. However, in lateral view, the Kymachrysa S8+9 has an unusual ventral bend, and the ventral apodeme is heavy and elongate - extending anteriorly well beyond the proximal margin of S8 (Fig. 2A, B). In ventral view, S8+9 is constricted mesally and rounded both anteriorly and posteriorly (Fig. 2C, D). These features are unique among New World chrysopids.

Gonocornua are present on the gonarcal bridge, as in Ceraeochrysa . In Ceraeochrysa , the gonocornua are usually rounded and unarticulated, and they arise laterally from the gonarcal bridge (see Freitas et al. 2009). But, the gonocornua of Kymachrysa are unusual in that they appear at least partially articulated or separated from the gonarcal bridge, and at the base they are juxtaposed and located mesally on the distal margin of the gonarcal bridge (Fig. 2E, F). Furthermore, the dorsum of the mediuncus has a distinct, trough-like shape not found in other genera; the terminus has a weak, lightly sclerotized or membranous beak mesally and expanded membranous sacs laterally.

Female terminalia.

Two notable features distinguish the female genitalia. (i) This chrysopid genus is the only one outside of the tribe Belonopterygini (see Tjeder 1966: 235, 324, 337) in which the female is reported to have a praegenitale. [Note: the recording of a praegenitale for Leucochrysa (data matrix of Brooks and Barnard 1990: Table 1) appears to be an error - the description of the genus, p. 248, states that the structure is absent.] Moreover, the structure appears unique among chrysopids, in that it is asymmetrical (a condition not reported for Belonopterygini ) (Fig. 3C, D). (ii) The spermatheca is shaped like a pillbox with a shallow invagination and a sail-shaped velum that opens via a slit to the bursal duct (Fig. 3 F–H). By comparison, in Ceraeochrysa the spermatheca is cylindrical, with an elongate invagination and a U-shaped or J-shaped bend that opens via a slit directly to the bursa copulatrix (e.g., Adams and Penny 1985, Freitas and Penny 2001, Sosa and Freitas 2010, 2011). And, in Chrysopodes the spermatheca is cylindrical or tubular, with a very deep invagination and an elongate bursal duct (e.g., Adams and Penny 1985, Freitas and Penny 2001, Tauber 2010, Tauber et al. 2012). (iii) Finally, the Kymachrysa spermathecal duct (mature specimens) is hairy for almost its entire length; the terminal bristles are long and fine, and their length decreases proximally; at the base of the duct the bristles are very short and stubby, or granular in appearance (Fig. 3E, F).

Description.

Adult (Figs 4, 5, 8C, D). Delicate, slender, medium sized (forewing length, Kymachrysa placita : 11-13 mm; Kymachrysa intacta 11-15 mm), predominantly green with yellow longitudinal stripe, mesally. Head (Figs 4, 5). Vertex with pair of crescent-shaped, red or brown sublateral marks (sometimes absent or faint), usually with lateral red or brown stripe near margin of eye; frons with or without markings; gena with red or brown longitudinal markings. Distal segments of labial, maxillary palpi with elongate, lateral, black marks. Antenna cream colored, without markings. Thorax (Figs 4 E–H, 5 F–J, 8C, D). Prothorax variable in length and shape (probably developmental variation), usually long, tapered distally; dorsum without lateral stripes, but usually with irregular, red or brownish, sublateral markings (especially western, southern specimens); mesothorax, metathorax with or without markings. Legs mostly light green, without markings, with numerous dark brown to black setae; tarsal claws with deep U-shaped to V-shaped cleft.

Wings (Fig. 1A, B) with costal area slightly enlarged basally; radius straight; im3 cell triangular; forewing, hindwing with two, regular, slightly converging rows of gradate veins; longitudinal veins between inner and outer gradates sinuate; three icu cells, distal one open.

Abdomen (Figs 1 C–F, 2A, B, 3A, B, 6A, 7A, 8A, B) with spiracles simple; callus cerci round, located dorsally on T9+ect, with trichobothria stemming from closely spaced sockets; ninth tergite (T9) and ectoproct fused, forming T9+ect; T9+ect completely divided dorsally.

Male abdomen (Figs 2, 6-8) slender, with sternites tall (~0.7 × length), with or without microtholi; spiracles simple; terminal segments (A8-A9) compact; ectoproct with heavy apodeme along entire dorsal margin, terminus reaching proximal edge of eighth sternite (S8); eighth and ninth sternites fused; S8+9 shallow, with dorsal surface undulating, anterior section of S8+9 with heavy ventral apodeme extending proximally well beyond margin of segment, into S7; ventral surface indented mesally (hour-glass shaped). Gonapsis, hypandrium internum attached to membrane at tip of S9; gonapsis elongate, with basal margin rounded, toothed, distal margin expanded, curved; gonocristae absent. Gonarcus arcuate, with stout bridge, rounded, expanded lateral apodemes; gonocornua triangular, articulated on laterodistal margin of gonarcal bridge; base of gonocornua clear, tip dark, heavy, tapering to angulate terminus; entoprocessus absent. Mediuncus weak, comprising very lightly sclerotized, curved, mesal band distal to gonocornua, with trough-shaped dorsal surface, small, rounded, membranous terminus. Gonosaccus large, expanded dorsally as pair of large, eversible, distal sacs, expanded ventrally with a second pair of large, eversible sacs; gonosetae absent.

Female abdomen (Fig. 3) robust, not slender; terminalia compact. Praegenitale present, extending as truncated lobe from distal margin of S7, with distal, asymmetrical lobe, comb-shaped, with single long seta; lobe extending distally beyond S7 or curving internally. Colleterial gland, reservoir membranous, very delicate, extending proximally well into A7; transverse sclerite relatively large, broad, comb-shaped, with elongate teeth. Spermathecal complex simple; spermatheca small, pillbox shaped with small to moderate, U-shaped invagination, sail-like velum, opening to bursa copulatrix via elongate slit and small, membranous bursal duct; spermathecal duct elongate (>3 × width of spermatheca), curvy, covered with fine hairs throughout (mature specimens), most dense, long distally, becoming short, stubby basally; immature specimens with basal ~10-20% of spermathecal duct smooth. Bursa copulatrix small, delicate, membranous, sac-like; bursal glands either absent or very small. Subgenitale large, robust, triangular in ventral view, with pair of distal lobes, extending outward or concealed beneath ectoprocts.

Etymology.

The prefix “Kyma-” comes from the Greek word kýma (κύμα), meaning wave, and refers to the wavy, or sinuate, longitudinal veins between the gradate veins of the forewings that distinguish the two species currently assigned to the genus. The suffix follows the traditional series of chrysopid names ending in “-chrysa” - Greek, feminine, “χρυσα” meaning golden.

Geographic distribution.

The genus, which currently includes only two species, appears to be restricted to North America (Canada, United States and Mexico, as far south as Mexico City) ( Adams 1982, Penny et al. 1997, Tauber 2003, Valencia Luna et al. 2006, Garland and Kevan 2007, Freitas et al. 2009, Tauber and Flint 2010, all as Ceraeochrysa or Chrysopodes ).

Characteristics of Kymachrysa larvae.

The larvae of only one of the Kymachrysa species ( Kymachrysa intacta ) were described ( Tauber et al. 1998, as Ceraeochrysa placita ). Later they were shown to share a large number of distinctive characteristics with the larvae of several species of Chrysopodes , and as a result the species was transferred to Chrysopodes ( Tauber 2003, as Chrysopodes placita ).

Recently, larvae from additional species of Chrysopodes were described in sufficient detail for more robust comparisons than were possible earlier. Now, detailed larval descriptions are available for six of the 47 currently recognized species of Chrysopodes [ Tauber 2003: Chrysopodes (Neosuarius) collaris (Schneider); Silva et al. 2013: Chrysopodes (Chrysopodes) divisus (Walker), Chrysopodes (Chrysopodes) fumosus Tauber & Albuquerque, Chrysopodes (Chrysopodes) geayi ( Navás), Chrysopodes (Chrysopodes) linaefrons Adams & Penny; Chrysopodes (Chrysopodes) spinellus Adams & Penny]. Comparisons with these species confirm that Kymachrysa intacta larvae differ only slightly from those of Chrysopodes . And, given the large percentage of species in both Kymachrysa and Chrysopodes with undescribed larvae, it is not clear at this time, which, if any, of these differences will be informative at the generic level.

Nevertheless, the following features appear most noteworthy:

(a) Setae: Previously, certain setae on the Kymachrysa intacta Semaphorant B were reported to be “serrated” or “thorny”, similar to those on Chrysopodes ; these setae include the LS of the thorax and A4-A8, the large LDS on A6 and A7, and some dorsal thoracic setae ( “serrated”: Tauber et al. 2000, as Ceraeochrysa placita ; “thorny”: Tauber 2003, as Chrysopodes placita ). Subsequent comparison of these setae with those of the six described Chrysopodes species (under higher magnification) indicates that the setal surface of Kymachrysa intacta (Semaphorant B) falls outside the range of variation exhibited by Chrysopodes (Chrysopodes) and Chrysopodes (Neosuarius) . Rather than serrated or thorny, the Kymachrysa intacta setae have a more sabulose (sandy) or granular surface (Fig. 9 C–F). [Note: the same setae on Semaphorant A are thorny on both Chrysopodes and Kymachrysa intacta .]

(b) Metathoracic fold: One of the primary reasons for transferring Kymachrysa intacta to Chrysopodes ( Tauber 2003, as Chrysopodes placita ) was the shared characteristic of an unusual posterior fold on the larval metathorax. In both taxa, the fold rises well above the anterior part of the metathorax, and it bears a transverse row (R1) of robust setae that stem from enlarged chalazae and that are usually slightly longer than the submedian setae (SMS) on abdominal segments A1 through A6. However, subsequent comparisons indicated that aspects of this feature present some small, but significant differences between Kymachrysa intacta and Chrysopodes .

First, as discussed above, the surface of the R1 setae on Kymachrysa intacta Semaphorant B is distinctive. It is sabulose (sandy), not thorny as in Chrysopodes .

Second, although the body dimensions of the L3 larvae of Chrysopodes (Chrysopodes) and Kymachrysa intacta that we studied are similar, the length, robustness, and stiffness of the setae differ between the two taxa (Table 1, Fig. 9). For example, in Chrysopodes (Chrysopodes) , the R1 setae range in length between 0.28-0.42 mm, and they are thick and erect throughout their entire lengths. In comparison, the Kymachrysa intacta R1 setae range between 0.48-0.62 mm; they are slender throughout, and only the basal section stands erect - the distal section tends to curve. [Note: In the large bodied Chrysopodes (Neosuarius) collaris (Schneider), both the R1 setae and SMS are slightly longer and more slender and flexible than those of Chrysopodes (Chrysopodes) species (Table 1).]

Third, the larvae of Chrysopodes spp. (all instars, including the first) have dark brown markings on the frontal surface of the chalazae in metathoracic R1; these markings are elliptical to ovate and at least as broad as the setal base. In Kymachrysa intacta (second and third instars) they are light brown in color, elongate, and narrower than the setal base (Fig. 9A, B); they are either absent or very light in first instars.

Biological features of Kymachrysa .

Adult specimens of Kymachrysa placita are not common; those that we have seen were collected during July and August. No larval specimens are reported. Kymachrysa intacta appears to be more abundant; we have seen adult specimens collected from June through mid-October (mostly August), and we have collected larvae during March and April (overwintering second instars) and in September and October (prehibernal first instars).

Biological features have been investigated only for Kymachrysa intacta ( Tauber et al. 1998). In populations from both eastern and western USA (NY and CA), eggs are laid and larvae occur on the trunks of medium-sized to large-sized deciduous and evergreen trees. The larvae are debris-carriers; typically they carry pieces of bark or other woody or plant material that blends with their typical substrate (Fig. 10).

Developmental stages are relatively prolonged, and they are strongly influenced by photoperiod ( Tauber et al. 1998). The life cycle appears to be univoltine. Larvae overwinter as diapausing second instars. Short daylengths decelerate development during the first instar, and they induce and maintain hibernal diapause in second instars. Daylength also may be important during the postdiapause developmental period. Under field conditions (Tompkins and Schyler Counties, NY), adults emerge in June, and eggs occur from July through late September or early October. Such a life cycle is unusual, but not unknown, for other chrysopids. For example, free-living second and third instars of Pseudomallada species also overwinter in a photoperiodically induced diapause ( Principi and Sgobba 1987, 1993, Canard at al. 1990).

Kymachrysa 's generic relationships.

With the addition of Kymachrysa , a total of 17 genera of Chrysopini are now known from the New World. Table 2 lists the eleven that are reported from North America, including Mexico, and it provides references to their distributions.

Above, we showed that Kymachrysa adults (males and females) express a number of characteristics that provide strong morphological support for a distinct genus. However, its relationship with other chrysopine genera remains perplexing. In general, the male genital structures resemble those of Ceraeochrysa , whereas the female genitalia (apart from the presence of a praegenitale in Kymachrysa ) appear similar to those of several other genera (e.g., Ungla , Pseudomallada ). Finally, its larval morphology is very close to that of Chrysopodes , and its biological traits (larval habitat, overwintering stage, photoperiodically controlled diapause) resemble those of Pseudomallada . Resolution of the dilemma posed by the above mixture of similarities awaits a broadly based phylogenetic analysis of chysopid genera.