Santocellus (Neuroptera, Chrysopidae, Leucochrysini): taxonomic changes, new description, and a key to the species

Abstract Santocellus is a small Neotropical genus of leucochrysine lacewings that only recently was separated from Leucochrysa. Here, the features of the Leucochrysa risi Esben-Petersen holotype (a female) are described and shown to support the species’ transfer to Santocellus and the continued retention of the genus Santocellus as separate from Leucochrysa. The valid name for the species becomes Santocellus risi (Esben-Petersen, 1933), comb. n., and Santocellus bullata (Tauber, 2007) is recognized as a syn. n. of Santocellus risi. Currently, this species is reported only from Peru. An illustrated key is provided for distinguishing the known species in the genus Santocellus.


Introduction
The Neotropical genus Santocellus (Neuroptera: Chrysopidae, Leucochrysini) was recently differentiatied from other leucochrysine genera on the basis of a subtle, but consistent, suite of adult and larval traits (Tauber et al. 2008). Currently, the genus contains three species, all from South America: Santocellus atlanticis Tauber & Albu-querque, Santocellus bullata Tauber, and Santocellus riodoce Tauber. One of the species, S. bullata previously was known only from a single male collected in Peru -the holotype at the National Museum of Natural History, Washington DC (USNM) (Tauber 2007). During a recent visit to the Museum of Comparative Zoology (MCZ), a female specimen of this species was discovered; it also was from Peru. However, it had been identified by P. A. Adams as Leucochrysa risi Esben-Petersen. Subsequent examination of the L. risi type [= Santocellus risi (Esben-Petersen)] in the Zoological Museum of Copenhagen University (ZMCU) confirmed Adams' identification and the synonymy of S. bullata and L. risi.
Herein, the features of the previously unknown female are described and illustrated; the results are used to examine the consistency of the female features among Santocellus species. In addition, a key with illustrations for identifying Santocellus species is provided. Methods for staining the abdomen and making measurements were those used previously (see Tauber 2007 (Tauber 2007, as L. bullata).
Female genitalia. Callus cerci round to slightly oval, 0.10-0.15 mm in diameter, with 19-21 relatively thin trichobothria (longest ~0.13 mm long); cupuliform bases of variable diameter. Tergite 9 + ectoproct rounded, fused dorsally, blunt posteriorly, elongate, ventral section on each side enlarged into pair of bulbous lobes extending well below gonapophyses laterales; enlargement covered with dense, stout, upwardcurving setae. Gonapophysis lateralis not large, occupying approximately one-half of posterior margin of abdomen; surface covered with robust, stout setae, especially on ventral half; interior membranous area not greatly expanded. Colleterial gland transparent, delicate, ovoid, small, mostly within gonapophyses laterales and T9+ect, not extending anteriorly much beyond bursa, but with numerous elongate accessory glands attached distally, with transparent, membranous tubule connecting to small reservoir; transverse sclerification short, narrow, receiving short duct from reservoir. Entire geni- tal structure small, not much larger than subgenitale. Bursa copulatrix membranous, broad basally (near subgenitale), tapering and extending slightly into region above S7, folded dorsally, with slight longitudinal depression dorsally, connected ventrally to spermatheca via elongate dorsal slit on spermathecal velum and bursal duct at proximal tip of velum. Bursal duct very short, slender. Bursal glands not seen. Spermatheca doughnut shaped, tucked within distal end of bursa, with small, sail-like velum dorsally, small, V-shaped invagination ventrally. Spermathecal duct attached dorsally to distal end of spermatheca, short, sclerotized, extending into and out of subgenitale, with ~three curves, closely attached to membranes of bursa and subgenitale; terminus with long, dense setae. Subgenitale broad basally, rounded distally, nestled between ventral lobes of ectoproct, narrow in lateral view, with shallow ventral fold at attach- ment to S7, slightly deeper fold above, terminal process flat, long, extending almost full length of subgenitale, with pair of lobes at base, shallow crumena at rounded tip; membrane above subgenitale with crescent-shaped, lightly sclerotized lamellae. Known distribution. Currently, this species is known only from three regions of Peru: Junin (~650 m) (new record), Pasco (~800 m) (Esben-Petersen 1933), and Madre de Dios (250 m) (Tauber 2007).
Comparison with other Santocellus species. The genus Santocellus was described on the basis of a distinctive suite of larval and adult (male and female) character states. However, S. risi (as bullata) was included in the genus only on the basis of its male characteristics (Tauber et al. 2008); both the female and the larvae were unknown when the genus was described. We now know that, in addition to the striking pustulate wings and unusual body markings that typify the species, S. risi  females have abdominal characteristics that are distinctive among the Leucochrysini (setose, bulbous lobes on the ventral margins of the ectoproct and unique, stout, curved setae). However, they also share a large set of female features with their congeners, S. atlanticis and S. riodoce: (1) a round, pillbox-shaped spermatheca with a shallow invagination; (2) a relatively short, lightly sclerotized spermathecal duct; (3) spermatheca with a sail-like velum that opens via a slit to a short bursal duct; (4) spermathecal/bursal complex relatively small, spermatheca nestled below the bursa copulatrix; (5) gonapophyses laterales relatively round and short; (6) colleterial gland bulbous, delicate, transparent, and with several elongate tubules attached to the distal end; (7) subgenitale with two, small to medium-sized, basal folds (at the attachment to the seventh sternite), with a ventral process that is elongate and flat, has a rounded distal margin, rounded lobes basally, and a shallow crumena. The expression of this set of features by the female of S. risi provides new support for keeping the genus Santocellus separate from Leucochrysa, and it offers strong evidence for retaining the species within the genus.

Key to Santocellus Species
The key below is intended for identification without dissecting the specimens. For species-specific differences in male and female terminalia, see Tauber 2007, Tauber et al. 2008, Figs 2 and 3 above). 1 Membrane surrounding numerous crossveins of forewing with pustulate swellings (Figs 4C, 4D); meso-and metanotum each with large, dark brown to black, mesal spot (Fig. 5E)  Forewing with cells between Radial sector (Rs) and inner gradates 5-6 entirely filled with brown, Rs and all crossveins between Rs and Psm without dark clouding (Fig. 4A); mesoscutellum light green (Fig. 5A)  Forewing with cells between Radial sector (Rs) and inner gradates 5-6 only partially filled with brown, Rs and first two crossveins between Rs and Psm with dark clouding (Fig. 4B); mesoscutellum largely brown, posterior with small light green spot (Fig. 5C)