Apertochrysa Tjeder, 1966

Breitkreuz, Laura, Duelli, Peter & Oswald, John, 2021, Apertochrysa Tjeder, 1966, a new senior synonym of Pseudomallada Tsukaguchi 1995 (Neuroptera: Chrysopidae: Chrysopinae: Chrysopini), Zootaxa 4966 (2), pp. 215-225 : 216-218

Genus Apertochrysa Tjeder, 1966 , Sensu Novum

Chrysopa (Apertochrysa) Tjeder, 1966: 480 .

Type species (of Apertochrysa ): Chrysopa umbrosa Navás, 1914 , by original designation.

Anisochrysa (Apertochrysa) Tjeder. Hölzel 1973: 341 .

Mallada (Triadochrysa) Adams, 1978: 294 .

Type species (of Triadochrysa): Mallada (Triadochrysa) triangularis Adams, 1978 , by original designation. Syn. nov.

Apertochrysa Tjeder. Tsukaguchi, 1985: 505 .

Triadochrysa Adams. Brooks & Barnard, 1990: 223 [junior synonym of Mallada ].

Navasius * X.-k. Yang & C.-k. Yang, 1990: 327 [an unavailable name in the genus group; spelled identically with, but as an unavailable name not technically a nomenclatural homonym of, Navasius Esben-Petersen, 1936 ]. Type species: none (unavailable genus-group names have no type species). Nominal genus based by X.-k. Yang & C.-k. Yang on the then-unavailable nominal species Mallada eumorphus * X.-k. Yang & C.-k. Yang, 1990. Genus name unavailable under Art. 13.3 as its type species was not validly fixed in its original publication (its cited type species was then an unavailable nominal species and thus ineligible for fixation), and not having been proposed expressly as a new replacement name. Unavailability upheld by ICZN (2010). Syn. nov.

Dichochrysa * C.-k. Yang, 1991: 150 [an unavailable name in the genus group]. Type species: none (unavailable genus-group names have no type species). Genus name unavailable under Art. 13.3 as its type species was not validly fixed in its original publication. Dichochrysa * was proposed expressly as a replacement name for Navasius * X.-k. Yang & C.-k. Yang, with which it is thus objectively synonymous. But, as no type species was originally fixed for Navasius * X.-k. Yang & C.-k. Yang, no type species could be originally fixed for its intended replacement name. Unavailability upheld by ICZN (2010). Aspöck et al., 2001:93 [ Pseudomallada listed in synonymy]. Syn. nov.

Pseudomallada Tsukaguchi, 1995: 67 .

Type species: Chrysopa cognatella Okamoto, 1914 , by original designation. ICZN 2010 [ Dichochrysa * in synonymy]. S yn. nov.

Diagnosis: Apertochrysa is the only chrysopid genus that possesses the following combination of male terminalic traits: (1) sternum VIII+IX simple, rounded posteriorly, (2) tignum usually present, rarely absent (then presumed secondarily lost), and (3) gonapsis always present, its form variable (as noted below). Most Apertochrysa species examined to date can be characterized by one of four generalized gonapsis morphologies ( Fig. 1 ), which correspond closely to four clades of species identified in recent molecular phylogenetic work on the genus ( Duelli et al. 2017, Fig. 1 [as Pseudomallada ]). In addition, in most species of Apertochrysa the basalmost inner gradate crossvein does not arise from the pseudomedia (PsM).

Distribution: Subcosmopolitan (Afrotropical, Australasian, Oceanian, Nearctic, Oriental, and Palearctic).

Discussion

Morphology: Historically, many of the species treated here in Apertochrysa sensu novum were formerly placed within or near the genus Mallada Navás, 1925 (e.g., Brooks & Barnard, 1990). However, recent molecular phylogenetic analyses (Mochuzuki et al., 2017; Garzón-Orduña et al., 2019; Winterton et al., 2019) have established that Apertochrysa and Mallada , while similar, are not closely related, and can be distinguished on the basis of the shape of the gonapsis (see particularly, Duelli et al., 2017), a sclerotized male terminalic element that lies medially in the posterior body wall above the (8 th +)9 th sternite. The gonapsis of Apertochrysa can assume a variety of forms ( Fig. 1 ), but always consists of a pair of lateral wings, which are connected to a single anteriorly-directed rod (apodeme) (see Duelli et al. 2017 for detailed descriptions of four distinct gonapsis morphotypes found in Apertochrysa ). Apart from Apertochrysa , there are only four other genera in the Chrysopinae that possess both a tignum and a gonapsis: Anomalochrysa McLachlan, 1883 ; Mallada Navás, 1925 ; Meleoma Fitch, 1855 ; and Peyerimhoffina Lacroix, 1920 . All of these genera have gonapsis shapes that are distinctly different from Apertochrysa , and none of these genera are closely related to Apertochrysa . In the sister genera Anomalochrysa and Mallada the shape and size of the gonapsis also varies, but its form is roughly W-shaped, X-shaped, or Y-shaped. Meleoma has a small bilobed gonapsis, and in Peyerimhoffina the gonapsis is V-shaped. Apertochrysa is also morphologically similar to Chrysoperla Steinmann ; both possess a tignum (rarely absent in Apertochrysa ), but Chrysoperla lacks a gonapsis (present in Apertochrysa ). However, the homology and evolution of the chrysopid gonapsis is still unclear. Structures currently called gonapses are present in some members of all major clades of Chrysopini , but the structures are not present in all species of any of these clades. Current phylogenetic hypotheses for Chrysopidae are neither sufficiently complete nor robust enough to convincingly determine whether the chrysopid gonapsis evolved independently in multiple chrysopid lineages, or evolved only once, followed by independent losses in multiple chrysopid lineages. Interestingly, sclerotized male terminalic elements developed in the posterior membranous body wall below the gonarcus and above the (8 th +)9 th sternite are relatively rare outside the Chrysopinae , being found only in the Belonopterygini in the form of a pair of ventrolateral structures commonly referred to as parameres. Current phylogenetic hypotheses thus support the idea that the gonapsis is not a ground-plan feature of the Chrysopidae . But rather, that the structure has arisen one or more times as a non-basal evolutionary novelty within the family. This observation casts doubt on the idea that the gonapsis may represent a homolog (of sternal or some other origin) shared with other neuropteran families. More comprehensive studies of the evolution of the gonapsis, parameres and similar structures is needed to better understand this issue.

Tignum state was also formerly a major diagnostic feature separating Pseudomallada (present)from Apertochrysa (absent), but recent molecular phylogenetic work suggests that tignum state is phylogenetically more variable than previously thought. In particular, secondary tignum loss may be more common in predominantly tignum-present lineages than earlier assumed, suggesting caution in using tignum presence/absence as the sole or primary character for justifying genus-group taxa in the Chrysopidae .

Taxonomy: Most of the pre-1990 species placed here in Apertochrysa sensu novum were originally described in the genera Chrysopa , Mallada , or Anisochrysa , and many passed through other generic combinations before being gathered into Navasius * by Yang & Yang (1990) and subsequently being transferred to Dichochrysa * X.- k. Yang, 1991. Between 1990 and 2010, ca. 55 additional new species were described in either Navasius * or Dichochrysa *, and ended up residing in Dichochrysa *. More recently, following the ICZNs (2010) ruling on the petition of Oswald (2008), which confirmed the unavailability of the generic names Navasius * and Dichochrysa *, the numerous existing Dichochrysa * combinations were rapidly replaced by new combinations in the synonymous genus Pseudomallada Tsukaguchi, 1995 , which became the third most speciose genus in the family Chrysopidae , with ca. 170 species distributed nearly worldwide.

This work addresses an important taxonomic issue that has arisen from the recent phylogenetic work of Duelli et al. (2017) and Mochizuki et al. (2017) on Chrysopinae . Mochizuki et al. clearly demonstrate that Apertochrysa umbrosa , the type species of the genus Apertochrysa , nests, phylogenetically, deep within a derived clade of Pseudomallada species , rendering Pseudomallada paraphyletic without (the type species of) Apertochrysa . Furthermore, because Apertochrysa has nomenclatural priority over Pseudomallada , the former name becomes a senior synonym of the latter, requiring the transfer of the numerous former Pseudomallada species into a greatlyexpanded concept of Apertochrysa . Further work on Apertochrysa , especially regarding comparative morphology and species level phylogenies, is needed in order to identify and better define distinct clades within this large genus.

Figures

FIGURE 1. Representative gonapses of the four Apertochrysa species groups noted in Duelli et al. (2017), ventral view: A: prasina group, Apertochrysa ventralis (Curtis, 1834); B: alcestes group, Apertochrysa alcestes (Banks, 1911) (after Duelli et al., 2017); C: flavifrons group, Apertochrysa perfecta (Banks, 1895) (after Adams & Garland, 1982); D: venosa group, Apertochrysa venosella (Esben-Petersen, 1920) (after Tjeder, 1966). All Apertochrysa gonapses possess a median rod. The lateral “wings” vary in shape and position. Gonocristae are present only in the venosa group.