Sisyroneurorthus, Nakamine & Yamamoto & Takahashi & Liu, 2023

Nakamine, Hiroshi, Yamamoto, Shuhei, Takahashi, Yui & Liu, Xingyue, 2023, A remarkable new genus of Nevrorthidae (Neuroptera, Osmyloidea) from mid-Cretaceous Kachin amber of northern Myanmar, Deutsche Entomologische Zeitschrift 70 (1), pp. 113-120 : 113

Genus Sisyroneurorthus gen. nov.

Figs 1 , 2 , 3 , 4

Type species.

Sisyroneurorthus aspoeckorum sp. nov., here designated.

Diagnosis.

Sisyroneurorthus gen. nov. can be distinguished from the other nevrorthid genera by the combination of the following characters. Forewing: costal crossveins simple; ScP fused with RA at distal fourth; CuA and CuP diverging well distad 1m-cu; cua-cup crossvein absent; a long oblique crossvein present between CuP and A1. Hind-wing: CuA with pectinate branching on distal half, all branches simple.

Species included.

Sisyroneurorthus aspoeckorum sp. nov.

Etymology.

The new generic name is a combination of " Sisyra " (Greek, the name of the type genus of Sisyridae ) and " Neurorthus " (Greek, the common suffix of the generic name of Nevrorthidae ) with reference to the mosaic characters with Sisyridae and Nevrorthidae in the new genus.

Remarks.

This new genus is placed in Nevrorthidae by the presence of three radial crossveins and the long distal half of CuA with 10 branches and nearly parallel with the posterior wing margin in the hind-wing. Interestingly, the new genus shares the distal fusion of the forewing ScP and RA due to the terminal curve of ScP with many species of Sisyridae . Wichard et al. (2009) use the fusion/separation of ScP and RA to distinguish Sisyridae and Nevrorthidae in their key to the aquatic Neuroptera in the Eocene Baltic amber. However, the fusion of ScP and RA in some sisyrids, such as Sisyrina Banks, 1939, Prosisyrina Perkovsky & Makarkin, 2015 and Paleosisyra electrobaltica Wichard, Gröhn & Seredszus, 2009 is atypical because the apical part of ScP is abruptly curved towards RA and the short terminal section connecting to RA can be also interpreted as a crossvein (e.g. 2scp-r in Makarkin and Perkovsky (2016) or 2scp-ra in Yang and Liu (2021)). This feature is just the state present in Sisyroneurorthus gen. nov. and should not be used to place the new genus in Sisyridae . Moreover, all known sisyrids have only two radial crossveins, but lack 1ra-rp in the hind-wing. They also have fewer (usually five or six) branches of hind-wing CuA.

The new genus is most similar to the contemporary genus Cretarophalis Wichard, 2017 by having simple forewing costal crossveins and simple hind-wing CuA branches. However, it differs from the latter genus by the configuration of ScP, which is terminally curved towards RA (in Cretarophalis , ScP runs straight terminally), the position of the crossvein between Cu and A1 (2cu-a1), which is distad separation of CuA and CuP (in Cretarophalis 2cu-a1 proximad separation of CuA and CuP).

Figures

Figure 1. Habitus of Sisyroneurorthus aspoeckorum gen. et sp. nov., holotype female (CAU-BA-NH- 22001) in mid-Cretaceous Kachin amber. A. Dorsal view; B. Left lateral view. Scale bars: 1.0 mm.

Figure 2. Wing venation of Sisyroneurorthus aspoeckorum gen. et sp. nov., holotype female (CAU-BA-NH- 22001) in mid-Cretaceous Kachin amber. A. Right forewing; B. Right hind-wing. Abbreviations. A (a) - anal vein; A 1 - A 3 - first to third anal vein; Cu (cu) - cubitus; CuA - cubitus anterior; CuP - cubitus posterior; M (m) - media: MA - media anterior; MP - media posterior; R (r) - radius; RA - radius anterior; RP - radius posterior; Sc (sc) - subcosta; ScP - subcosta posterior. Scale bar: 0.5 mm.

Figure 3. Details of Sisyroneurorthus aspoeckorum gen. et sp. nov., holotype female (CAU-BA-NH- 22001) in mid-Cretaceous Kachin amber. A. Left anterolateral view of head and antenna; B. Left anterolateral view of mouthparts; C. Right anterolateral view of mouthparts; D. Distinct trichosors present on apical wing margin in right forewing; E. Obscured trichoshors on posterior margin in right forewing. Abbreviations. lp - labial palpus; mp - maxillary palpus. Scale bars: 0.2 mm (A-C); 0.1 mm (D, E).

Figure 4. Terminalia of Sisyroneurorthus aspoeckorum gen. et sp. nov., holotype female (CAU-BA-NH- 22001) in mid-Cretaceous Kachin amber. A. Left lateral view of terminalia; B. Left lateral view of terminalia with white line indicating each segment, gonapophyses and gonocoxite; C. Right ventrolateral view of terminalia; D. Right ventrolateral view of terminalia with white line indicating each segment and gonapophyses. Abbreviations. e - ectoproct; gp - gonapophyses; gx - gonocoxite; S - sternum; T - tergum. Scale bars: 0.2 mm.