A new species of the genus Neopseustis Meyrick, 1909, Neopseustis chentangensis S.Y. Huang & Chen sp. nov., which was confirmed by both morphological and molecular methods, is described from Xizang, China. This is currently the westernmost species in Asia of the primitive lepidopteran family Neopseustidae. The new species is externally reminiscent of N. moxiensis Chen & Owada, 2009; however, it can be easily distinguished from the latter by comparison of the male genitalia and is further distinguished by the large genetic distance in DNA barcodes (COI). The adult and genitalia of the new and similar species have been illustrated. Utilizing our new data, a new classification of the genus is provided, with its members subdivided into four species groups: the meyricki-group, the moxiensis-group, the bicornuta-group, and the chentangensis-group, which are supported by both molecular and morphological evidence. A checklist of the genus and a key to the species groups are also provided.

Classification, Himalaya, India, Neopseustina, new species, Sichuan, Xizang

The family Neopseustidae is a small and archaic lepidopteran family known only by four genera and 14 species and with a peculiar disjunct distribution. Ten of these species are found in Southeast Asia, and the rest are found in South America (Davis 1975; Davis and Nielsen 1980; Davis and Nielsen 1985; Liao et al. 2021). Kristensen (1999) listed several probable autapomorphies for the family, mainly taken from the head, thorax, and abdomen, including the facial scales being restricted to paired lateral and usually swollen patches, the prominent apodemal plate invaginated from the upper base of the propecoxal bridge, the male sternum VII with medial spinose process, etc. Faucheux et al. (2006) studied the antennal flagellum sensilla of several neopseustid species and stated that one sensillum type, called “multiporous large sensillum basiconicum” in their work, is unknown in other lepidopterans except Neopseustidae; thus, the presence of such a sensillum constitutes an autapomorphy of the family. Recent molecular studies have brought new knowledge concerning the phylogenetic position of the family. Mutanen et al. (2010) and Regier et al. (2013) recovered the clade Acanthopteroctetidae+Neopseustidae, but with weak support. Kristensen et al. (2015) found that with the discovery of Acanthopteroctetidae, the clade Acanthopteroctetidae+Acanthopteroctetidae+Neopseustidae (abbreviated as the AAeN clade in that work) was strongly supported, and Acanthopteroctetidae was found to be sister to Neopseustidae. The close relationship is supported by the sharing of a strong precoxal bridge between the prothoracic pleuron and sternum. Moreover, the AAeN clade was found to be sister to all the Heteroneura (Kristensen et al. 2015). Regier et al. (2015) also reported the grouping of Neopseustidae and Acanthopteroctetidae, and this clade was found to be supported by the presence of the smooth intercalary sclerotization and the alignment of antennal scale sockets in longitudinal rows in the antenna. Regier et al. (2015) also suggested that the former monotypic Neopseustoidea should include also the Acanthopteroctetidae and Acanthopteroctetidae, and that together they form the sister group to Heteroneura. Externally, Neopseustidae adults are small to medium-sized moths with long antennae and semitransparent, thin-scaled wings, and they resemble some families in the order Neuroptera. Little is known about the biology of Neopseustidae. Adults can be active during the day or night, flying above bushes or attracted to light traps (Liao et al. 2021; present study). As for the immature stages, Grehan (1991) suggested that the disjunct distribution of the plant family Lardizabalaceae fitted well with that of the family Neopseustidae, but no feeding had ever been recorded. Regier et al. (2015) reported an astonishing parasitoid immature stage on Limacodidae of Neopseustis meyricki Hering, 1925, but later the larvae of this Taiwanese species have been found to feed on Ampelopsis brevipedunculata var. hancei, family Vitaceae (DearLep 2021), suggesting that the former record was based on an error. For other Neopseustidae there is no information on immatures.

To date, two genera and seven species have been recorded from mainland China, which are distributed in Henan, Sichuan, Guizhou, Hunan, Guangxi, and Guangdong provinces (Davis 1975; Chen et al. 2009; Liao et al. 2021). Xizang Autonomous Prefecture, also known as Tibet, is a biological hotspot region located in southwestern China and is well known for its various biotopes. Due to the diverse vegetation types found at different altitudes, this area is home to many families of Lepidoptera, and new discoveries are frequently reported. Neopseustidae are currently unknown for the Xizang fauna. During a survey conducted in May 2021, the first author unexpectedly captured a strange looking individual of this intriguing family from Chentang Town, Xigaze City, located in southern Xizang. After careful examination, this individual has been proven to be an unknown species, which is described herein. This is currently westernmost distribution record of the genus Neopseustis in Asia, and it is also the first record of the family in Xizang. Furthermore, we provide a new classification for the species in the genus Neopseustis, based both on molecular and morphological evidence.

Although Davis (1975) and Liao et al. (2021) considered that the genus Neopseustis should be subdivided into two groups based on the morphology of male genitalia and molecular phylogenetic analysis, we consider that this genus may actually comprise of at least four groups, after utilizing more data from previously unsampled taxa. The first group, as already recognized by Davis (1975) and Liao et al. (2021), consists of N. rectagnatha Liao, Chen & G.H. Huang, 2021; N. meyricki Hering, 1925; N. archiphenax Meyrick, 1928; and N. sinensis Davis, 1975, and is called the meyricki-group. The second group consists only of N. moxiensis Chen & Owada, 2009, and is called the moxiensis-group. The third group, consisting of N. fanjingshana Yang, 1988 and N. bicornuta Davis, 1975, is called the bicornuta-group and probably also includes the unsampled type species, N. calliglauca Meyrick, 1909, based on the morphology of its anellus-juxta-parameres. The fourth group consists of only N. chentangensis S.Y. Huang & Chen and is called the chentangensis-group. Among these four groups, except for the meyricki-group which is unique in having well-developed parameres and a narrow, short, and forked lateroposterior process on the anellus, the moxiensis, bicornuta, and chentangensis groups all share ill-developed parameres, but they can be distinguished from each other by the combination of features in the male genitalia. The moxiensis-group is characterized by the latero-posterior process of the anellus covered by dense spinules from middle to distal end, in addition to the valvae which have an uncinate process apically and a long and thick process ventrally. The bicornuta-group is characterized by the latero-posterior process of the anellus smooth from middle to distal end and the absence of ventral process in the valvae. The chentangensis-group is characterized by latero-posterior process of anellus long, L-shaped with apex deeply bifurcating and bending anteriorly, and gnathos with a large and thick base.

It is rather intriguing that although N. chentangensis is similar externally only to N. moxiensis in Neopseustis, among the whole genus, they have the greatest genetic divergence. Their male genitalia structures are also considerably different from each other, suggesting that the relationship between them is distant. We believe that their external similarity may probably due to their parallel evolution under similar environments. Unlike their relatively whitish congeners inhabiting the mid- and lower-elevation mountainous areas in India, mainland China, and Taiwan, these two species all inhabit high mountainous areas above 2500 m, and the similar cool climate in high elevation areas in western Sichuan and southern Xizang. This probably may have led to the evolution of their dark wing coloration which can help them absorb heat faster. This assumption is also supported by the studies of Wu et al. (2019), Trullas et al. (2007), and Pereboom and Biesmeijer (2003), who produced similar conclusions.

Figures 13, 14. 

13 collecting site of Neopseustis chentangensis in Chentang Town, Xizang 14 Distribution map of some Neopseustis spp. in Asia.

Figure 15. 

Phylogenetic tree of Neopseustidae based on an analysis of the COI barcoding region, using the maximum likelihood method. The genus Neopseustis is divided into four groups with their corresponding anellus-juxta-parameres illustrated on the left side.

The former westernmost record of the genus Neopseustis is the type species N. calliglauca, which is found in the Khasi Hills in India. The current record of this new species is situated about 520 km northwest of Khasi Hill, and thus is currently the westernmost record of the genus. The discovery of N. chentangensis in Chentang, on the southern slope of the Himalayas in Xizang, suggests that the investigation of the microlepidopteran fauna is still inadequate in remote areas along the Himalaya. The collection site of the new species is very close to the border of China and Nepal, and Neopseustidae are unknown in Nepal. It can be expected that this species or other new species will someday be discovered in Nepal or Bhutan. Moreover, Neopseustidae are also expected in the southeastern part of Xizang, where no species are currently found. It is possible that the absence of this family there is only due to a lack of surveys, as poor transportation conditions in past decades makes this paradise of moths difficult to access.

We express our sincere thanks to Dr Shipher Wu for literature assistance and instruction on citing the Dearlep website. We are also grateful to Dr Weixin Liu and Mr Xinyang Jia for assistance with taking photos of genitalia.