﻿Parartemiopsisshangrilaensis, a new species of fairy shrimp (Branchiopoda, Anostraca) from Yunnan, with a key to the Chirocephalidae of China

﻿Abstract The fairy shrimp genus Parartemiopsis Rogers, 2005 currently contains a single species reported from Russia and Mongolia. In 2013, an unidentified Parartemiopsis population was reported from the eastern margin of the Tibetan Plateau in China’s Yunnan Province, from Patatson National Park in Shangri-La County. Here, we describe the Chinese populations as a new species, Parartemiopsisshangrilaensissp. nov. This new species is distinguished from its congener, P.longicornis (Smirnov, 1930), by the form of the male second antennae and the gonopod. The discovery of P.shangrilaensissp. nov. extends the known distribution of the genus, and more Parartemiopsis species may be found in the future. We present a key to the genera and species of Chirocephalidae in China as an aid to future research.

Parartemiopsis shangrilaensis, a new species of fairy shrimp (Branchiopoda, Anostraca) from Yunnan, with a key to the Chirocephalidae of China Introduction Chirocephalidae is the second largest anostracan family in terms of numbers of species, but it contains the most genera (Belk and Brtek 1995;Rogers et al. 2013). The family contains nine genera, with all but one species (Chirocephalus hardingi Brtek, 1965 from Bali) distributed entirely in the Holarctic. Parartemiopsis Rogers, 2005 was erected (Rogers 2005(Rogers , 2006 to contain Chirocephalus longicornis (Smirnov, 1930). Rogers (2005Rogers ( , 2006 demonstrated that this species warranted a separate genus and was morphologically closer to Artemiopsis Sars, 1897 than to Chirocephalus Prévost, 1803. An unidentified Parartemiopsis population was reported from Yunnan Province (Shu et al. 2013) in a list of crustaceans from Patatson National Park. More material was collected and is described here as a new species. A key to the species in the genus is presented, along with a key to the Chirocephalidae of China. It is our hope that this key will further future studies on the Chirocephalidae of this region.

Materials and methods
Specimens were collected from Patatson National Park in 2012 and 2019 using a dip net. Specimens were preserved on site in 95% alcohol. Specimens were examined in the laboratory under a stereomicroscope (Zeiss Stemi 508 and Wild M8) and a compound microscope (Olympus CX31). For scanning electron microscopy (SEM), specific structures were dissected from individual specimens and put into a 2.5% glutaraldehyde solution for 24 h, washed for 30 min three times with 0.01 M phosphate buffered saline, transferred to a 1% osmic acid solution for 2 h, then washed three times for 30 min each with 0.01 M phosphate buffered saline. Next, the material was treated in an ethanol gradient dehydration series at 30%, 50%, 70%, 80%, 90%, 95%, and 100% for 20 min. The specimens were then put into tertiary butyl alcohol at 40 °C for 2 h and frozen at −20 °C. The material was then freeze-dried in a JFD-310 freeze dryer. Later, the specimens were mounted on stubs and coated with gold in a JFC-1600 sputter coater. SEM images were taken using a TM 1000 Hitachi scanning electron microscope at 10 kV. The pictures were collaged in Photoshop CS.
Terminology follows Rogers (2005Rogers ( , 2006 and Rogers and Soufi (2015). Examined specimens are deposited in the Kunming Natural History Museum, the Kunming Institute of Zoology (KIZ), Chinese Academy of Sciences.

Parartemiopsis Rogers, 2005
Parartemiopsis Rogers 2006, 2013. = Pristicephalus pro partim in Smirnov 1930Brtek 1958. = Chirocephalus pro partim in Brtek 1966, 1967, 1997, 2002Belk and Brtek 1995. Diagnosis. (modified from Rogers 2006). Male genital segments expanded. Entire gonopod basal portion chitinized. Gonopod basal portion bearing a broad lamellar ventral process, originating anterior to gonopod base. Gonopod laterally with tubercle. Gonopod distal eversible portion not cirriform, bearing a few scattered denticles. Militang meadow is in an alpine valley surrounded by mountains covered in coniferous forest. A small river winds through the valley, which receives runoff from the surrounding slopes. The meadow has a mosaic of wetlands and uplands. This species is so far only known from the type locality.
Holotype male. Body red or jacinth in life (Fig. 1C). Head typical for genus. Eye plus peduncle length subequal to first antenna length. Eye large, width >0.2× second antennal proximal antennomere medial width. First antenna long, filiform, extending to second antennae distal antennomere midlength, apex with five or six aesthetascs.
Genital thoracic segments fused, ventrally expanded. Genital segment I (Fig. 3J) smooth, elongate, with paired longitudinal ventromedial ridges, their combined width approximately half segment width. Genital segment I distal margin with bead.
Telson and cercopods as typical for genus. Cercopods margined with plumose setae.
Etymology. The specific epithet "shangrilaensis" refers to the species being from Shangri-La County. The gender is feminine.

Discussion
Parartemiopsis was erected by Rogers (2005) to accommodate the Mongolian P. mongolica; only two male specimens were known at the time. Shortly after publication, Rogers realised that P. mongolica was a junior synonym of the Russian Chirocephalus longicornis (Smirnov, 1930) (Rogers 2006), which was first described in the now unrecognised Pristicephalus Daday, 1910 and then moved to Chirocephalus (Brtek, 1967). However, the female was never properly described, although mentioned briefly by Smirnov (1930).
The males of both Parartemiopsis species share the basic form of the gonopods and the second antennae. Both share the anterior triangular projection on the distal antennomere. Parartemiopsis shangrilaensis sp. nov. is separated from P. longicornis by the form of the male second antenna. The antennal appendage is lobiform in P. longicornis and lamelliform in P. shangrilaensis sp. nov. The proximal antennomere lateral surface bears a large, medial, hemispherical bulge and a subdistal lobe in P. longicornis, which are absent in P. shangrilaensis sp. nov. The distal antennomere is straight in P. longicornis but curves medially in both the basal third and subapically in P. shangrilaensis sp. nov. In P. shangrilaensis sp. nov. the distal antennomere bears a basomedial, spiny, hemispherical protrusion in which is absent in P. longicornis. The form of the gonopod lamella also differs: it is subrectangular, with the length ~2× the length of the gonopod rigid base in P. shangrilaensis sp. nov., but triangular and subequal in length in P. longicornis. Furthermore, the medial spinulae row is elevated on an arcuate carina in P. shangrilaensis sp. nov., whereas this row is flat in P. longicornis. The female P. longicornis is incompletely known and in need of redescription according to modern standards. However, it appears from Smirnov's (1930) description that P. longicornis has paired dorsolateral projections on thoracic segments V-X and small lateral spiniform projections on abdominal segments I-V. In contrast, P. shangrilaensis sp. nov. bears paired dorsal spiniform projections only on thoracic segments X and XI, with the abdomen inerm.
There is no information on the egg morphology of P. longicornis. During fieldwork in 2012, the type locality was dominated by macrophytes, the water temperature was 22.1 °C, with a surface area of approximately 40 m 2 , and the depth was 0.3 m.
Previously, Parartemiopsis was only known from two locations, one in eastern Mongolia (Rogers 2005) and the other near Xingkai Lake or Khanka Lake (Smirnov 1930), near the border between China and Russia; both locations are in northeast Asia. The type locality of P. shangrilaensis sp. nov. is more than 2000 km from those sites. This new locality greatly enlarges the known distribution of the genus. More Parartemiopsis species may be found in future surveys in Asia.

Key to Chirocephalidae of China
Chirocephalus is in great need of revision (Rogers 2013). Recent attempts to erect or resurrect genera from Chirocephalus sensu lato based on small genetic sampling from the genus (Weekers et al. 2002;Naganawa et al. 2020) have only created confusion. The genus, as it currently stands, is probably polyphyletic, but with 60+ species (Rogers 2013), phylogenetic studies on only a handful of species cannot accurately elucidate evolutionary relationships within the group. Until a larger number of species are analysed using standard, modern molecular and morphological techniques, the resurrection or establishment of new genera only creates more confusion. First and foremost, we need a definition of what Chirocephalus is. We need this before we can decide what is not Chirocephalus. Until then, the various proposed generic names remain available.
There are several records of Chirocephalus from China that are questionable. Chirocephalus spinicaudatus var. chyzeri (Daday, 1890) was reported from Tibet by Chiang (1983), but his figures do not agree with the description of that taxon, which is only known from Slovakia and Romania (Belk and Brtek 1995). Similarly, C. graziellae Alonso & Naganawa, 2008 was reported from Tibet by Deng et al. (2021); again, the description provided of the Tibetan material disagrees with the original description and is insufficient to determine what species Deng et al. had. The material from Tibet of both populations needs to be examined and identified according to modern standards. Neither of these forms are included in the key below.

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Male distal antennomere anterior margin with a medial triangular projection; male genital segments enlarged and chitinized with a transverse ridge along ventroposterior margin; gonopod basal portions separated by 3-4× their width; gonopod rigid basal portion bearing a large, ventrome-