Account
What the sources say about this taxon, as written.
description · 
Plazi
( Figs 18–22 ) ? 2009a Ilyocypris cf. mongolica Martens, 1991 —Wrozyna et al. : 8, 12, 14–17, plate 1: 1–8, figs 6–8. ? 2009b Ilyocypris cf. mongolica Martens, 1991 —Wrozyna et al. : 672, 673, plate 3: 7–11. ? 2013 Ilyocypris cf. bradyi Sars, 1890 —Zhang et al .: 40–43, 45, figs 2, 4, 6 (6–10). ? 2015a Ilyocypris bradyi — Song et al .: 587, 589–592, figs 1 (1&2), 3, 4 table 1. ? 2016 Ilyocypris sp.— Akita et al .: 27–30, 35, 37, 38, Figs 3 (16–18), 7, 9, 10, 12, tables 4, 5, 6.
discussion · Plazi
Remarks. The five-segmented L6, inflated proximal end of the ZO, and ‘blade-type’ copulatory process of the Hp indicates that Ilyocypris tibeta n. sp. belongs to the Ilyocypris japonica Okubo, 1990 group of Asian species as defined by Smith et al. (2019) . The new species is particularly similar to Ilyocypris japonica , Ilyocypris mongolica Martens, 1991 and Ilyocypris innermongolica Zhai & Xiao, 2013 in terms of carapace, L7 (with apical hook-like structures on the third segment) and Hp morphologies ( Okubo 1990 ; Martens 1991 ; Zhai & Xiao 2013 ; Smith et al. 2019 ). Differences include the following: The A2 natatory setae of Ilyocypris tibeta n. sp. reach to about the tips of the terminal claws, while these are much longer in the other three species extending significantly beyond the terminal claws by almost 1/2 of their lengths. The setae on the three distal-most segments of the A1 of Ilyocypris tibeta n. sp. are also much shorter than those of I. japonica , I. mongolica and I. innermongolica ( Smith et al. 2019 ; D. Zhai, unpublished data; Zhai & Xiao 2013 ). The copulatory process (st) of the Hp of Ilyocypris tibeta n. sp. is distally more slender than those of both I. mongolica and I. japonica , and most similar to I. innermongolica . The outer lobe (a) is small, narrow and evenly rounded in Ilyocypris tibeta n. sp. , while more angular in I. innermongolica and wider in both I. japonica and I. mongolica . The Hp middle lobe (h) of Ilyocypris tibeta n. sp. is similar to those of I. japonica and I. mongolica , although this lobe is slightly more rounded on the outer distal edge and less inflated in Ilyocypris tibeta n. sp. The Hp middle lobe of I. innermongolica is significantly different to Ilyocypris tibeta n. sp. and the other two species, being distally much less inflated. The ZO of all the male I. mongolica specimens (Zhai & Zhao 2014) have 13–14 rows of spines; while the number is larger in Ilyocypris tibeta n. sp. (16–17), similar to I. japonica (15–17) and I. innermongolica (17–21). The hook-like structures of the L7 are well-developed in Ilyocypris tibeta n. sp. , similar to those of I. mongolica , and more pronounced than those of I. japonica and I. innermongolica . The type locality of Ilyocypris tibeta n. sp. is a small, shallow pond with a soft, yellowish substrate, a few macrophytes and animal footprints around the edges. It was also found in two other places, a pond with a soft mud substrate, and in the riffle zone of a slowly flowing river ( Table 1 ). Altitudes of these sites ranges from 4325 to 4593 m . Several reports of Ilyocypris species from the Tibetan Plateau figure valves that are very similar to Ilyocypris tibeta n. sp. (e.g. Wrozyna et al . 2009a ; 2009b ; Zhang et al . 2013 ; Song et al . 2015a ; Akita et al . 2016 ; see synonymy list above). The carapaces of Ilyocypris species generally show a strong resemblance to each other, but can also show high amounts of intraspecific variation (e.g. tubercle development, and lateral view of the carapace), complicating identification on valves alone (e.g. Mazzini et al. 2014 ; Smith et al. 2019 ). The most reliable characters for identification are found on the appendages and male sexual organs. Thus it is not possible to determine if valves previously figured are definitely conspecific with Ilyocypris tibeta n. sp. , and highlights the importance of soft part examination when possible. The scattered known localities of living (and possible conspecific sub-fossil) material of this species suggests that it could be widespread at least in the southern and western parts of Tibet , and it probably favours shallow, muddy habitats.