Cooperia, Ransom, 1907

3.1 Occurrence of Cooperia View in CoL in deer in the Czech Republic

Despite the relatively high number of deer examined from various parts of the Czech Republic in 2018–2022 (116 deer belonging to seven ruminant species, not shown), Cooperia nematodes occurred occasionally. They were present in only three out of 25 red deer (prevalence = 12.0%) and four out of 30 sika deer (prevalence = 13.3%) and were found only in two regions of northern Bohemia ( Table 1 View TABLE 1 ).

The first site (50 ◦ 39 ′ 32 ′′ S, 14 ◦ 43 ′ 29 ′′ E) was Mimon (the Ralsko hunting ground). One red deer was positive out of the two examined (prevalence = 50%). The intensityof nematode infection was 141 worms.

The second site (50 ◦ 10 ′ 30 ′′ S, 13 ◦ 2 ′ 48 ′′ E) was the hunting ground in the Doupov Mountains directly adjacent to the territory around the village of Valeč. Two red deer were positive out of the 17 examined (prevalence = 11.8%) and they had four and 11 worms, respectively. Four sika deer were positive out of the 20 examined (prevalence = 20%), and the intensity of infection ranged from three to 24 worms.

3.2 Bayesian phylogenetic trees based on two partial gene sequences

The phylogenetic analysis of Cooperia sp. from Czech deer based on 18 sequences of cox 2 and 20 sequences of the ITS1- 5.8S-ITS2 region resulted in six haplotypes (accession numbers OR879242-7) and three haplotypes (accession numbers OR804235, OR804236, and OR804237), respectively. Our data were compared with published data, mainly by Ramünke et al. (6), who compared C. pectinata , C. punctata , C. spatulata , and C. oncophora and also indicated that C. spatulata is most likely only a morphotype of C. punctata and its name should be considered a synonym (Figures 3, 4).

Our Bayesian phylogenetic analyses indicated that Cooperia sp. from the Czech deer represents a new lineage. The cox 2 phylogenetic tree indicated the clustering of this new lineage in the clade containing C. oncophora , despite the low branch support (Figure 3, left). The ITS1-5.8S-ITS2 phylogenetic tree showed that this new lineage represents a sister lineage to C. punctata / spatulata , C. oncophora . Finally, the C. pectinata branch represents the sister lineage to the common cluster described above (Figure 3, right). Also, the phylogenetic tree based on both loci (ITS1-5.8S-ITS2 region and cox 2) ( Figure 4 View FIGURE 4 ) agreed with the cox 2 phylogenetic tree. Thus, the lineage of Cooperia sp. from Czech deer constitutes a new sister lineage to C. oncophora and this common branch is a sister lineage to C. punctata / spatulata . Cooperia pectinata represents the sister lineage to the above cluster.

In conclusion, the Bayesian phylogenetic analysis of combined mitochondrial and nuclear markers (cox 2 and ITS1-5.8S-ITS2 region) supported the existence of a new independent lineage of Cooperia sp. from Czech deer. This analysis confirmed that specimens parasitizing deer game represent a sister lineage to C. oncophora while the congener C. pectinata is more distantly related. These results indicate a high probability that Cooperia sp. that parasitizes deer game does not belong to the C. pectinata species that parasitizes bovids.

3.3 Morphologicaldescription

The measurements of Cooperia sp. parasitizing deer are expressed in micrometers (µm) unless otherwise noted, based on 30 males and 30 females.

Male: Body 5.98–10.24 mm long, 117–189 wide just anterior to bursa, head diameter 32–40, cephalic vesicle up to 105 wide, esophagus 380–515. Bursa 277–400 wide, spicules 265–348 long, 67 maximum spicule width, with four parts (length × width): “short head” 19 × 32, “barrel neck” 62 × 40, “bulky belly” 174 × 67, and “thin tail” 53 × 18. The butterfly-shaped genital cone is situated in the middle of the bursa, 64–222 behind the posterior end of the spicules. The next important morphological characteristics are the shape and size of the dorsal ray of the male bursa: it is a doublebranched fork with a total length of 180–208 (196 on average), with the main bifurcation at 56% of the total length ( Figures 5 View FIGURE 5 , 6 View FIGURE 6 ). The number of ventrally oriented rays is six on the left and six on the right side, while four are always long and the remaining two are shorter.

Female: Body 7.57–12.74 mm long, its widest part reaching 190–255 behind the vulva, head diameter 33–42, cephalic vesicle 70–77 wide, esophagus 342–622. Vulva opens 2.11–2.70 mm from the posterior end. Anus opens 172–217 from the body end, tail 43– 50 wide at the anus level, narrowing sharplyto the terminal tip. Eggs in the uterus are 55–61 long and 21–30 wide.