Table 1.
Summary of cryptic diversity reported in the literature for nematodes, trematodes and cestodes of human and veterinary importance
| Species | Host | Origin | Studied stage | Molecular markers employeda | Proposed status | Reference |
|---|---|---|---|---|---|---|
| Phylum Nematoda | ||||||
| Ascaris lumbricoides, Ascaris suum | Humans | Kenia | Adults | Mitogenome (4 × ratio < 4), cox1 (1–4 nucleotide differences), nad4, nuclear genome (1% polymorphism in major nuclear alleles) | CGIs | Easton et al. (2020) |
| Toxocara cati, Toxocara malaysiensisb | Cats | Malaysia | Adults | Mitogenome | Cryptic species | Jex et al. (2008) |
| Toxascaris leonina species complex (3 undescribed species) | Dogs, wolves, wild felids, red foxes | Poland | Adults | ITS1, cox1 (1.7–6.58% K2P), nad1 | Cryptic species complex | Fogt-Wyrwas et al. (2019) |
| Strongyloides spp. | Philippine slow loris/humans and dogs | Malaysian Borneo/Australia, Cambodia, Japan, and Myanmar | Third-stage larvae | cox1/18S and cox1 | Cryptic species sensu lato | Frias et al. (2018)/Beknazarova et al. (2019); Jaleta et al. (2017); Nagayasu et al. (2017) |
| Trichinella chanchalensis | Wolverine | Canada | Larval stage not specified | cytb, mitogenome, 15 SCNs | Cryptic species sensu stricto | Sharma et al. (2020) |
| Dirofilaria sp. “Thailand II”/Dirofilaria sp. (D. immitis-like) (2 undescribed species) | Carnivores/humans | Thailand | Adults | ITS1 (17%)/12S (5%), cox1 (6%) | Cryptic species sensu lato | Yilmaz et al. (2016) |
| Onchocerca sp. (1 undescribed species) | Cervids | North America | Microfilariae and adult females | 12S, 16S, cox1 | Cryptic species sensu lato | McFrederick et al. (2013); Verocai et al. (2018) |
| Oesophagostomum sp. (undescribed species) | Human and non-human primates | Uganda | Eggs | ITS2: 2.9% Clade I vs O. bifurcum; 0.6% Clade II vs O stephanostomum; Clade III 7.0–7.6% vs O. bifurcum and 6.4–7.0% vs O. stephanostomum | Cryptic species sensu stricto | Ghai et al. (2014) |
| Teladorsagia boreoarticusb | Sheep and goats | Holarctic | Adults | nad4 (13%) | Cryptic species | Hoberg et al. (1999) |
| Class Trematoda | ||||||
| Opisthorchis viverrini | Cyprinid fish (2nd intermediate hosts) and rodents | Thailand, Laos PDR | Adults | 38 enzyme loci (MEE) (60%) | Cryptic species sensu lato | Saijuntha et al. (2007) |
| Echinostoma “revolutum” species complex (7 described species and 10 cryptic species-level lineages) | Gastropods (1st intermediate hosts), mammals and birds | Europe, North America, South America, Africa, Australia, New Zealand | Cercariae and adults | nad1 (intraspecific divergence: 0–3.6%; interspecific divergence: 4.2–21.5%) | Cryptic species complex | Georgieva et al. (2014) |
| Class Cestoda | ||||||
| Echinococcus granulosus (s.l.) species complex (E. granulosus (s.s.), Echinococcus equinus, Echinococcus ortleppi, Echinococcus canadensis, Echinococcus felidis) | Sheep, dogs, dogs, reindeer/moose, and lion, respectively | Germany, UK, South Africa, Canada and South Africa, respectively | Eggs | E. felidis vs E. granulosus (s.s.), E. equinus, E. ortleppi and E. canadensis G6, G7 and G8, respectively: cox1 (8.4%, 8.1%, 10.6%, 10.6%. 10.5%, 11.1%); nad1 (17.1%, 16.7%, 18.4%, 17.9%, 17.9%, 19.3%); cytb (11.6%, 12.4%, 14.8%, 14.8%, 15.0%, 15.0%); mitochondrial rrn (6.6%, 7.6%, 8.9%, 9.2%, 9.2%, 8.6%); elf-α (1.4%, NA, 0.9%, 1.0%, 1.0%, 0.9%) | Species complex | Hüttner et al. (2008); Romig et al. (2015) |
| Moniezia benedeni, Moniezia expansa | Sheep and cattle | Australia | Adults | 15 enzyme loci (MEE) (92% within M. benedeni, 33% within M. expansa) | Cryptic lineages within groups | Chilton et al. (2007) |
Abbreviation: NA, not available.
a
Genetic divergence in parentheses.
b
Despite described as cryptic in the literature, the species possesses a valid morphological diagnosis.