Paracryptotropa peruviana Tkach, Chermak & Patitucci, 2023

Tkach, Vasyl V., Chermak, Taylor P., Patitucci, Kaylyn K., Greiman, Stephen E., Binh, Tran Thi & Olson, Peter D., 2023, Jumping continents and major host lineages: phylogeny and diversity of the enigmatic Cryptotropidae (Platyhelminthes: Digenea), Zoological Journal of the Linnean Society 199 (2), pp. 533-552 : 547

Paracryptotropa peruviana Tkach, Chermak & Patitucci gen. nov., sp. nov. ( Figs 5D , 8 )

Type host: Thalurania furcata Gmelin ( Aves: Trochilidae ).

Site in host: Stomach.

Type locality: San Martín, Peru (8°10 ʹ 41.64 ″ S, 76°13 ʹ 25.32 ″ W) .

Type material: The type series consists of one mature specimen deposited in the HWML. Holotype: HWML 216834 , labelled ex. Thalurania furcata , stomach, San Martín, Tocache Province , Cordillera Azul National Park, Río Pescadero, Peru, 12 November 2013, coll. K. Patitucci.

GenBank sequences: Oº534012 (ribosomal), Oº469317 (cox1).

ZooBank registration: urn:lsid:zoobank.org:act:1FDEC7B3-1A99-4B16-AF75-5622C11E799E .

Etymology: The species is named asser the country where it was collected.

Description (based on one adult specimen; measurements are also in Table 5 ): Body 495 long, broad, flaưened, with rounded anterior and posterior ends and slight constriction at mid-length; body width at level of ventral sucker 302. Body length-to-width ratio 1.6. Forebody 196. Tegument armed with minute spines densely covering entire body. Oral sucker subterminal, rounded, 59 × 74. Ventral sucker round, 66 × 65. Oral sucker width-to-ventral sucker width ratio 1.1. Prepharynx very short, 10; pharynx rounded, 44 × 42. Oesophagus short, 30. Caecal bifurcation immediately anterior to ventral sucker; caeca short, terminating approximately at level of middle of ovary.

Two testes, very large, distinctly lobed, opposite, longitudinally elongated, immediately post-ovarian; anterior margin of testes reaching anteriorly level of mid-section of ventral sucker. Right testis 169 × 125, less testis 201 × 125. Copulatory pouch 125 × 50, median, directly dorsal to ventral sucker; proximal end of copulatory pouch extends posteriorly beyond ventral sucker; anterior end comma-shaped, curved. Genital pore submedian, sinistral, immediately extracaecal, at level of caecal bifurcation.

Ovary 83 × 67, subspherical, immediately posterodextral to ventral sucker, pretesticular.Seminal receptacle not well observed. Mehlis’ gland and Laurer’s canal not observed. Vitellarium extensive, in the form of numerous irregularly shaped follicles forming fields of follicles from the level of the pharynx to posterior end of body. There are almost no follicles in the testicular area, although there is a narrow field of follicles immediately posterior to the testes. Some vitelline follicles are positioned in the middle third of the body between the two main fields. Uterus ventral to gonads, reaching posteriorly between testes to level of mid-length of testes. Metraterm weakly defined, 50 in length. Uterus containing numerous eggs, 38–39 × 17–19. Excretory pore terminal. Excretory vesicle Y-shaped. Details of its organization could not be examined due to overlap with other organs.

Remarks

Paracryptotropaperuviana clearlybelongswithintheCryptotropidae based on its morphological characteristics and the results of our molecular phylogenetic analysis ( Fig. 1 ). At the same time, the phylogenetic analysis strongly suggests that Pa. peruviana represents an independent genus-level lineage ( Fig. 1 ). Paracryptotropa peruviana differs from sequenced representatives of other cryptotropid genera by 4.7%–7.7% of nucleotide positions in the partial 28S gene ( Table 2 ) and by 19.0%–20.3% in the partial cox1 gene ( Table 3 ).

Morphologically, the new genus is most similar to members of Cryptotropa and Pseudocryptotropa . The new genus differs significantly from species of Cryptotropa in the position of the copulatory pouch and the genital pore. Unlike Pa. peruviana , the copulatory pouch in members of Cryptotropa are nearly or entirely preacetabular, and the genital pore is very close to the less margin of the body. In the new genus, the genital pore is submedian, very close to the less caecum. The new genus can be differentiated from Pseudocryptotropa most easily in the position and orientation of the copulatory pouch. In the new genus, the copulatory pouch is oriented longitudinally and is mostly overlapping with the ventral sucker, whereas in Pseudocryptotropa it is transversally oriented, with only the proximal end of the copulatory pouch sometimes slightly reaching the ventral sucker. Eggs in Pa. peruviana lack polar filaments characteristic of members of Pseudocryptotropa .

The new genus differs from Cephalouterina in several morphological characteristics. With the exception of the metraterm, the uterus in Pa. peruviana does not extend anteriorly past the level of ventral sucker bifurcation, whereas in Cephalouterina it reaches oral sucker. The testes in the new genus are situated more posteriorly than in Ce. dicamptodoni . Vitelline follicles in the new genus extend posterior to the testes and reach the posterior end of the body, whereas in Ce. dicamptodoni they barely reach the level of the posterior margin of the testes.

The new genus differs from Renschetrema , Rohdetrema and Armadoatrium (see Discussion and diagnosis below) in a number of morphological features, the most obvious being the lack of the stylet and stylet sac.

Thus, a combination of molecular phylogenetic evidence and morphology strongly suggests that Pa. peruviana represents a new genus within the Cryptotropidae . The diagnosis of the new genus is provided below.

Figures

Figure 1. Phylogenetic relationships among 32 taxa of the Microphalloidea resulting from Bayesian analysis of partial sequences of the 28S ribosomal DNA gene. Posterior probabilities> 80% are shown above internodes.Species sequenced in the present paper are in bold. Branch length scale bar indicates the number of substitutions per site. Abbreviations of digenean families:Col, Collyriclidae; Cry, Cryptotropidae; Lec, Lecithodendriidae; Mic, Microphallidae; Pha, Phaneropsolidae; Ple, Pleurogenidae; Pro, Prosthogonimidae; Sto, Stomylotrematidae. Abbreviations for geographical regions: IM, Indo‐Malayan realm; NT, Neotropical realm.

Figure 5. Position of copulatory pouch in the four new species described in this study. A, Cryptotropa acanthosauri. B, Pseudocryptotropa surniculi. C, Pseudocryptotropa testilobata. D, Paracryptotropa peruviana.

Figure 8. Paracryptotropa peruviana. Ventral view of the holotype.