Pseudocryptotropa testilobata Tkach, Chermak & Greiman, 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 : 545-546

Pseudocryptotropa testilobata Tkach, Chermak & Greiman sp.nov.

( Figs 5C , 6C, D )

Type host: Microhierax erythrogenys Vigors, 1831 ( Aves: Falconidae ).

Site in host: Small intestine.

Type locality: Occidental Mindoro Province, Mindoro Island, Philippines.

Type material: The type series consists of 10 mature specimens deposited in the HWML. Holotype (marked on a slide containing three specimens): HWML 216830, labelled ex. Microhierax erythrogenys , small intestine, Occidental Mindoro Province, Mindoro Island, Philippines, 10 July 2013, coll. S. Greiman. Paratypes: HWML 216831 (lot of three slides), labels identical to the holotype .

GenBank sequences: Oº534010 (ribosomal), Oº469315 (cox1).

ZooBank registration: urn:lsid:zoobank.org:act:729890FCBF37-49B5-9B32-57C573725937 .

Etymology: The name of the new species reflects its most characteristic morphological feature, the strongly lobed testes.

Description (based on 10 adult specimens; measurements of holotype given in text; measurements of entire series given in Table 5 ): Body 584 long, broad, flaưened, with rounded anterior end and either blunt or somewhat concave posterior end; body width at level of ventral sucker 425. Body length-to-body width ratio 1.4. Forebody 262. Tegument armed with minute spines densely covering entire body with the exception of a small area around excretory pore. Oral sucker subterminal, rounded, 90 × 103. Ventral sucker round, 75 × 83. Oral sucker width-to-ventral sucker width ratio 1.2. Prepharynx indistinct; pharynx rounded, 39 × 37. Oesophagus 79, about two times longer than pharynx. Caecal bifurcation immediately anterior to ventral sucker; caeca short, terminating approximately at level of posterior margin of ventral sucker and anterior margin of testes.

Two testes, opposite, longitudinally elongated, strongly lobed, immediately postacetabular, reaching anteriorly level of mid-section of ventral sucker. Right testis 230 × 130, less testis 219 × 126. Copulatory pouch long, 211 × 43, antero-sinistral to ventral sucker, transversally oriented. Proximal end of copulatory pouch overlaps anterior margin of ventral sucker; distal end curves towards dorsal surface in hook-like manner. Copulatory pouch contains winding seminal vesicle, prostatic gland and ejaculatory canal; evaginated cirrus not observed. Genital pore dorsal, extracaecal, near posterior end of less caecum.

Ovary 101 × 127, distinctly lobed, slightly overlapping with ventral sucker, dextral to it. Seminal receptacle voluminous, 144 × 86, situated between testes, immediately posterior to ovary. Mehlis’ gland and Laurer’s canal not observed. Vitellarium extensive, in the form of numerous, small, irregularly shaped follicles largely arranged in two transverse fields, one in anterior half of body between oral sucker and anterior margins of testes, and another at posterior end of body, immediately posterior to testes, slightly overlapping their posterior margins. A few vitelline follicles can be situated in middle third of body between two main fields.

Uterus ventral to gonads, mostly in middle third of body, expanding laterally to margins of the body on both sides and reaching posteriorly between testes to level of mid-length of the testes. Metraterm well defined, could not be measured in holotype. Uterus contains numerous eggs, 38–41 × 16–18. Eggs possess polar filaments on each pole of the egg. Polar filaments consist of several fibres aưached/glued together. Excretory pore terminal. Excretory vesicle Y-shaped, with short stem and short arms reaching level of posterior margin of seminal receptacle.

Remarks

Pseudocryptotropa testilobata clearly belongs to Pseudocryptotropa based on its morphological characteristics including the dorsal genital pore, the position of gonads, copulatory pouch and uterus, in addition to the general body shape. It is morphologically similar to Ps. macrotestis and to Ps. surniculi described in the present work. Pseudocryptotropa testilobata can be differentiated easily from both these species by having strongly lobed testes and a lobed ovary and a substantially longer oesophagus ( Fig. 6 ; Table 5 ). Pseudocryptotropa testilobata also differs from Ps. surniculi by having straight distal portion of the copulatory pouch (curved in Ps. surniculi ). Besides, Ps. testilobata and Ps. surniculi differ by 2.2% of nucleotide positions in the sequenced fragment of the nuclear ribosomal ITS + 28S regions and 9.1% of nucleotide positions in the sequenced fragment of the mitochondrial cox1 ( Tables 2 , 3 ). These levels of divergence are significant and clearly indicate species-level differences, especially considering that the specimens were collected from the same locality.

Khotenovsky (1965) synonymized the monotypical genus Novetrema Rohde, 1962 with Pseudocryptotropa , stating their high morphological similarity without providing a detailed comparison between the two genera. This taxonomic decision was preserved in the Keys to the Trematoda (Lotz and Font 2008b). We re-examined syntypes of Novetrema nycticebi Rohde, 1962 deposited in the collection of the Natural History Museum, London (no. 1962.1.24.2). Unlike species of Pseudocryptotropa , the genital pore in N. nycticebi is ventral. Eggs of the two new species of Pseudocryptotropa descibed in the present work have well-developed polar filaments, whereas eggs of N. nycticebi lack filaments. Therefore, we resurrect Novetrema as an independent genus, which remains temporarily in the family Phaneropsolidae until DNA sequences of N. nycticebi become available.

New morphological characters found in the two new species of Pseudocryptotropa described in the present work require amendments in the diagnosis of the genus (syn. Novetrema Rohde, 1962 ).

Figures

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 6. New species of Pseudocryptotropa. A, Pseudocryptotropa surniculi, ventral view of the holotype. B, P. surniculi, testes of a paratype. C, Pseudocryptotropa testilobata, ventral view of the holotype. D, P. testilobata, testes of a paratype.