Manotrema, Preez & Domingues & Verneau, 2022

Preez, Louis Heyns du, Domingues, Marcus Vinícius & Verneau, Olivier, 2022, Classification of pleurodire polystomes (Platyhelminthes, Monogenea, Polystomatidae) revisited with the description of two new genera from the Australian and Neotropical Realms, International Journal for Parasitology: Parasites and Wildlife 19, pp. 180-186 : 185

4.2.2. Genus: Manotrema n. g

4.2.2.1. Generic characteristics. Polystomatidae . Polystomoidinae . Mouth with false oral sucker subterminal. Muscular pharynx. Intestinal caeca extending full length of body proper, not confluent posteriorly. Testis single, compact equatorial. Ovary pretesticular, small. Vitellaria throughout most of body proper, not extending into haptor. Vaginae latero-ventral in line with anterior margin of testis. Uterus absent. Haptor with deep incisions between suckers, which appear fingerlike. Skeletal elements in suckers not arranged as a ring of blocks but rather thin spatulate outward bending needles. Sucker type IV. Two small pairs of hamuli present with very deep cuts between handle and guard. Parasitic in urinary bladder of pleurodires of the Neotropical Realm.

4.2.2.2. Taxonomic summary. Etymology: The haptor with deep cuts between the suckers resembles a hand with fingers.

Type species: Manotrema uruguayensis (Man´e-Garzon´and Gil, 1961) n. comb. Synonym: Polystomoides uruguayensis Man´e-Garz´on and Gil, 1961. Site of infection: urinary bladder.

Other species: Manotrema fuquesi (Man´e-Garzon´and Gil, 1962) n. comb. Synonym: Polystomoides fuquesi Man´e-Garzon´and Gil, 1962. Site of infection: urinary bladder; Manotrema brasiliensis (Viera, Novelli, Sousa and SouzaLima, 2008) n. comb. Synonym: Polystomoides brasiliensis Viera, Novelli, Sousa and SouzaLima, 2008 . Site of infection: urinary bladder.

4.3. What does sucker morphology within Manotrema n. g. suggest about functionality?

The deep cuts and the outwards directed suckers resemble the branchial generation of two polystome genera infecting anuran hosts, namely Polystoma Zeder, 1800 and Metapolystoma Combes, 1976 . When an oncomiracidium of these polystomes establishes on the gills of a young tadpole, well before metamorphosis, it develops rapidly and produces eggs in a matter of 16 days ( Kok and Du Preez, 1989; Du Preez and Kok, 1998). This parasite, which is usually considered as a neotenic form, attaches to the branchial filaments inside the branchial chamber of the tadpole. Its haptor shows deep incisions between suckers, increasing flexibility of the haptor. Furthermore, suckers are not directed ventrally like in mature parasites found in the bladder of their host, but ventro-laterally, making attaching to gill filaments within a tightly packed gill chamber challenging. Therefore, one could argue that the deep cuts between the suckers in Manotrema n. g. may also provide additional flexibility to the suckers. However, their functional adaptations require further investigation.