Mariplanellidae Ax & Heller, 1970

Van Steenkiste, Niels W. L. & Leander, Brian S., 2022, The molecular phylogenetic position of Mariplanella piscadera sp. nov. reveals a new major group of rhabdocoel flatworms: Mariplanellida status novus (Platyhelminthes: Rhabdocoela), Organisms Diversity & Evolution (New York, N. Y.) 22 (3), pp. 577-584 : 579

Mariplanellidae Ax & Heller, 1970 , status novus.

We change the status of the subfamily Mariplanellinae Ax & Heller, 1970 (Dalytyphloplanida, Trigonostomidae ) to the taxon Mariplanellida status novus and its only family, Mariplanellidae status novus, based on the results of the molecular phylogenetic analyses (see Discussion).

Type species: Mariplanella frisia Ax & Heller, 1970 .

Amended diagnosis: Rhabdocoela with pharynx rosulatus, compact paired vitellaria, unpaired ovary and paired testes. Female system with efferent (female duct) and afferent (bursa, muscular spermatic duct, seminal receptacle, insemination duct) connection between ovary and common genital atrium. Male system with sclerotized stylet.

Mariplanella Ax & Heller, 1970

Diagnosis: see Ax and Heller (1970)

Mariplanella piscadera Van Steenkiste & Leander , sp. nov.

Type material: The only specimen was used for genomic DNA extraction; therefore, the DNA voucher becomes the holotype (BBM MI4941, extracted DNA in buffer stored at -80 °C).

Other material: Images of the live specimen.

Type locality: Piscaderabaai , Curaçao (12°07′17.5"N 68°58′09.4"W). Coarse sand enriched with organic material at about 2.5 m deep .

Etymology: The species epithet refers to the type locality.

Diagnosis: Species of Mariplanella with a curved stylet consisting of a proximal funnel surrounded by a thick collar, a tapering distal spiral and a sclerotized connection supporting the bend of the stylet.

Description: The animal was only about 0.35 mm long, and its pharynx rosulatus (ph, Fig. 1a ) was at about ¾ of its body length. Eyes were absent. Two types of adenal rhabdite glands were present in its anterior end: (1) needle-shaped rhabdites 3–4 μm long (rh1, Fig. 1b–c ) and densely concentrated in the anterior tip, forming a central dark patch that partly envelops the oval brain and stretches toward the sides of the body, and (2) bundles of long viscous strands (rh2, Fig. 1b ) that run obliquely from the anterior dark patch toward the sides of the body.

A few details of the atrial organs were visible in the live individual. Posterior to the pharynx, an interconnected larger and smaller dark mass likely corresponds to the sperm-containing bursa (bu, Fig. 1d ) and seminal receptacle (sr, Fig. 1d ), respectively. The stylet (st, Fig. 1d ; Fig. 1e ) consisted of a funnel-shaped proximal tube surrounded by a thick collar and that curved backwards into a spiralling distal tip. The bend was reinforced with a sclerotized connection between the proximal tube and the distal spiral. The axial length of the stylet was about 38 μm.

Figures

Fig.1 LM images of the live specimen and stylet drawing of Mariplanella piscadera sp. nov. from Curaçao. (a) Full specimen with the pharynx visible as a lighter round outline in the posterior part of the body. (b–c) Detail of the anterior end showing the brain and two types of adenal rhabdite glands (rh1, red overlay; rh2, blue overlay). (d) Detail of the posterior end behind the pharynx show-