Lineid Heteronemerteans (Nemertea: Pilidiophora) from Sagami Bay, Japan, with Some Proposals for the Family-Level Classification System

Figure 3 from: Ellison CI, Frey MR, Sanford E, Maslakova S (2024) Ribbon worms (phylum Nemertea) from Bodega Bay, California: A largely undescribed diversity. ZooKeys 1204: 15-64. https://doi.org/10.3897/zookeys.1204.117869

“…The phylum is known to possess large numbers of cryptic species, that is, morphologically indistinguishable, but nevertheless distinct, species (e.g., Chen et al 2010;Leasi and Norenburg 2014;Hao et al 2015;Hiebert and Maslakova 2015a). Given that morphological approaches often fail to distinguish between look-alikes, DNA-based approaches are increasingly used to identify and delimit species, resolve phylogenies, and infer biogeographical patterns (e.g., Chernyshev et al 2021a;Mendes et al 2021;Kajihara et al 2022aKajihara et al , 2022b.…”

First eumonostiliferous nemertean from the Nishi-Shichito Ridge, Genrokunemertes obesa gen. et sp. nov. (Eumonostilifera, Nemertea)

“…Nemerteans (or ribbon worms) are usually marine, benthic invertebrates, inhabiting intertidal to hadal depths ( Chernyshev & Polyakova, 2018 ). Although about 1,300 species have been recognized in the phylum ( Kajihara, 2017 ), dozens of species have been turned out to be new to science in five years (e.g., Chernyshev & Polyakova, 2018 ; Chernyshev & Polyakova, 2019 ; Hookabe et al, 2020 ; Hookabe, Kohtsuka & Kajihara, 2021 ; Kajihara, Ganaha & Kohtsuka, 2022 ). In particular, benthic fauna of deep-sea nemerteans at great depths exceeding 1000 m is not well understood; currently, only 19 species were reported ( Chernyshev, 2013 ; Chernyshev & Polyakova, 2019 ).…”

Microscopic anatomy of the integument in the ribbon worm Micrura bella (Stimpson, 1857) (Pilidiophora, Nemertea)

“…The cutis, found only in Heteronemertea, is traditionally used in the taxonomy of this order at the generic level (e.g., R. Gibson, 1985; Riser, 1993). However, few studies have been devoted to the ultrastructure of the epidermis and cutis of heteronemerteans (Anadón, 1974; Gontcharoff & Lechenault, 1966; Oaks, 1978; Storch & Welsch, 1972), and focused on Lineus sanguineus str., Lineus ruber (Müller, 1774), and L. viridis (Müller, 1774) (= L. gesserensis [Müller, 1774]), belonging to the phylogenetic Lineage H (Kajihara et al, 2022). A complete description of the epidermis and cutis has not been provided for these species, and only a few gland types have been identified.…”

“…Here, we describe the ultrastructure of the epidermis and cutis of the heteronemertean Micrura bella (Stimpson, 1857) and compares it with that of L. ruber and L. viridis integuments described in the literature. M. bella belongs to the basal phylogenetic Lineage A (Kajihara et al, 2022; Schwartz, 2009) and may have more plesiomorphic states in the structure of the integument than species from L. sanguineus . str.…”

“…Lineage H (Kajihara et al, 2022). A complete description of the epidermis and cutis has not been provided for these species, and only a few gland types have been identified.…”