Bathyspadella oxydentata, Miyamoto & Nishida, 2011

Miyamoto, Hiroomi & Nishida, Shuhei, 2011, A new deep-sea benthopelagic chaetognath of the genus Bathyspadella (Chaetognatha) with ecological and molecular phylogenetic remarks, Journal of Natural History 45 (45 - 46), pp. 2785-2794 : 2788-2790

publication ID	https://doi.org/ 10.1080/00222933.2011.602806
persistent identifier	https://treatment.plazi.org/id/B4763A4C-FFBB-6B7E-FE6D-9279A86EFEAB
treatment provided by	Felipe
scientific name	Bathyspadella oxydentata
status	sp. nov.

Treatment

Bathyspadella oxydentata View in CoL sp. nov.

( Figures 1 View Figure 1 and 2 View Figure 2 ; Table 1)

Type material

Holotype. Sagami Bay , central Japan, 35 ◦ 00’ N; 139 ◦ 20’ E, 1400– 1200 m depth, 7 July 2005; body length, 14.2 mm; NSMT-ch28. GoogleMaps

Paratypes. Six specimens (body length, 10.2–15.5 mm) from Sagami Bay in May, July and November 2005 ( Table 1); NSMT-ch29 – NSMT-ch34. All specimens are preserved in vials in 5% formaldehyde / seawater.

AG (B)

(A)

(C)

(D)

(F)

1 mm

anterior teeth

Description

Body robust, rigid, opaque ( Figure 1A View Figure 1 ). Maximal body length of specimens without tail fin 15.5 mm ( Table 1). Ventral ganglion large and swollen. Musculature well developed. Tail segment representing 38–44% (average 40.8%) of body length without tail fin. Transverse musculature in trunk. Posterior margin of the transverse musculature accords with the posterior margin of ventral ganglion. A pair of lateral fins, representing c. 40% of body length without tail fin, touching the anterior margin of seminal vesicle ( Figure 1A,F View Figure 1 ). Rayless-zone absent. Tail fins round, touching seminal vesicle. Remains of collarette adhering on the neck and seminal vesicle. Gut colour, vivid orange, but colour lost after long preservation. Eyes round, lacking pigment ( Figure 1B,C View Figure 1 ). Eyes structured in two layers. Lens round, located on centre of eye. Gland canals from the end of the head to the neck, with L-shape ( Figure 1A,B View Figure 1 ). A total of 9–13 hooks without serration ( Table 1). Bent zero to four posterior teeth ( Figure 2 View Figure 2 ) and two to four anterior teeth, shorter than posterior ones. Apical gland cell complex on top of head ( Figure 1A View Figure 1 ). Vestibular organs swollen with micro-spines, shallow notches at the external margin ( Figure 2 View Figure 2 ). Five large eggs in each ovary. Opening of seminal receptacle forming a capsule ( Figure 1D View Figure 1 ). No ovarian sac to hold the ova. Seminal vesicle round with a spermatic duct on top ( Figure 1E,F View Figure 1 ).

Molecular phylogeny

Papillon et al. (2006) reported that chaetognaths have two paralogous 18S rRNA genes (Class I and Class II). In the present study, the Class I sequence was obtained from the new species ( Figure 3A View Figure 3 ). The Class I sequences of 20 species were analysed: one Bathyspadella , ten Sagittidae , two Spadellidae , two Eukrohnidae , one Krohnittidae , one Pterosagittidae and three Heterokrohnidae sense Casanova, 1999. The Class II sequences were set as the outgroup of the tree. The lineage of Class I consisted of four distinct groups (Groups A–D). Bathyspadella oxydentata was included in Group D, which included Xenokrohnia sorbei , Heterokrohnia davidi and Heterokrohnia longicaudata with strong statistical support ( Figure 3A View Figure 3 ). The 16S rRNA phylogeny was also composed of four groups (Groups E–H), of which Group H was formed by B. oxydentata , H. longidentata and H. davidi ( Figure 3B View Figure 3 ).