Brachyrhynchoides ortizi Diez & Sanjuan & Monnens & Artois 2023, sp. nov.
Creators: name: Diez, Yander L.
name: Sanjuan, Claudia
name: Monnens, Marlies
name: Artois, Tom
Publisher: name: Zenodo
Year: 2023
Subjects: Biodiversity
Taxonomy
Animalia
Platyhelminthes
Rhabdocoela
Polycystididae
Brachyrhynchoides
Brachyrhynchoides ortizi

description: Brachyrhynchoides ortizi sp. nov.
urn:lsid:zoobank.org:act: 774F2120-7B24-4F35-82EE-C46D93D9D9A7
Figs 1A, D–F, 2A, E, Table 1
Diagnosis
Species of Brachyrhynchoides Artois & Schockaert, 2013 with the prostatic stylet type IV tubular, ~70 µm long, ~15 µm wide proximally, distally slightly narrower; terminal aperture oblique. Accessory stylet I tubular, 70 µm long; accessory stylet II needle-shaped, 59 µm long.
Etymology
Species named after Dr Manuel Ortiz (Marine Research Centre, Havana University, Cuba), prominent Cuban marine researcher, for his outstanding contribution to the knowledge of marine invertebrates, mainly crustaceans.
Material examined
Holotype CUBA • 1 whole mount; Santiago de Cuba, Siboney; 19°57′34″ N, 75°42′07″ W; 7 Feb 2019; depth 2 m; sublittoral, coarse-grained sand with fragments of calcareous algae, salinity 34 ‰; https://id.luomus.fi/KV.697; FMNH.
Other material CUBA • 1 whole mount; same collection data as for holotype; photographs of live specimens available; HU XIX.1.46.
Description
The live specimens are unpigmented (Fig. 2A), ~ 1.5 mm long. The proboscis (Figs 1A, 2A: pr) measures less than 10% of the body length. A pair of eyes (Figs 1A, 2A: e) is located caudally to the proboscis. The pharynx (Figs 1A, 2A: ph) is located in the anterior body half.
A pair of testes (Figs 1A, 2A: t) is located caudally to the pharynx. The prostatic stylet type IV (Figs 1A, 2A, 2E: ps4; 1D) is tubular, 68–71 µm long (x = 70 µm; n = 2) and 12–17 µm wide proximally (x = 15 µm; n = 2); distally, it is slightly narrower, with the terminal aperture oblique. The accessory stylet I (Figs 1A, 2A, E: as1; 1E) is tubular, 70 µm long (n = 1), 4 µm wide proximally (n = 1), and 2 µm wide distally (n = 1); its terminal aperture is oblique. The accessory stylet II (Figs 1A, 2E: as2; 1F) is needle-shaped, 59 µm long (n = 1), and 3 µm wide proximally (n = 1); it is slightly curved in the distal half and ends in a pointing tip. The proportions between the stylets were calculated following the methods of Artois et al. (2013): α = (length of the accessory stylet I / length of the prostatic stylet) × 100 = 98–103%; β = (length of the accessory stylet II / length of the prostatic stylet) × 100 = 83–87%; γ = (length of the accessory stylet II / length of the accessory stylet I) × 100 = 84%.
The vitellaria (Figs 1A, 2A: vi) run at the body sides, from just behind the pharynx to almost the caudal end of the body. The left vitellarium was much smaller than the right one but this may be caused by of squeezing or orientation of the animal. The ovaries (Fig. 1A: ov) are oval-shaped, located rostrally to the stylets; only a single oocyte was observed in each ovary.
Remarks
The new species, Brachyrhynchoides ortizi sp. nov., shows the diagnostic features of the genus, as listed by Artois et al. (2013): the proboscis is very small (less than 10% of the body length) and three stylets occur in the male atrial organs (a prostatic stylet type IV, an accessory stylet I, and an accessory stylet II). However, these features need revaluation as Tessens et al. (2014) showed the genus to be paraphyletic. Three species of Brachyrhynchoides were known until now: B. triplostylis Artois & Schockaert, 2013, B. acutus Artois & Schockaert, 2013, and B. oosterlyncki Willems, Reygel & Artois, 2013, which can be distinguished by differences in stylet morphology (Artois et al. 2013).
The prostatic stylet type IV of B. ortizi sp. nov. is the shortest and widest with respect to that of its congeners (see Table 1). It is more similar in length to that of B. oosterlyncki; however, the prostatic stylet of B. ortizi is straight, slightly wider proximally (15 µm) than distally, and with the distal aperture oblique, whereas in B. oosterlyncki the stylet is 8 µm wide proximally and tapers to a distally-pointing tip. The other two species of Brachyrhynchoides have a much larger prostatic stylet (see Table 1). Furthermore, in B. triplostylis and B. acutus, the prostatic stylet is curved and gradually tapers to a sharp (B. acutus) or rounded (B. triplostylis) tip (Artois et al. 2013).
According to Artois et al. (2013), the accessory stylet I in species of Brachyrhynchoides is connected to the larger accessory vesicle. However, no accessory vesicles were observed in B. oosterlyncki and, therefore, the authors considered the shorter stylet to be accessory stylet I. For comparative purposes, we will consider accessory stylet I the larger in all species. In B. ortizi sp. nov., the tubular accessory stylet I is 70 µm long, with the terminal aperture oblique, and more or less of the same width over its entire length. On the other hand, the accessory stylet I in B. oosterlyncki is shorter, needle-shaped, and wider proximally. The accessory stylet I of B. triplostylis and B. acutus is much larger (Artois et al. 2013) (see Table 1).
The accessory stylet II in all species of Brachyrhynchoides is needle-shaped. The smallest stylet appears in B. oosterlyncki, followed by B. ortizi sp. nov., and it is much larger in B. triplostylis and B. acutus (see Table 1). The accessory stylet II of B. ortizi is slightly curved and its distal half ends in a pointed tip. It is similar in morphology to what is described for other species, with the exception of B. acutus, where the accessory stylet II is distinctly curved. The proportions between stylets vary greatly interspecifically (Table 1, see Artois et al. 2013).
description: Published as part of Diez, Yander L., Sanjuan, Claudia, Monnens, Marlies & Artois, Tom, 2023, New species of Polycystididae (Platyhelminthes: Kalyptorhynchia) from Cuba and the Pacific coast of Panama, pp. 67-86 in European Journal of Taxonomy 856 on pages 70-71, DOI: 10.5852/ejt.2023.856.2029, http://zenodo.org/record/7554565