Phonorhynchoides lalanai 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
Phonorhynchoides
Phonorhynchoides lalanai

description: Phonorhynchoides lalanai sp. nov.
urn:lsid:zoobank.org:act: 94BB22AE-7C11-4ECB-A344-B8ACFB01CF28
Figs 1C, I–J, 2D, G, Table 2
Phonorhynchoides sp. in Leasi et al. 2018: 1–12.
Diagnosis
Species of Phonorhynchoides Beklemischev, 1927 with a prostatic stylet type IV ~114 µm long, proximally ~9 µm, narrowing to 5 µm wide distally; it is twisted in the middle. Accessory stylet type IV 105–106 µm long, narrowing from 4–5 µm wide proximally to 2 µm wide distally; slightly curved in the proximal half.
Etymology
Species named after the late Dr Rogelio Lalana (Marine Research Centre, Havana University, Cuba), prominent Cuban marine researcher, awarded with the National Prize of Marine Sciences of Cuba in 2012, for his outstanding contribution to the knowledge of marine invertebrates, mainly crustaceans.
Material examined
Holotype CUBA • 1 whole mount; Santiago de Cuba, Bueycabón; 19°57′38″ N, 75°57′28″ W; 6 Feb 2018; depth 0.5 m; sublitoral, fine-grained sand rich in organic matter, salinity 33 ‰; https://id.luomus.fi/KV.699; FMNH.
Other material PANAMA • 2 whole mounts; Pacific Ocean, Isla Iguana; 07°38′06″ N, 79°59′48″ W; 6 Mar. 2016; depth 10 m; sublittoral, coarse sand with gravel, covered with organic matter; HU XIX.1.49–XIX.1.50.
Description
The specimens are unpigmented (Fig. 2D), ~ 1 mm long. The proboscis (Figs 1C, 2D: pr) is less than 10% of the body length. A pair of eyes is located just behind the pharynx (Figs 1C, 2D: e). The pharynx (Figs 1C, 2D: ph) is positioned in the anterior body half.
A pair of testes (Fig. 1C: t) is located posterior to the pharynx. The prostatic stylet type IV (Figs 1C, 2G: ps4, 1I) is 110–120 µm long (x = 114 µm; n = 3) and narrows from a width of 8–11 µm proximally (x = 9 µm; n = 3) to 5 µm distally (n = 3); the distal end is rounded. At about midway, the prostatic stylet is twisted. The accessory stylet type IV (Figs 1C, 2G: as4, 1J) is 105–106 µm long (n = 3), slightly curved in the proximal half, and narrows from 4–5 µm wide proximally (n = 3) to 2 µm wide distally (n = 3); the distal end is oblique and sharp.
The vitellaria (Fig. 1C: vi) run from just behind the pharynx to the caudal body end. The female bursa (Fig. 1C: b) is located beside the stylets; it is muscular but not bipartite. The ovaries (Fig. 1C: ov) are located rostrally to the stylets; they are more or less kidney-shaped, with the oocytes organised in a row; the oocytes distally increase in diameter.
Remarks
Phonorhynchoides lalanai sp. nov. exhibits the diagnostic features of Phonorhynchoides: the prostatic stylet type IV is larger than the accessory stylet type IV, and the female bursa is muscular but not bipartite (Willems et al. 2017).
The prostatic stylet of P. lalanai sp. nov. is twisted at the end of its proximal half, while this structure is never twisted in the other six known species of the genus. For comparison, the prostatic stylet is undulated in P. carinostylis Ax & Armonies, 1987 and P. gondwanae Willems & Artois in Willems et al., 2017, corkscrew-shaped in the middle in P. somaliensis Schockaert, 1971, and almost straight in P. flagellatus Beklemischev, 1927, P. japonicus Ax, 2008, and P. minor Diez, Sanjuan, Reygel & Artois in Diez et al., 2018b (for details see Willems et al. 2017; Diez et al. 2018b). Furthermore, the prostatic stylet carries ornamentations in P. carinostylis (spiral ridge over the whole length) and P. japonicus (thickened proximally and short spiral ridge), which are missing in P. lalanai. In P. lalanai, the prostatic stylet is distally rounded, differing from that in P. minor (terminally oblique) and the other species (sharp tip). The prostatic stylet of P. lalanai. (~114 µm) is considerably longer than that of P. minor (53–58 µm), but shorter than that in the other species (see Table 2).
The accessory stylet type IV of P. lalanai sp. nov. ends in an oblique tip, while it ends in a pointed tip in all other species of Phonorhynchoides. The accessory stylet of the new species (105–106 µm) is smaller than that of P. gondwanae and P. japonicus, but larger than that of the other species (see Table 2). The length proportion between the accessory stylet type IV and the prostatic stylet type IV is larger in the Caribbean species (P. lalanai 88–95%, P. minor 78–85%) than in their known congeners (Willems et al. 2017; Diez et al. 2018b) (see Table 2). Indeed, it is characteristic of P. lalanai and P. minor that the prostatic stylet and accessory stylet are similar in length. The distinct morphology of the sclerotised stylets, previously discussed, warrants the status of P. lalanai as a new species.
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 75-76, DOI: 10.5852/ejt.2023.856.2029, http://zenodo.org/record/7554565