Orostylis timucuorum, GOBERT, STEFAN, ARMONIES, WERNER, DIEZ, YANDER L., JOUK, PHILIPPE, MONNENS, MARLIES, REVIS, NATHALIE, REYGEL, PATRICK, SMITH, JULIAN III, STEENKISTE, NIELS VAN & ARTOIS, TOM, 2022

GOBERT, STEFAN, ARMONIES, WERNER, DIEZ, YANDER L., JOUK, PHILIPPE, MONNENS, MARLIES, REVIS, NATHALIE, REYGEL, PATRICK, SMITH, JULIAN III, STEENKISTE, NIELS VAN & ARTOIS, TOM, 2022, Orostylis gen. nov., a new genus of Dalytyphloplanida with seven new species (Platyhelminthes: Rhabdocoela), Zootaxa 5115 (1), pp. 29-46 : 37

Orostylis timucuorum sp. nov. Smith III

( Figs 3H , 5 , S 1–S 3 )

Localities. Small beach facing the intracoastal waterway near the boat launch and pier, Whitney Marine Laboratory, FL (29°40’14”N; 81°12’57”W) Muddy sand with oyster shells and shell fragments (May 21, 2019): Type locality. Bear Island , NC (approximately 34°38’51”N; 77°07’02”W) Muddy sand-flat near tidal drainage stream (Jun., 2018). Outer sandy beach on Bogue Banks, Emerald Isle Site, NC (34°38’42”N; 77°05’23”W) Surface sediment halfway between MTL and LTL (Mar. 15, 2013). “Anne McCrary’s Mudflat” (muddy sand-flat facing the intracoastal waterway near Wilmington, NC —approximately 34°13’11”N; 77°48’49”W) (Jan. and Feb., 1970) by R. M. Rieger. Bogue Inlet, NC. Shallow subtidal in “ Amphioxus sand” (date unknown) by R. M. Rieger.

Material. Five specimens studied alive; two turned into whole mounts; one designated holotype ( FMNH KV.696); the other reference material (HU XIV.3.19); three specimens examined by confocal microscopy; three live-drawings made by R. M. Rieger .

Etymology. The specific epithet is in honour of the people (called “Timucua” by the Spanish) who first inhabited the region near the type locality.

Description. Living, sexually mature specimens from the type locality measure 705–895 µm long; all specimens possess a pair of pigmented eyes, as well as the general characters of the genus ( Fig. 5A ). The pharynx averages 16% of the body length ( Fig. 5A : ph; n = 3). The pharynx bears 6 club-tipped, distal tentacles ( Figs. 5A inset, S1). Radial pharyngeal musculature is thickly arranged and pseudostriated ( Fig. 5B : rm). The male organ is directed forward and lies just behind or beside the pharynx; testes are paired ( Figs. 5A : t, S2). The ovary is V-shaped, with paired germinal zones, sometimes giving the impression of two ovaries ( Figs. 5A,C : ov). The vitellarium is either very large, or paired, situated immediately behind the ovary and extending posteriorly ( Fig. 5C : vit). A bursal tissue lies in the ventral midline at approximately the level of the ovaries ( Fig. 5A,D : bu). Confocal microscopy reveals a musculature associated with this that appears to lead to a mid-ventral pore ( Figs. 5D,E : red arrow). The 58-µmlong stylet ranges in length from 47 to 69 µm (n = 5), possessing a flared base with two distinct areas ( Figs. 3H , 5F–G; 5H : sb, st). The stylet appears to have separate pathways for sperm and prostatic secretions. The stylet has a lateral slit that extends at least partway along it ( Fig. 5F , arrows). Squeezing apparently flattens a stylet that, at rest, comprises a base with an elongate, semi-circular tip whose point rests in a small “cup” ( Fig. 5H : green arrow); the base and tip are in nearly orthogonal planes ( Fig. 5H : red arrows). Connection of the male canal with the pharynx tube could not be confirmed with the material at hand.

Figures

FIGURE 1. Sampling localities of Orostylis gen. nov. Symbols represent the respective species described in this work, as indicated in the figure legend.

FIGURE 3. Drawings of the stylets of the new species of Orostylis gen. nov. included in this work. A. Orostylis dohae sp. nov. B–C. Orostylis asinaraensis sp. nov. D. Orostylis caecus sp. nov. E. Orostylis donanae sp. nov. F. Orostylis gallicus sp. nov. G. Orostylis distortus sp. nov. H. Orostylis timucuorum sp. nov. All drawings are from the holotypes, except for C and D which are from reference material. The stylets are oriented with the proximal base pointing to the top and the distal tip pointing to the bottom of the plate.

FIGURE 5. Orostylis timucuorum sp. nov. Anterior is to the left in A–E, to the top in F–H. A. Squeezed live specimen from the type locality, showing positions of major organs. Inset: anterior margin of pharynx showing six club-like pharyngeal tentacles; drawing by R.M. Rieger. B. Single confocal frame through the pharynx, showing pseudostriated radial muscles. C. Lateral view of specimen from the type locality, showing relative locations of ovary and vitellaria. D. Confocal stack showing the ventral midline with bursa and associated body-wall musculature (DNA-magenta, Muscle actin-green). E. Higher magnification of bursal area, showing bursa with foreign sperm, and bursal pore (red arrow). F. Heavily squeezed stylet of specimen from the type locality, showing general structure and slit along distal portion (arrows). G. Stylet of whole-mounted specimen by R.M. Rieger from Anne McCrary’s mudflat, sample 394, 1.29.1970. Same scale as F. H. Stylet in situ from a lightly squeezed specimen from the type locality. Note that the two portions of the stylet base are curved upward (red arrows), and semicircular stylet tip is in a plane perpendicular to that of the base, and that its pointed tip rests in a cup-like depression (green arrow).