Orostylis dohae, 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 : 31-33

publication ID	https://doi.org/ 10.11646/zootaxa.5115.1.2
publication LSID	lsid:zoobank.org:pub:E78C0947-2E8A-4663-A428-9303E84D6924
DOI	https://doi.org/10.5281/zenodo.6346925
persistent identifier	https://treatment.plazi.org/id/3BC5FEA0-2560-478C-A9E6-53F01AB5DAE5
taxon LSID	lsid:zoobank.org:act:3BC5FEA0-2560-478C-A9E6-53F01AB5DAE5
treatment provided by	Plazi
scientific name	Orostylis dohae
status	sp. nov.

Treatment

Orostylis dohae sp. nov. Gobert, Van Steenkiste & Artois

( Figs. 2 View FIGURE 2 , 3A View FIGURE 3 , 4D View FIGURE 4 )

Neodalyellida n. gen. n. sp. 2 in Van Steenkiste et al. (2013)

Neodalyellida sp. 2 in Stephenson et al. (2019)

Localities. Doha, Qatar (25°19’04”N; 51°32’18”E) Sand at about the high-water mark (Mar. 19, 2008): Type locality GoogleMaps .

Material. Observations on live specimens. One whole mount designated holotype ( FMNH KV.690), and two serially sectioned specimens (HU XIV.3.04– XIV.3.05) .

Etymology. Species named after the capital of Qatar, where the species was discovered.

Description. Animals are about 0.6 mm long (measured on whole mount), with two dark brown, kidney-shaped eyes ( Figs. 2A View FIGURE 2 , 4D View FIGURE 4 : e). The epidermis is syncytial, strongly ciliated, and 2–5 μm thick. The cilia measure 2–3 µm. Nuclei in the epidermis are scarce. A thin basal membrane underlies the epidermis, followed by a circular and a longitudinal muscle layer, respectively. Several basophilic, coarse-grained glands are situated in the anterior end of the body, in the area surrounding the mouth. The caudal end of the body contains eosinophilic cement glands.

The mouth is located near the anterior end of the body ( Fig. 2A View FIGURE 2 : m) and surrounded by a sphincter. A long, thin-walled oral tube connects the mouth opening to the pharynx. The pharynx ( Figs. 2 View FIGURE 2 , 4D View FIGURE 4 : ph) is located in the anterior body half and is between 1/4 and 1/5 of the body length long. The pharynx is cylindrical in shape, with a conspicuous musculature, including radial, circular, and longitudinal muscles. This is typical for the pharynx doliiformis in neodalyellids, but the radial muscles are very wide and stacked closely together with little or seemingly no space between them. The anterior end of the pharynx bears a “collar” ( Fig. 2A View FIGURE 2 : phc) separated by a constriction from the rest of the pharynx. This collar is provided with three pairs of tentacles projecting anteriorly ( Figs. 2A View FIGURE 2 , 4D View FIGURE 4 : pht). The intestine ( Fig. 2B View FIGURE 2 : i) lies caudally from the ovary ( Fig. 2 View FIGURE 2 : ov). In live specimens, diatom frustules were observed inside the intestinal tract.

The large, paired testes are situated just anterior to the midbody ( Figs. 2 View FIGURE 2 , 4D View FIGURE 4 : t), behind the pharynx, on either side of the body. In live specimens, two distinct testes were clearly observed. However, in the serial sections, the separation between both testes was less obvious, creating the impression of a single, large testis. The two testes lie against one another in such a way that the spermatogenic distal ends of the testes point laterally.A pair of vasa deferentia extend anteriorly and connect the testes to the seminal vesicle ( Figs. 2 View FIGURE 2 , 4D View FIGURE 4 : sv) in the proximal half of the male copulatory organ. The copulatory organ is situated in the anterior part of the body, alongside the pharynx. It consists of the round to ovoid seminal vesicle ( Figs. 2 View FIGURE 2 , 4D View FIGURE 4 : sv), followed distally by a small, globular prostate vesicle ( Fig. 2B View FIGURE 2 : pv) filled with eosinophilic gland secretions. The seminal and prostate vesicle are lined with a syncytial, nucleated epithelium and surrounded by circular muscles. In the distal half of the copulatory organ, the seminal vesicle connects directly to a sclerotised stylet ( Figs. 2 View FIGURE 2 , 4D View FIGURE 4 : st; 3A). The stylet is a simple, thin-walled funnel, curved at an angle of about 90° at its midpoint. The stylet is 33 µm long and 9 µm wide proximally. It connects to a long male duct, which opens in the oral cavity ( Fig. 2B View FIGURE 2 : oc).

The female genital system consists of a large, curved ovary ( Fig. 2 View FIGURE 2 : ov), positioned at the midbody, dorsally to and in front of the intestine. A female duct or gonopore was not observed. Instead, the oviduct appears to connect directly to the intestinal lumen. It is assumed that eggs are deposited in the intestinal lumen and expelled from the body via the mouth. Eosinophilic glands are present in the region where the ovary connects to the intestine. In the same area, vesicles with sperm were observed in the intestinal wall ( Fig. 2A View FIGURE 2 : isv). Possibly, these vesicles are resorptive and function as a bursa. The posterior half of the body is almost completely taken up by a lobed or branched vitellarium ( Fig. 2B View FIGURE 2 : vit).