Harana harai Almeida & Álvarez-Presas & Carbayo 2023, SP. NOV.
Creators: name: Almeida, Ana Laura
name: Álvarez-Presas, Marta
name: Carbayo, Fernando
Publisher: name: Zenodo
Year: 2022
Subjects: Biodiversity
Taxonomy
Animalia
Platyhelminthes
Tricladida
Geoplanidae
Harana
Harana harai

description: HARANA HARAI ALMEIDA & CARBAYO SP. NOV.
(FIGS 17–19)
Zoobank registration: urn: lsid: zoobank. org:act: AC02BCF9-C45D-41AD-BBBC-D1589201E570
Holotype: MNHNCL PLAT-15042 (Field code, F4738): Parque Nacional Bosque Fray Jorge, Región de Coquimbo, Chile (30°39′′45.0′′S, 071°40′′57.4′′W). coll. F. Carbayo et al., 4 December 2010. Cephalic region: transverse-to-horizontal sections on two slides; a portion behind the cephalic region: horizontal sections on three slides; pharynx and copulatory apparatus: sagittal sections on eight slides.
Type locality: Parque Nacional Bosques de Fray Jorge, Chile. Species only known from this locality.
Etymology: The specific epithet pays homage to Prof. Marcos Ryotaro Hara (University of São Paulo).
Description
External aspect: The live specimen measured approximately 8 mm long and 1 mm wide when creeping. The length of the preserved specimen was 6.5 mm long, while its width was 1.2 mm. The body is elongated and subcylindrical, with the anterior tip rounded and the posterior tip pointed (Fig. 17A). The creeping sole is 78% of body width in the prepharyngeal region, as measured from sagittal sections. The mouth is positioned at a distance from the anterior extremity of the body equivalent to 83% of the body length; the gonopore 92%.
The dorsal colour of the live specimen consists of numerous grey-brown (RAL 8019) dots mottling the pearl-beige (RAL 1035) ground colour (Fig. 17A). The ventral side is pearl-beige, darker in the anterior tip.
The eyes are of a single pigmented cup measuring 25 µm in diameter. Clear haloes around the eyes are absent. The eyes are distributed in a single row that encircles the anterior tip of the body and extends marginally until the posterior tip. The sensory pits are 25 µm deep and are distributed in a single row ventrolateral along a body portion with about 8% of the body length.
Internal morphology: Numerous rhabditogen cells and two types of gland cells producing erytrophil and cyanophil granules, respectively, pierce the dorsal epidermis of the pre-pharyngeal region. Other gland cells discharge their fine erythrophil granules through the ventral epidermis. A glandular margin is absent. All of these gland cells are scarce in the cephalic region.
The cutaneous musculature consists of a thin subepithelial layer of circular muscle, followed by a thin layer of decussate fibres and an innermost layer of longitudinal muscle comprising bundles of two to four fibres each. The longitudinal layer is 4 µm thick dorsally and 8 µm ventrally. The thickness of cutaneous muscle relative to the body height is 2.3%. The cutaneous musculature in the cephalic region is thinner.
The parenchymal musculature is weak. A parenchymal layer of transverse subintestinal fibres is relatively well developed (Fig. 18B), while other muscle layers are lacking. Instead, dorsal diagonal fibres and transverse supraintestinal fibres are scattered. The ventral nerve plate is poorly defined.
A straight tube (Fig. 18A, B) runs medially among the fibres of the subintestinal parenchymal layer of transverse muscle. The tube runs from the near anterior tip of the body and is at least 1 mm long. The body portion behind the cephalic region was denatured for DNA extraction, and eventual communication of this tube with other organs could not be observed. The tube is 25 µm in diameter and is lined with a weakly stained cuboidal epithelium. A thin longitudinal muscle underlies the lining epithelium of the tube.
The pharyngeal pouch extends over the copulatory apparatus and extends 750 µm behind it (Fig. 19B, C). The pharyngeal pouch is approximately twice as long as the pharynx. The anteriormost portion of the pharynx was denatured, but its general appearance is that of a cylindrical type (Fig. 18C). The posterior portion of the pharynx lies over the prostatic vesicle. The outer pharyngeal epithelium is underlain by a layer of longitudinal muscle (5 µm thick), followed by a layer of circular fibres (17 µm) and an innermost layer of longitudinal muscle (8 µm); the inner pharyngeal epithelium is underlain by a layer of circular muscle (12 µm), followed by a layer of longitudinal muscle (5 µm) (Fig. 19A).
Testes were not found in the sections. The sperm ducts are located over the main nervous system and contain sperm in their distal portion. These ducts communicate laterally with the respective branch of the prostatic vesicle (Fig. 19B). The extrabulbar prostatic vesicle is tubular. The prostatic vesicle has the shape of an inverted J in lateral view and its distal portion penetrates the anterior region of the welldeveloped penis bulb. The prostatic vesicle is lined with ciliated, cuboidal epithelium. This epithelium is crossed by gland cells producing erythrophil granules and is surrounded by a circular muscle (10 µm thick). The ejaculatory duct is horizontal and slightly sinuous and opens at the tip of the penis papilla. The ejaculatory duct is lined with ciliated, cuboidal epithelium and is surrounded by a 3 µm thick circular muscle.
The penis papilla is cylindrical, having a distal enlargement that makes the papilla resemble a club (Fig. 19B–E). The papilla lies horizontally and occupies the entire male atrium. The proximal two-thirds of the penis papilla are lined with a columnar epithelium, while the epithelium of the enlarged, distal-third is cuboidal. Three types of gland cells discharge their erythrophil, cyanophil and light cyanophil granules, respectively, through the covering epithelium of the penis papilla. The erythrophil type is particularly abundant along the proximal two-thirds of the papilla. The cyanophil type is restricted to the dorsoproximal region of the penis papilla, while the light cyanophil type is found only at the tip of the penis papilla. The lining epithelium of this organ is underlain by a layer (5 µm thick) of circular muscle, followed by a layer of longitudinal fibres (5 µm).
The male atrium is smooth, except for some small folds close to the insertion of the penis papilla. The communication of the male atrium with the female atrium is narrowed by a thin fold located dorsally to the level of the gonopore (Fig. 19B–E). The male atrium is lined with a squamous epithelium dorsally and with a columnar epithelium ventrally. This ventral epithelium is pierced by the necks of gland cells producing erythrophil granules. The atrial epithelium is underlain by a layer (2 µm thick) of circular muscle, followed by a layer (3 µm thick) of longitudinal muscle, the latter underlying only the ventral epithelium.
The ovaries were not found in the sections available. Vitellaria are abundant around the intestine. The ovovitelline ducts run backward above the ventral nerve plate. Posterior to the gonopore canal, these ducts ascend medially inclined to unite with the common glandular ovovitelline duct below the female atrium (Fig. 19B, C, E). This common duct ascends posterior to the female atrium to join the female genital canal. This canal projects posteroventrally from the posterodorsal portion of the female atrium (Fig. 19B).
The female atrium to male atrium length ratio is 2.5: 4.0. The female atrium is irregular in shape and is inclined toward the gonopore.This atrium is lined with a columnar, 100 µm high epithelium and the apical portion of its cells is erythrophil (Fig. 19E). Toward the gonopore canal, the columnar epithelium passes gradually into a cuboidal type. Two types of gland cells producing fine cyanophil and scarce erythrophil granules, respectively, pierce the epithelium of the female atrium. The atrial epithelium is underlain by a longitudinal muscle (2 µm thick), followed by a circular muscle (8 µm). A weak common muscle coat of longitudinal fibres wraps the male and the female atria.
Remarks on the new tribe Haranini and its genus: H a r a n a i s a l way s r e t r i e v e d a s a n in g r o u p o f Geoplaninae sister to Timymini. The extraordinarily long pharyngeal pouch of Harana harai precludes it from being fitted in any of the tribes except Timymini. Moreover, H. harai and Timyma share a sister-group relationship in all analyses, and it is reasonable to ponder that the long extension of the pharyngeal pouch in both taxa is homologous. Such a pharyngeal pouch extending posteriorly over the copulatory apparatus is only known in these two species among all the land planarians.
In addition to the long pharyngeal pouch, Haranini and Timymini are morphologically different from each other in that the cephalic region is semi-lunate in Timymini (vs. regular in Haranini), and the sensory pits are intercalated with sensory papillae (vs. sensory papillae absent in Haranini). The ventral position of the testes in Timymini, a condition which is an exception within Geoplanini, unfortunately could not be checked in H. harai since the body region seemingly housing the testes of this small animal was removed for DNA extraction. This same constraint impeded tracking the complete course of the straight tube level with the subintestinal transverse parenchymal muscle. On the other hand, the tube is a feature which is only found in Haranini.
description: Published as part of Almeida, Ana Laura, Álvarez-Presas, Marta & Carbayo, Fernando, 2023, The discovery of new Chilean taxa revolutionizes the systematics of Geoplaninae Neotropical land planarians (Platyhelminthes: Tricladida), pp. 837-898 in Zoological Journal of the Linnean Society 197 (4) on pages 861-863, DOI: 10.1093/zoolinnean/zlac072, http://zenodo.org/record/7813977