Pasipha atla, Negrete, Lisandro & Brusa, Francisco, 2016
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publication ID |
https://doi.org/ 10.11646/zootaxa.4137.2.2 |
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publication LSID |
lsid:zoobank.org:pub:94661073-A6EB-4134-B709-BF4ED7AF50EA |
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DOI |
https://doi.org/10.5281/zenodo.6070963 |
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persistent identifier |
https://treatment.plazi.org/id/03F24A30-FFCB-FF99-98FA-EEC209C5FF61 |
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treatment provided by |
Plazi |
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scientific name |
Pasipha atla |
| status |
sp. nov. |
Pasipha atla View in CoL sp. nov.
( Figs. 1–4 View FIGURE 1 View FIGURE 2 View FIGURE 3 View FIGURE 4 )
Pasipha sp. 2: Negrete et al. 2014a
Type material. Holotype: MLP-He 6173. San Antonio Strict Nature Reserve, Misiones Province, Argentina, 29.X.2008, L. Negrete, coll.; cephalic region: transverse sections on 11 slides (7 µm); anterior region at level of ovaries: sagittal sections on 26 slides (7 µm); pre-pharyngeal region: transverse sections on 6 slides (6 µm); pharynx and copulatory apparatus: sagittal sections on 31 slides (7 µm).
Paratypes: MLP-He 6461–1. Urugua-í Wildlife Reserve, Misiones Province, Argentina, 22.VIII.2009, L. Negrete, coll.; cephalic region and anterior region at level of ovaries: transverse sections on 35 slides (8 µm); prepharyngeal region: transverse sections on 4 slides (8 µm); pharynx and copulatory apparatus: sagittal sections on 35 slides (8 µm). MLP-He 6461–2. Urugua-í Wildlife Reserve, Misiones Province, Argentina, 22.VIII.2009, L. Negrete, coll.; cephalic region: sagittal sections on 20 slides (8 µm); anterior region at level of ovaries: sagittal sections on 32 slides (8 µm); pre-pharyngeal region: transverse sections on 5 slides (8 µm); pharynx and copulatory apparatus: sagittal sections on 26 slides (8 µm).
Diagnosis. Dorsum dark brown with a whitish median stripe only present on the cephalic and posterior body regions. Eyes dorsal with clear halos. Pharynx cylindrical. Prostatic vesicle extrabulbar, tubular, with narrow lumen, and proximally forked. Male atrium twice the length of the female atrium, highly folded. Proximal part of male atrium with small folds. Ovaries anterior to the anteriormost testes. Distal sections of ovovitelline ducts ventral to the female atrium, joining behind it. Common ovovitelline duct vertical and posterior to the female atrium, and female genital canal antero-dorsally flexed. Female atrium with folded walls.
Type locality. San Antonio Strict Nature Reserve (26° 03’ S, 53° 46’ W), Misiones Province, Argentina.
Etymology. The scientific name is a combination of the initials of Urugua-í Wildlife Reserve park managers Ariel Tombo and Laura Aréjola, in gratefulness of their valuable assistance during fieldwork.
External morphology. The body is elongate with parallel margins. In living specimens, the anterior region gradually narrows, with blunt ending, and the posterior region is sharply pointed ( Fig. 1 View FIGURE 1 A, B). The dorsal colour pattern is homogeneous dark brown ( Fig. 1 View FIGURE 1 A). A thin whitish median stripe is distinguished in the cephalic region, extending to about 5 mm from the anterior tip ( Fig. 1 View FIGURE 1 B), and close to the posterior tip (only visible under stereomicroscope). The ventral surface is greyish. After fixation, the dorsal colour pattern is light brown ( Fig. 1 View FIGURE 1 B, C). The eyes, with clear halos, surround the anterior tip and extend uniserially on both body margins along 3–5 mm from the anterior tip, continuing bi- and tri-serially for 2–4 mm ( Fig. 1 View FIGURE 1 A, C). Then the eyes extend pluriserially over the dorsal surface. At the pharyngeal level they become restrict to the body margins and less numerous, and extend to the posterior end. Length of the fixed specimens ranged from 35 to 48 mm, maximum width was 2.4–5.4 mm, and maximum height 1.5–2.2 mm. The mouth was located at a distance of 66–78% from the anterior tip, and the gonopore at 77–88% ( Table 1 View TABLE 1 ).
Internal morphology. Epidermis, secretions and musculature in the cephalic region. Dorsal epidermis (20–25 µm µmhigh) receives abundant rhabditogen and erythrophil fine granular secretions, and erythrophil and cyanophil amorphous secretions in less quantity. Ventral epidermis (30 µm high), ciliated in the creeping sole (~90% of body width), receives the same type of secretions. Sensory pits (20–25 µm deep), as simple invaginations, contour the anterior tip and spread on both body margins in a single row up to ~ 7 mm from the anterior tip. The cutaneous musculature has the same arrangement (see below) and similar thickness (10% to 15% of body height) as in the pre-pharyngeal region. The parenchymatic musculature is composed of the same layers as the pre-pharyngeal region, ranging from 5% to 10% of body height ( Fig. 2 View FIGURE 2 A). There is no musculo-glandular specialization in the cephalic region.
Epidermis, secretions and musculature in the pre-pharyngeal region. Abundant rhabditogen cells with erythrophil secretion, numerous cells with fine granular and amorphous erythrophil secretions, and fine granular cyanophil secretion in less quantity discharge through dorsal epidermis (25–30 µm high) and body margins ( Fig. 2 View FIGURE 2 C, E). Ventral epidermis (30 µm high), ciliated in the creeping sole (85–90% of body width), presents abundant small dermal rhabdites densely arranged at the apex of cells. Also, abundant amorphous cyanophil and fine granular erythrophil secretions, and less numerous amorphous erythrophil secretion are present in ventral epidermis ( Fig. 2 View FIGURE 2 D). There is no glandular margin ( Fig. 2 View FIGURE 2 B, E).
The cutaneous musculature consists of the three typical layers of Geoplaninae , a thin circular subepidermal layer, with the same thickness dorsally and ventrally, followed by an intermediate layer with diagonal fibres, and an internal thicker longitudinal layer arranged in bundles, which is thicker ventrally than dorsally ( Table 2 View TABLE 2 ). CMI ranges from 9% to 15%. Parenchymatic musculature is composed of three layers: a dorsal layer with decussate fibres (situated below the longitudinal cutaneous layer), which is the thickest, a supra-intestinal and a sub-intestinal transverse layer ( Fig. 2 View FIGURE 2 B, C). Dorso-ventral fibres are arranged among intestinal branches. PMI ranges from 4% to 7% ( Table 2 View TABLE 2 ).
Digestive system. The pharynx (1.2–1.6 mm in length, about 3–4% of body length) is cylindrical, with the dorsal insertion slightly posteriorly displaced (100–350 µm) ( Fig. 2 View FIGURE 2 F). The mouth is located in the posterior third of the pharyngeal pouch ( Fig. 2 View FIGURE 2 F). The epithelium lining of the outer surface of the pharynx is cuboidal and densely ciliated, and the outer pharyngeal musculature is arranged in two layers: a thin longitudinal subepithelial layer (5– 7.5 µm thick) followed by an inner circular layer (10–25 µm thick). The epithelium lining the pharyngeal lumen is columnar and ciliated, and the inner pharyngeal musculature consists of a circular subepithelial layer (10–50 µm thick) followed by a subjacent longitudinal layer (15–50 µm thick). Secretory cells, the cell bodies of which are located anterior and lateral to the pharynx, discharge abundant erythrophil and cyanophil fine granular secretion in the pharyngeal epithelium ( Fig. 2 View FIGURE 2 F).
The oesophagus (100–600 µm in length) ( Fig. 2 View FIGURE 2 F) is lined by a columnar epithelium followed by a subjacent circular muscle layer (15–25 µm thick) and a longitudinal layer (10–15 µm thick). The oesophagus: pharynx ratio ranges from 19% to 32%.
Male reproductive system. The testes, ovoid in shape, are arranged in two to four irregular rows on each side of the body, being dorsal to the intestinal branches and located below the supra-intestinal parenchymatic muscle layer ( Fig. 2 View FIGURE 2 B). Testes occupy 11–13% of the body height. They appear behind the ovaries and extend to the prepharyngeal region, being located at a distance between 21–27% and 61–75% of the body length from the anterior end ( Table 3 View TABLE 3 ). The sperm ducts are located among fibres of the sub-intestinal parenchymatic muscle layer or just below them, being slightly dorsal and medial to ovovitelline ducts in the pre-pharyngeal region ( Fig. 2 View FIGURE 2 B). Behind the pharynx, sperm ducts are tortuous and distally dilated ( Fig. 3 View FIGURE 3 ) with lumen full of spermatozoa. In the vicinity of the common muscle coat, sperm ducts bend toward the dorsum and forward, and open into the proximal region of the extrabulbar prostatic vesicle ( Figs. 3 View FIGURE 3 , 4 View FIGURE 4 B). The prostatic vesicle, located just behind the pharynx ( Figs. 2 View FIGURE 2 F, 3), is tubular with a narrow irregular lumen and presents two anatomically and histologically distinguishable regions (see below) ( Figs. 3 View FIGURE 3 , 4 View FIGURE 4 A–C). The proximal region is proximally forked, communicating with sperm ducts ( Figs. 3 View FIGURE 3 , 4 View FIGURE 4 A– C). The distal region is ventro-posteriorly curved and opens into the ejaculatory duct exactly at the boundary of the common muscle coat ( Figs. 3 View FIGURE 3 , 4 View FIGURE 4 A, D). The ejaculatory duct is sinuous and opens into the bottom of the male atrium, sometimes slightly displaced ventrally ( Figs. 3 View FIGURE 3 , 4 View FIGURE 4 D). The walls of the most proximal part of the male atrium present numerous small folds ( Figs. 3 View FIGURE 3 , 4 View FIGURE 4 A, D, E) while the rest of the atrium is a cavity with large folds. Thus, its lumen is narrow ( Figs. 3 View FIGURE 3 , 4 View FIGURE 4 A). The male atrium is approximately twice the length of the female atrium ( Table 3 View TABLE 3 ).
Sperm ducts are lined by a ciliated cuboidal epithelium surrounded by a circular muscle layer (5 µm thick). The prostatic vesicle is lined with ciliated columnar epithelium, traversed in its proximal region by abundant fine granular pale cyanophil secretion, and abundant coarse granular erythrophil secretion in its distal region ( Fig. 4 View FIGURE 4 A– D). The glandular cell bodies are located in the surrounding parenchyma laterally and anteriorly to the prostatic vesicle. The prostatic musculature of both regions comprises intermingled longitudinal and circular fibres (25–55 µm thick). The ejaculatory duct is lined by a ciliated columnar epithelium, which receives scarce fine granular cyanophil secretion, followed by a subjacent muscular layer with circular fibres intermingled with some longitudinal fibres (10–20 µm thick).
The lining epithelium of the small folds of the most proximal part of the male atrium is columnar and ciliated, with the apex of the cells filled with strongly stained fine granular erythrophil secretion ( Fig. 4 View FIGURE 4 E). The epithelium of the rest of the male atrium is cuboidal and non-ciliated except in the distal portion, which is columnar. The male atrium receives abundant fine granular cyanophil secretion along its entire length, and in its middle third also receives abundant fine granular erythrophil secretion ( Fig. 4 View FIGURE 4 F, G). Cell bodies of both types of glands are located below the epithelial lining of the atrium. The muscularis consists of a subepithelial circular layer (10–25 µm thick) followed by a longitudinal layer (5–10 µm thick). Longitudinal fibres, forming a not well organized coat (40–100 µm thick) (named eigenmusculatur by Graff (1899); here named intermediate muscle fibres), are located between the muscularis and the common muscle coat ( Figs. 3 View FIGURE 3 , 4 View FIGURE 4 A). The common muscle coat consists of longitudinal and less abundant circular and oblique fibres, thicker dorsally (20–50 µm thick) than ventrally (10–20 µm thick).
Female reproductive system. The ovaries (300–500 µm in length, 200–400 µm high), ovoid in shape, are situated at a distance of 13–22% of the body length from the anterior end ( Fig. 2 View FIGURE 2 G, Table 3 View TABLE 3 ). They are located between the sub-intestinal parenchymatic muscle layer and the nervous plate ( Fig. 2 View FIGURE 2 G). The ovovitelline ducts emerge from the medial dorsal side of the ovaries, and run posteriorly, being located just above the nervous plate in the pre-pharyngeal region ( Fig. 2 View FIGURE 2 B, G). Their distal sections are located ventrally to the female atrium. Just behind this atrium, they contour the common muscle coat and run to the sagittal plane in a slight ascending course. The ovovitelline ducts join behind the atrium to form a common glandular ovovitelline duct ( Figs. 3 View FIGURE 3 , 4 View FIGURE 4 H). It is almost vertically oriented and distally curves forward, passing through the common muscle coat, and opens into the female genital canal ( Figs. 3 View FIGURE 3 , 4 View FIGURE 4 H). The latter continues ascending and opens into the bottom of the female atrium, dorsally displaced ( Fig. 3 View FIGURE 3 , 4 View FIGURE 4 H). The female atrium presents folded walls, although it is not as richly folded as the male atrium ( Figs. 3 View FIGURE 3 , 4 View FIGURE 4 A). At the level of the gonopore there is a dorsal fold that separates the atria ( Fig. 3 View FIGURE 3 ).
The ovovitelline ducts are lined with a ciliated cuboidal epithelium, followed by a circular muscle layer (5 µm thick). Both the distal portions of the ovovitelline ducts and the common glandular ovovitelline duct receive abundant secretion from the shell glands ( Figs. 3 View FIGURE 3 , 4 View FIGURE 4 A, H). The lining epithelium of the latter, which also receives scarce fine granular cyanophil secretion, is columnar and ciliated followed by a circular muscle layer (10 µm thick). The female canal is lined by a non-ciliated columnar epithelium, which receives abundant fine granular cyanophil secretion ( Fig. 5 View FIGURE 5 I). The muscularis of the female canal consists of circular and longitudinal intermingled fibres (10–20 µm thick). Like the female canal, the lining epithelium of the female atrium is columnar and nonciliated, but in the latter, the apical part of the epithelium is filled with abundant fine granular erythrophil and cyanophil secretions ( Fig. 4 View FIGURE 4 J). In the distal portion of the female atrium erythrophil secretion is more abundant. Cell bodies of these glands are subepithelial, located in the surrounding parenchyma within the common muscle coat. The muscularis of the female atrium consists of a thin layer of intermingled circular and longitudinal fibres (5–10 µm thick). There is a thick muscle layer with intermingled circular and some longitudinal and oblique fibres (35–100 µm thick) (here named intermediate muscle fibres) located between the atrial muscularis and the common muscle coat ( Figs. 3 View FIGURE 3 , 4 View FIGURE 4 A). The common muscle coat consists of longitudinal fibres, thicker dorsally (35–50 µm thick) than ventrally (15–25 µm thick). Vitellaria are well developed in all specimens. At the pre-pharyngeal level, vitelline follicles are arranged dorsally and ventrally to the intestinal branches and among them ( Fig. 2 View FIGURE 2 B).
Parasitism. Nematode larvae were found in all study specimens, located in the parenchyma among intestinal branches and vitellaria of the anterior body region.
TABLE 1. Measurements (mm) of fixed specimens of Pasipha atla sp. nov. (DG) distance of gonopore from anterior end, (DM) distance of mouth from anterior end, (DMG) distance between mouth and gonopore. The numbers in parentheses represent the position relative to body length (%).
| MLP-He 6173 | MLP-He 6461–1 | MLP-He 6461–2 | |
|---|---|---|---|
| Length | 35.3 | 42 | 35 |
| Maximum width | 2.6 | 2.4 | 5.4 |
| Maximum height | 1.5 | 1.6 | 2.2 |
| DM | 27.5 (78%) | 32 (76%) | 23 (66%) |
| DG | 30 (85%) | 37 (88%) | 27 (77%) |
| DMG | 2.5 | 5 | 4 |
| Creeping sole (%) | 90% | 90% | 90% |
TABLE 2. Thickness of cutaneous (CM) and parenchymatic (PM) musculatures (µm), and CMI and PMI indices at prepharyngeal region of Pasipha atla sp. nov.
| MLP-He 6173 | MLP-He 6461–1 | MLP-He 6461–2 | |
|---|---|---|---|
| CM dorsal | |||
| circular | 2.5 | 5 | 5 |
| diagonal | 10 | 12.5 | 17.5 |
| longitudinal | 60 | 75 | 62.5 |
| CM ventral | |||
| circular | 2.5 | 5 | 5 |
| diagonal | 15 | 25 | 32.5 |
| longitudinal | 85 | 125 | 80 |
| CMI (%) | 12% | 15% | 9% |
| PM dorsal | 30 | 40 | 50 |
| PM supra-intestinal | 25 | 35 | 25 |
| PM sub-intestinal | 25 | 30 | 25 |
| PMI (%) | 5% | 7% | 4% |
TABLE 3. Measurements (mm) of reproductive organs of Pasipha atla sp. nov. LCGD, length of common glandular ovovitelline duct; LFA, length of female atrium; LFC, length of female canal; LMA, length of male atrium; LPV, length of prostatic vesicle. The numbers in parentheses represent the position relative to body length (%).
| MLP-He 6173 | MLP-He 6461–1 | MLP-He 6461–2 | |
|---|---|---|---|
| Anteriormost testes | 7.5 (21%) | 12 (29%) | 9.4 (27%) |
| Posteriormost testes | 24.7 (70%) | 31.5 (75%) | 21.4 (61%) |
| LPV (proximal) | 0.6 | 0.85 | 0.95 |
| LPV (distal) | 0.6 | 0.9 | 1.2 |
| LMA | 3 | 3.25 | 2.5 |
| Location of ovaries | 4.5 (13%) | 9.2 (22%) | 7.6 (22%) |
| LCGD | 0.35 | 0.6 | 0.6 |
| LFC | 0.35 | 0.37 | 0.4 |
| LFA | 1.2 | 2 | 1.1 |
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