Cratera anamariae Carbayo

Carbayo, Fernando & Almeida, Ana Laura, 2015, Anatomical deviation of male organs of land planarians from Rio de Janeiro, Brazil, with description of two new species of Cratera (Platyhelminthes, Tricladida), Zootaxa 3931 (1), pp. 27-40 : 34-39

Cratera anamariae Carbayo , sp. nov.

Etymology. The specific name pays homage to Ana Maria Leal-Zanchet (Universidade do Vale do Rio dos Sinos, São Leopoldo, RS, Brazil), for her contribution to the knowledge of the triclads.

Type material. All specimens collected in Parque Nacional da Serra dos Órgãos, municipality of Teresópolis/ RJ, Brazil by F. Carbayo et al. Holotype PL 1567 (field number, F2557): (S 22o27'19", W 42o59'51"). 8/Jul/2008. Anterior end: sagittal sections on 12 slides; portion containing testes: horizontal sections on 10 slides; prepharyngeal region: transverse sections of 7 slides; pharynx and copulatory apparatus: sagittal sections on 23 slides. Paraype PL 1566 (field number, F1337): (S 22o27'19", W 42o59'51"). 19/Dez/2007. Anterior end: sagittal sections on 16 slides; portion containing the ovaries: horizontal sections on 10 slides; pre-pharyngeal region: transverse sections of 2 slides; pharynx and copulatory apparatus: sagittal sections on 35 slides. Paratype PL 1571 (field number, F2605): (S 22o27'19", W 42o59'51"). 13/Jul/2008. Anterior end: horizontal sections on 5 slides; pharynx and copulatory apparatus: sagittal sections on 40 slides. Paratype PL 1568 (field number, F2559): (S 22o27'19", W 42o59'51"). 8/Jul/2008. Copulatory apparatus: sagittal sections on 26 slides. Paratype PL 1570 (field number, F2595): (S 22o27'19", W 42o59'51"). 8/Jul/2008. Copulatory apparatus: sagittal sections on 13 slides. Paratype PL 1572 (field number, F4190): (S 22o27'23.1", W 42o59'42.5"). 6/Jan/2010. Pharynx and copulatory apparatus: sagittal sections on 11 slides. Paratype PL 1569 (field number, F2594): (S 22o27'19", W 42o59'51"). 10/Jul/2008. Anterior end: sagittal sections on 32 slides; pre-pharyngeal region: transverse sections of 6 slides; pharynx and copulatory apparatus: sagittal sections on 28 slides.

Type-locality. Parque Nacional da Serra dos Órgãos, Teresópolis, State of Rio de Janeiro, Brazil.

Diagnosis. The species is distinguished from its congeners by the following combination of characters: yellow dorsum with two, sometimes four longitudinal dark stripes; cylindrical pharynx, with the dorsal and ventral insertion in the same transverse plane; and an anteriorly-narrowed female atrium.

External aspect. At rest the adults are up to 4 cm in length and 1 cm in width. The body is lanceolate, with both ends pointed. The body is about 1 mm in height. When creeping its movement is smooth. The dorsum is convex, the ventral side flat. The ground color is luminous yellow or sulfur yellow, with two paramedian black stripes with 1/9th to 1/5th of the body width ( Figs. 18–23 ). The stripes are thinner towards the ends of the body, joining each other anteriorly. The dorsum between these stripes may be cream colored or light pink. The margins of the anteriormost 5 mm are black. Two submarginal, black brown stripes may also be present throughout the body. The ventral side is cream in color, becoming dark along the margins of the anteriormost 5 mm. In the six fixed, mature specimens, the mouth lies at a distance from anterior tip equal to 70–80% (mean 77%) of body length; the gonopore, 84–94% (mean 89%).

The eyes are of the pigmented-cup type, 35 µm in diameter. They are distributed from the very anterior tip back to the very posterior end. From the very anterior end, they spread over the dorsum on a band with one third of the body width, i.e., they lie beneath the lateral dark stripes ( Fig. 24 ). Those under pigmented stripes are surrounded by clear halos in the fixed specimens.

The sensory pits are distributed ventro-marginally in a single row from the very anterior tip of the body posteriorly to an extension of 29% of body length. The creeping sole is as wide as 90% of body width at the prepharyngeal region.

The epidermis is ciliated only in the creeping sole. In the pre-pharyngeal region the dorsal epidermis is pierced by rhabditogen cells and cells containing erythrophilic granules. The ventral epidermis is crossed by cells containing erythrophilic granules, scarce rhabditogen cells and scarce cyanophilic glands. There is a conspicuous glandular margin constituted of gland cells of three types, one containing erythrophilic granules, other xanthophilic granules, and a third one, scarce, producing amorphous erythrophilic secretion.

Internal morphology. The cutaneous musculature comprises the three typical layers of Geoplaninae , viz., a circular layer followed by two diagonal layers with decussate fibers, and then a longitudinal layer with fibers arranged in bundles (dorsally, 15–30 fibers each; ventrally, 25–30 fibers; ( Figs. 25–27 ). The thickness of the cutaneous muscle is 11% of body height at the pre-pharyngeal region. The three usual parenchymal muscle layers are present throughout the body: a dorsal layer of diagonal decussate fibers (15 Μm thick in the pre-pharyngeal region), a transverse supraintestinal layer (50 Μm), and a transverse subintestinal one (40 µm), the latter with its fibers more densely distributed than those of the supraintestinal layer ( Figs. 25–26 ).

Mouth situated nearly in the middle of the pharyngeal pouch ( Fig. 28 ). The pharynx is cylindrical. The pharyngeal pocket is lined with a non-ciliated epithelium. Three types of gland cells secrete through the distal pharyngeal epithelium, each producing either erythrophilic granules, or cyanophilic granules, or xanthophilic granules; the former is the most abundant. The outer and inner pharyngeal epithelia are ciliated. The outer one is underlain by a 5-µm-thick layer of longitudinal muscle fibers followed by a layer of circular fibers (5 µm). The inner epithelium is underlain by a layer of circular fibers (70 µm) followed by a layer (10 µm) of longitudinal fibers.

The testes are dorsal and located under the supraintestinal transverse muscle layer, partially interstitial to intestinal diverticula ( Figs. 26 ). They extend from 0.5 mm behind the ovaries to the level of the esophagus. The sperm ducts run between the fibers of the subintestinal muscle layer, dorsad to the ovovitelline ducts ( Fig. 26 ). Their distal portion is curved anteriorly to the sagittal plane to communicate with the paired branches of the prostatic vesicle. The branches run dorso-anteriorly. Subsequently, they continue as an unpaired portion running ventrally and posteriad to penetrate the penis bulb. The prostatic vesicle is clothed with a columnar, ciliated epithelium. It is wrapped by a 20-µm-thick layer of circular muscle. Gland cells containing fine erythrophilic granules discharge into the vesicle. The penis is of the protrusible type. The ejaculatory duct penetrates the penis papilla medially ( Figs. 29–35, 37 ). Near the tip of the papilla, the duct is widened so as to form a kind of cavity.

The ejaculatory duct is lined with a cuboidal ciliated epithelium, grading in height from 10 µm, to 20 µm in the widened portion. The conical penis papilla points dorso-posteriorly, and is clothed with a 10–15 µm high, nonciliated epithelium. It is pierced by very numerous thick-necked gland cells (4 µm in diameter), producing erythrophilic granules. Gland cells producing reddish-purple secretion discharge through the epithelium of the proximal third of the papilla. The papilla epithelium is underlain by a layer of circular muscle (12 Μm thick), followed by a layer of longitudinal muscles (5 µm).

The male and female atria are embedded in a muscularis comprising inner circular muscles (male atrium 5 µm thick, female atrium 10 µm thick) external to which is a thinner layer of longitudinal muscles (male atrium 2 µm thick, female atrium 20 µm thick). The atria are delineated anatomically by folding of their communal wall resulting in an inter-atrial aperture ( Fig. 29 ), the opening of which is about half their separate heights.

Histologically the male atrium is characterized by a non-ciliated cuboidal-to-columnar epithelium. Very abundant cyanophilic secretion is discharged through the dorsal covering epithelium, whereas through the ventral one sparse erythrophilic secretion is discharged.

The ovaries are ovoid, above the ventral nerve plate ( Fig. 38 ) and at a distance from the anterior end equal to 24% of body length. The ovovitelline ducts emerge from the dorso-external aspect of each ovary, pass posteriorly and in the proflex condition with dorsal approach, open into the female genital duct ( Figs. 29 , 36–37 ). The female atrium is ample in lateral view, but is occluded by lateral folds continued from the folding of the common atrial wall. The distal portion of ovovitelline ducts receives shell glands; the common glandular ovovitelline duct receiving these glands is markedly reduced. The female atrium is lined with a non-ciliated columnar epithelium up to 100 m in height, with a multilayered aspect, displaying vacuolation and penetrated by gland cells secreting erythrophilic granules. The length of the female atrium to male atrium ratio is about 1:1.

Remarks. Currently, the genus Cratera contains six species, namely C. crioula ( E. M. Froehlich, 1955) , C. joia ( Froehlich, 1956) , C. pseudovaginuloides ( Riester, 1938) , C. steffeni Rossi et al., 2014 , C. tamoia ( E. M. Froehlich, 1955) , and C. yara ( E. M. Froehlich, 1955) , besides C. cuarassu sp. nov. Regarding the color pattern of the dorsum, the species clearly differs from C. crioula , C. joia , C. tamoia and C. yara in that in these species the dorsum is dark excepting a narrow, pale midline. It also differs from Cratera pseudovaginuloides and C. steffeni , in that in these species the longitudinal stripes run on an orange ground color. Furthermore, in C. pseudovaginuloides the stripes are restricted to the median region, whereas in C. steffeni they are thin and nearly marginal. The new species also differs from Cratera cuarassu sp. nov. in that the ground color of the latter is only visible as a pair of submarginal light stripes on a predominant dark color.

Regarding the internal morphology, the new species differs from all other species of Cratera , namely, the dorsal insertion of the penis papilla is anterior to the ventral one, so that the organ is dorso-posteriad oriented, and the anterior portion of the female atrium is narrowed.

There are still 59 nominal species of Geoplaninae (Tyler et al., 2006–2013), the internal anatomy of which remains unknown. These species are placed under the collective genus Pseudogeoplana Ogren & Kawakatsu, 1990 . The genus was proposed for geoplaninid species inquirendae and nomina dubia ( Ogren & Kawakatsu, 1990). Six species within this group show a body color pattern consisting of one or two pairs of dark stripes on a yellowish ground, namely P. brittlebanki (Von Graff, 1897) , P. nobilis ( Von Graff, 1899) , P. o er s t e di ( Von Graff, 1899), P. perspicillata ( Von Graff, 1899) , P. rostrata ( Von Graff, 1899) and P. theresopolitana ( Schirch, 1929) .

Pseudogeoplana brittlebanki , from Tigre (near Buenos Aires, Argentina), and P. nobilis , from nearby Corral ( Chile), differ from the new species in that their paramedian black stripes are wider, 24% and 27% of the body width, respectively. Furthermore, in P. nobilis these stripes are more closely placed each other, the posterior end is red-brownish, and the ventral side presents a color pattern similar to that of the dorsum. Pseudogeoplana oerstedi , from Palermo (Buenos Aires, Argentina) differs from the new species in that its ventral body margins are brownish. Pseudogeoplana perspicillata and P. rostrata , both from Blumenau (Santa Catarina, Brazil), differ from the new species in that their lateralmost stripes are marginal and wider, and the ventral side displays a grayish lateral bands on each side of the body. Additionally, the ground color of the dorsum in P. perspicillata is dark brown-reddish, whereas in P. rostrata the pair of dark bands fades before reaching the anterior end of the body.

Unlike the original descriptions of species of Pseudogeoplana discussed earlier, P. theresopolitana was only very briefly described ( Schirch, 1929). Besides, it was described from a single specimen, the anterior end of which was lacking. The original description reads " Geoplana theresopolitana nov. spec. 30 mm in length, 4 mm in width. The cephalic end of the specimen here described is lacking. The dorsum is shiny yellow and with two black stripes with the same width. The eyes are arranged in a row, becoming scarce posteriorly. The ventral side is light, but with the help of a lens fine yellowish spots become visible. Species close to G. rostrata , even possibly identical. One specimen from Teresópolis" (original description is in Portuguese; Schirch, 1929). Schirch did not illustrate his species, but Graff did for P. rostrata . The dorsum of the latter is very similar to that of specimens of C. anamariae Carbayo , sp. nov. having a two-stripe color pattern. Thus, C. anamariae Carbayo , sp. nov. matches well the features of P. theresopolitana except for the yellowish spots on the ventral side, that are absent in the new species, and the distribution of the eyes. In regard to the latter, we are of the opinion that distribution of the eyes might not have been precisely outlined. Schirch's description subtly implied that the eyes are marginal ("arranged into a row"), but he also suggests conspecificity with P. rostrata ( Von Graff, 1899) , whose eyes are dorsal, as in the new species.

While the features of P. theresopolitana do not exclude conspecificity with C. anamariae sp. nov., they do not confirm it, either. Further investigation of Schirch's species is impracticable as the type-specimen was not found in the Museu Nacional do Rio de Janeiro (MNRJ, Rio de Janeiro, Brazil), where he was employed. It is apparently lost (Guilherme Muricy, pers. comm.). Therefore, we here describe these specimens as a new species.

Figures

FIGURES 18 – 21. Cratera anamariae sp. nov. Living specimens. (18) holotype, about 30 mm in length. (19) partial view of the ventral side of the holotype. (20) dorsal view of paratype PL 1566, about 35 mm in length. (21) dorsal view of paratype PL 1568, about 35 mm in length.

FIGURES 22 – 24. Cratera anamariae sp. nov. (22) living paratype PL 1570, about 30 mm in length. (23) wounded paratype PL 1572, as found in nature. (24) anterior end of paratype PL 1570 in ethanol.

FIGURES 25 – 28. Cratera anamariae sp. nov. Micrographs. (25) sagittal section a region anterior to the pharynx of paratype PL 1572. (26) general view of a transverse section of the pre-pharyngeal region of the holotype. (27) glandular margin of the paratype PL 1569 in a transverse section. (28) sagittal section of the pharynx paratype PL 1572. Anterior to the left.

FIGURES 29 – 33. Cratera anamariae sp. nov. Sagittal views. Anterior to the right. (29) diagrammatic reconstruction of the copulatory apparatus of the holotype. (30) micrograph of the copulatory apparatus of the holotype. (31) micrograph of the tip of the penis papilla of the holotype. (32) micrograph of the penis papilla of the holotype. (33) micrograph of the penis papilla of paratype PL 1568.

FIGURES 34 – 38. Cratera anamariae sp. nov. Sagittal views. (34) micrograph of the penis papilla of paratype PL 1566. Anterior to the left. (35) micrograph of the penis papilla of paratype PL 1566. Anterior to the left. (36) micrograph of the female genital canal and atrium of the holotype. (37) micrograph of the copulatory apparatus of paratype PL 1571. Anterior to the right. (38) micrograph of the ovary and anteriormost testis of paratype PL 1569. Anterior to the right.