taxonID	type	description	language	source
8C5F87DF8C68FFFEFF67FACF8245FE24.taxon	materials_examined	Material examined. Voucher specimen collected by M. J. Albano, 14 January 2008, Club Náutico de Mar del Plata MACN-In 38205; on mussel and ascidians, 1 – 2 m deep. Nine specimens, 19 February 2008, and one specimen, 9 May 2008, North Breakwater of the Mar del Plata harbour. Morphology. Body elongate, obovate, distally rounded; approximately 45 mm long and 23 mm wide, delicate and frail in appearance. Reddish brown dorsal surface. Absence of pigment defines many whitish oval blotches regularly distributed on the dorsal surface. A dark brown mid dorsal longitudinal stripe runs along the body covering the body bulge; with a narrow delicate black rim around the body margin (figures 1 A – 1 C). Ventral colour is paler than on the dorsal surface, with the same markings and black marginal rim (figure 1 E). The marginal tentacles are dark brown, small, pointed flaps, 15 mm long, directed forwards (figures 1 B). Numerous tentacular eyes present, scattered on the dorsal and ventral surface of the tentacles, especially near the fore margin. The cerebral eyes form a single elongated inverted-heart-shaped cluster located 25 mm from the fore margin, in a clear area above the cerebral ganglion region. With no frontal, marginal or ventral eyes spots. The pharynx is 11.5 mm long and 5.5 mm in its widest part, ruffled with five short folds and laying close behind the brain (figure 1 E). The mouth opens in the middle of the pharynx cavity. The main intestine opens distally in the pharynx cavity and runs dorsally and backwards along the body. A small rounded, whitish ventral sucker locates at about mid body. Dorsal body wall 6 – 7 µm high. The ciliated cellular epidermis has no rhabdites but with only granular pigmentation. Beneath the epidermis a frail layer of circular muscle fibres is present, underlain by a longitudinal muscle layer. Ventral body wall 10 – 11 µm high. The ciliated cellular epidermis has no rhabdites but only some scattered granular pigmentation. Beneath the well-defined basement membrane, there is a thin layer of circular muscle fibres underlain by a layer of longitudinal muscle fibres. Ovaries situated dorsally, short behind the female gonopore. The uteri are well developed (figure 1 D). The testes are ventral and distributed distally and to the sides of the uteri. The vasa deferentia run dorsal to the ovaries and ventral to the main intestine. They expand distally to form conspicuous spermiducal bulbs. The single copulatory system lies immediately behind the pharynx; it consists of a true seminal vesicle, free prostatic vesicle and a stylet (figure 2). Distally the spermiducal bulbs enter separately, though close to each other, the elongate seminal vesicle, which is 1360 µm long, 440 µm high, with a strong muscular wall. The rounded prostatic vesicle placed ventrally to the seminal vesicle. The prostatic vesicle is half as long the seminal vesicle; its muscular wall is 12 µm high, with a smooth glandular lining. The ejaculatory duct is underlain by a 10 µm high circular muscle layer, which follows a tortuous trajectory before entering the penis papilla and stylet (figure 3 A). The prostatic duct is short, straight and joins the ejaculatory duct distally at the tip of the stylet. The stylet is conical, curved, 404 µm long; four times longer than wide and directed backwards. The penis sheath and narrow male atrium are ciliated; the male gonopore opens 19 mm behind the fore margin. Uterine canals paired, without ramification. The oviducts enter the vagina separately from its posterior end. From this point, the vagina runs backwards and curves ventrally, leading to the cement pouch, which is a rounded expansion lined with a tall glandular epithelium (figure 3 B). The vagina continues ventrally and opens to a narrow female atrium and to the exterior via the female gonopore, which opens short behind the male atrium. Aside from the cement pouch, the vagina is completely ciliated. The vagina is underlain by an apparent muscular layer of circular fibres immersed in a compact eosinophilic glandular tissue. Despite the morphological homogeneity of the microanatomy of the examined specimens, some variation was detected. Although the colour pattern remains constant, the ground colour could vary from reddish-brown to dark brown, almost black (figure 1 A, 1 C). The body form varies from elongated, with rounded fore and rear margins and almost parallel lateral sides (figure 1 A) to oval, with a broad fore margin, narrowing distally (figure 1 C). Some specimens were maintained in fish tanks in the laboratory where, after five days, some fertilised eggs were deposited in an 8 by 11 mm laminar sheet, adhered to the glass wall of the tank (figure 1 F). Taxonomical discussion. Marcus (1952) described Pseudoceros mopsus from the coast of Brazil. Quiroga et al. (2004) transferred the species into genus Phrikoceros Newman & Cannon, 1996, characterized by the presence of a single male reproductive apparatus, deep marginal ruffling of the body, simple pharyngeal folds and clustered dorsal and ventral pseudotentacular eyes. Other than P. mopsus, five species of Phrikoceros were described from eastern Australia and Papua New Guinea. Although the original description of Marcus (1952) is based on a subadult specimen (not fully developed female reproductive system), the presence of marginal ruffling of the body, simple pharyngeal folds and clustered dorsal and ventral pseudotentacular eyes, as well as a single male copulatory organ with the ejaculatory and prostatic duct joining at the tip of the penis stylet characterize the species collected from Mar del Plata harbour as pertaining to Phrikoceros mopsus. Quiroga et al. (2004) did not include any description of their examined material. We find the Mar del Plata specimens differing slightly from the original description of Marcus (1952), from the described specimen from Puerto Piramides (Brusa et al. 2009) and from the diagnosis of the genus given by Newman and Cannon (1996) for the genus Phrikoceros. Our specimens are large animals ranging between 43.5 and 47.5 mm long; not moderate sized as stated in the genus diagnosis given by Newman and Cannon (1996, p. 1429). Although the species belongs to the Colour Group 4 (Newman & Cannon 1994, p. 208), this colour pattern differs slightly from the description of Marcus (1952, p. 91). Marcus’ specimens were characterized by a pattern of small sized spots covering the dorso-median region, becoming larger spots, partially fused toward the margins. The specimens from Mar del Plata had oval blotches, more or less the same size, and decreasing in number from the centre to the marginal region, without any evidence of fusion among spots. The specimen described by Brusa et al. (2009, p. 52) had a short longitudinal black line, anterior to the cerebral eye cluster that did not reached the anterior end of the body. This condition was not observed in any specimen from Mar del Plata. Newman and Cannon (1996, p. 1429) also described the tentacles of Phrikoceros as two deep ruffles or several lateral ruffles. In our material, the morphology of the tentacles is more consistent with the morphology described by the same authors for genus Pseudobiceros Faubel, 1984 (Newman & Cannon 1994, p. 209, figs. 3 C & 3 F), i. e., conspicuous ear-like pointed structures (Marcus 1952, p. 92, fig. 173). The cerebral eye cluster is on a clear area dorsal to the brain, but it is not small and rounded (Newman & Cannon 1996, p. 1431, figs. 8 & 9; Marcus 1952, p. 92, fig. 173); they look as two elongated clusters fusing toward their fore part. The pharynx of the specimens from Brazil and Mar del Plata are larger (0.25 of the body length) as compared to the description of genus Phrikoceros by Newman and Cannon (1996) (0.14 – 0.2 of the body length), and completely devoid of pigment, in opposition to the observations of Marcus (1952, p. 91). Marcus (1952) described that the ejaculatory duct and the prostatic duct join each other at the base of the penis papilla. The specimens from Argentina are instead consistent with the description of genus Phrikoceros by Newman and Cannon (1996, p. 1429) in that the ejaculatory and prostatic ducts join at the tip of the penis stylet. The sclerotised penis stylet of the specimens from Mar del Plata was neither a short, wide and straight stylet (Newman & Cannon 1996, p. 1429), nor had an undulated margin and a terminal process (Marcus 1952, p. 92), but is elongated and curved, without any unusual formation. The presence of spermiducal bulbs was not mentioned in Marcus’ description, maybe because his specimens were not fully developed (Marcus 1952, p. 93). Despite the noticed differences regarding the form of the body and the structure of the male copulatory system, the studied specimens agree with the specific features of Phrikoceros mopsus (Marcus, 1952) and confirm its generic allocation with genus Phrikoceros.	en	Bulnes, Verónica N., Albano, Mariano J., Obenat, Sandra M., Cazzaniga, Néstor J. (2011): Three Pseudocerotidae species (Platyhelminthes, Polycladida, Cotylea) from the Argentinean coast. Zootaxa 2990: 30-44, DOI: 10.5281/zenodo.202319
8C5F87DF8C6CFFF2FF67FD538373FF04.taxon	materials_examined	Examined material. Voucher: 8.0 μm sagittally sectioned specimen, mounted on 81 slides. Collected by M. J. Albano, 9 May 2008, North Breakwater of the Mar del Plata harbour. On a mussel and ascidians community, 1 – 2 m depth. MACN-In 38206. Morphology. Large, oval, 26 mm long by 15 mm wide alive, 23 mm by 14 mm preserved. Marginal tentacles formed by foldings of the fore margin, conspicuous, oriented dorsally and directed backwards, distally enlarged, with no pigmentation. Ground colour is light brown, delicately translucent in the margins, centrally yellowish brown. Round black spots cover the dorsal surface, especially in a wide marginal area. Dorsal surface covered with big bulky conical dark brown papillae, which are longer and more densely distributed to the sides of the dorsal bulge, but scattered on the bulge itself, and declining in length and number to the margins, leaving the margin free of papillae. A second area free of papillae extends from the cerebral eyes up to between the tentacle bases (figures 4 A – 4 B). Though the presence of blunt dorsal papillae gives the animal a solid appearance, the body itself is very delicate and frail. The dorsal tentacular eyespots are numerous on the dorsal surface, distributed in a single row; they are scattered ventrally. The cerebral eyespots form two separated triangular clusters. Pharynx ruffled, 320 µm long. The mouth opens at 7.2 mm from anterior margin, in the middle of the pharynx cavity. The main gut opens in the middle of the pharynx cavity roof and runs distally up to short behind the female system. Intestinal ramifications are conspicuous and numerous, running parallel to the body surface and giving out extensions into every dorsal papilla (figure 6 D). Ventral sucker at 13 mm from the fore margin of the body (figure 4 C). Dorsal body wall 50 µm high. The ciliated cellular epidermis has rhabdites and granular pigmentation. The cilia are very short, and the rhabdites and pigmentation are abundant and more densely packed on the papillae, but they are scattered on the dorsal epidermis. Beneath the epidermis a frail layer of circular muscle fibres is present, followed by a longitudinal muscle layer. The granular pigmentation is present in the epidermis and the circular muscle layer. Ventral body wall 70 µm high. The cilia are numerous and longer than those on the dorsal epidermis. Ventral surface with scarce rhabdites and no granular pigmentation. Beneath a well defined basement membrane, a thin layer of circular muscle fibres is underlain by a layer of loose longitudinal muscle fibres. The testes are latero-ventrally distributed but especially greatly accumulated in the rear part of the body (figure 4 C, 6 C), beyond the uteri. The ovaries are dorsal; the uteri are short, filled with small and few mature cells. The male reproductive system is double. Each male copulatory organ consists of a true seminal vesicle, free prostatic vesicle and penis papilla armed with a stylet (figure 5). The swollen vas deferens runs ventrally before entering the elongated seminal vesicle. The seminal vesicle is curved and dorsal to the male prostatic vesicle and stylet; it has a well-developed muscular wall and its lumen is narrow. The rounded prostatic vesicle has a muscular wall and a very high, smooth glandular inner lining. The ciliated ejaculatory duct describes a tortuous trajectory up to reach the penis papilla, having a well-developed muscular layer. The prostatic duct is short and straight, joining the ejaculatory duct beyond the point where the stylet is attached. The stylet is conical and elongated, 330 µm long and slightly curved. The penis sheath is ciliated, short and narrow (figure 6 A). The spacious male atrium is ciliated and directed forwards, opening to a male gonopore located 7.6 mm from the fore end. The second male copulatory organ is similar to the one already described. The female reproductive system is single (figure 5). The oviducts enter the vagina separately from the rear end. The canal is proximally swollen, later narrowing and turning ventrally, to finally enlarge distally. The fore and middle tract of the vagina is immersed in an eosinophilic glandular mass (figure 6 B). There are no cement glands either distally to the vagina or surrounding the elongated female atrium. Without an apparent cement pouch, the vagina and atrium are completely ciliated, underlain by a frail layer of circular muscle fibres. The female atrium opens to a female gonopore ventrally in the midline of body. Taxonomical discussion. Species in genus Thysanozoon are identifiable by their papillated dorsal epidermis, each species showing a definite body shape, a particular distribution of the papillae and a specific colour pattern. The studied specimen of T. brocchii from Mar del Plata matched the detailed descriptions of this species made by Lang (1884) and Stummer-Traunfels (1895). Under the current frame of morphological identification, the crucial characters that discriminate T. brocchii from its relatives are the dorsal surface covered with large bulky conical dark brown papillae, with the margin and cerebral areas free of papillae; its ground colour light brown, delicate translucent in the margins, and the internal anatomy being consistent with the descriptions of the T. brocchii specimens described for Brazil, Curaçao and Patagonia (Marcus 1949, 1952; Marcus & Marcus 1968; Brusa et al. 2009). Marcus (1949) described T. lagidium from the coast of Brazil; later on, after comparing the anatomy with the specimen from Curaçao and Europe, he synonymised T. lagidium with T. brocchii (Marcus & Marcus 1968). These descriptions were accurate enough for Brusa et al. (2009) to identify the specimen from Patagonia as T. brocchii and the specimen from Mar del Plata as well. Thysanozoon brocchii has been described inhabiting Indopacific waters, the Mediterranean, and the Atlantic coast of South America, from the Caribbean to Patagonia. Such a worldwide distribution is curious, especially since water temperature has been considered a limiting factor for the distribution of polyclad species. Prudhoe (1985) proposed that the presence of dorsal papillae in the genera Acanthozoon and Thysanozoon could be related with their flotation capacity as a mean of dispersion, but from personal observation, T. brocchii possess a benthonic life habit, crawling over rocks and into cracks between short swimming periods. Faubel (1984) published a list of pelagic polyclad species collected during different expeditions to South and Central Atlantic Ocean and Sargasso Sea. The unpapillate polyclads collected by these expeditions, were not in accordance to Prudhoe’s (1985) hypothesis. We agree with Brusa et al. (2009) in that the presence of the papillae should be associated with increasing the surface of gas exchange and digestion. The cosmopolitan dispersion of T. brocchii over the South American Atlantic coasts could be associated with the Brazilian ocean current, especially at larval stage. However, because the traditional taxonomy of the Pseudocerotidae is mostly based on external morphological characters, it does not necessarily reflect their phylogenetic relationships. There is still no molecular evidence to discuss if the South American T. brocchii is genetically identical with the morphologically similar specimens collected from the Indopacific waters and Mediterranean coasts.	en	Bulnes, Verónica N., Albano, Mariano J., Obenat, Sandra M., Cazzaniga, Néstor J. (2011): Three Pseudocerotidae species (Platyhelminthes, Polycladida, Cotylea) from the Argentinean coast. Zootaxa 2990: 30-44, DOI: 10.5281/zenodo.202319
8C5F87DF8C60FFF0FF67FEF9822AF873.taxon	diagnosis	Diagnosis. Pseudocerotidae with papillated surface, ground colour greenish yellow covered with rounded black spots, more densely distributed on a mid dorsal band. The papillae are elongated, reddish brown; with a marginal band and cerebral area free of papillae. Conspicuous marginal, colourless tentacles. Two cerebral eye clusters present. The tentacular eyes extend from the fore margin, where they are arranged in a single marginal band, backwards up to the base of the tentacles where they are scattered. Male copulatory apparatus double with conspicuous spermiducal vesicles, a single true seminal vesicle, free prostatic vesicle and a slightly asymmetric stylet. The ejaculatory duct joins the prostatic duct proximally at the base of the penis stylet. Male atrium short, narrow and ciliated. Vagina ciliated, without a cement pouch. Female atrium small and ciliated. Separated gonopores. Ventral sucker in the fore body half.	en	Bulnes, Verónica N., Albano, Mariano J., Obenat, Sandra M., Cazzaniga, Néstor J. (2011): Three Pseudocerotidae species (Platyhelminthes, Polycladida, Cotylea) from the Argentinean coast. Zootaxa 2990: 30-44, DOI: 10.5281/zenodo.202319
8C5F87DF8C60FFF0FF67FEF9822AF873.taxon	materials_examined	Type material. Holotype: 9.0 μm sagittally sectioned specimen, mounted on 180 slides. Collected by M. J. Albano, 21 February 2009 from the Club Náutico de Mar del Plata. On a mussel and ascidians community, 1 – 2 m depth. MACN-In 38207.	en	Bulnes, Verónica N., Albano, Mariano J., Obenat, Sandra M., Cazzaniga, Néstor J. (2011): Three Pseudocerotidae species (Platyhelminthes, Polycladida, Cotylea) from the Argentinean coast. Zootaxa 2990: 30-44, DOI: 10.5281/zenodo.202319
8C5F87DF8C60FFF0FF67FEF9822AF873.taxon	etymology	Etymology. The specific name is dedicated to the memory of Mariano Albano´s mother, Mrs. Mirta R. Elías.	en	Bulnes, Verónica N., Albano, Mariano J., Obenat, Sandra M., Cazzaniga, Néstor J. (2011): Three Pseudocerotidae species (Platyhelminthes, Polycladida, Cotylea) from the Argentinean coast. Zootaxa 2990: 30-44, DOI: 10.5281/zenodo.202319
8C5F87DF8C60FFF0FF67FEF9822AF873.taxon	description	Description. Large, elongated, 36.5 mm long by 20 mm wide alive, 35 mm by 18.4 mm preserved. Marginal tentacles formed by foldings of the fore margin. Dorsal surface covered with elongated reddish brown papillae which are longer and more thickly placed in the centre, declining in length and number to the margins, leaving a marginal band free of papillae. Ground colour is greenish yellow covered with rounded black spots, more densely distributed on a mid dorsal band. With an interrupted reddish brown marginal band. Marginal tentacles without pigmentation, extending between the tentacle bases and reaching the brain dorsally (figures 7 A – 7 B). The dorsal tentacular eye spots are numerous, distributed dorsally in a single row and ventrally scattered. The cerebral eyespots form two separated triangular clusters joining anteriorly. Frontal eyes scattered (figure 7 D). Pharynx ruffled, 5.5 mm long (figure 7 C). The mouth opens at 14 mm from fore margin, behind the pharynx cavity. The main gut opens in the middle of the pharynx cavity roof and runs distally up to short behind the female system. The intestinal ramifications give out extensions into the dorsal papillae (figure 9 C). Dorsal body wall 103 µm high. The ciliated cellular epidermis bears rhabdites and granular pigmentation. The elongated rhabdites are densely packed on the epidermis of the papillae and are readily seen as small red small rods even in living specimens. The granular pigmentation is distributed mostly in the epidermis free of papillae. Beneath the epidermis a layer of circular muscle fibres is present, followed by a longitudinal muscle layer. Ventral body wall 110 µm high, without rhabdites but with granular pigmentation. Beneath the basement membrane, there are a layer of circular muscle fibres and an innermost layer of longitudinal muscle fibres. The ventral epidermis is higher than the ventral one, the ventral circular layer is thinner than the dorsal one, and the ventral longitudinal layer is much higher and dense than the dorsal one. Body parenchyma immersed in a dense net of parenchymatic muscle fibres, giving the body a strong appearance (figure 9 D). The testes are small, widely spaced and ventrally arranged beyond the uteri. The uteri are dorsal to the testes, but ventral to the gut. They are well developed, filled with numerous eggs and located behind the spermiducal vesicles. The male copulatory system is double. Each copulatory organ consists of a true seminal vesicle, free prostatic vesicle and penis papillae armed with a stylet (figure 8). The vas deferens runs ventrally from the rear. After it passes the ventral sucker, the vas deferens distends to form a few voluminous spermiducal vesicles (figure 9 E) before entering the elongated seminal vesicle. The seminal vesicle has a well developed muscular wall and is arranged dorsally to the male prostatic vesicle and stylet. The rounded prostatic vesicle shows a muscular wall and a very high, smooth glandular inner lining. The ciliated ejaculatory duct follows a short trajectory until reaching the penis papillae, its muscular wall being well developed. The prostatic duct is short and straight, joining the ejaculatory duct at the basis of the penis papilla. The stylet is conical and elongated, 760 µm long, slightly asymmetric and sharp. The male atrium is short and narrow, ciliated and directed backwards, opening to a male gonopore located 12 mm from the fore margin (figure 9 B). The second male copulatory organ is similar to the one already described. Both male copulatory organs are symmetrically arranged left and right of the longitudinal body axis. The female reproductive system is single (figure 8). The oviducts enter separately the vagina from the rear, turning ventrally to open distally into a small female atrium and a median gonopore. The canal is about the same diameter along the whole trajectory. The vagina is surrounded by scarce cement glands. There is no cement pouch. The vagina and atrium are completely ciliated. Taxonomical discussion. Thysanozoon mirtae sp. nov. is the only known species having slender, elongated dorsal papillae of reddish brown colour on a greenish yellow body covered with rounded black spots with a reddish brown marginal band; the marginal tentacles and cerebral area devoid of pigment complete an exclusive colour pattern. The presence of slender papillae was described for Thysanozoon skottsbergi Bock, 1913 and T. distinctum Stummer-Traunfels, 1895, while T. minutum Stummer-Traunfels, 1895 has a similar ground body colour. However, the dorsal papillae of T. mirtae sp. nov. differ from the papillae of T. skottsbergi because of the absence of darker pigmentation. The margin of T. distincutum is golden yellow and that of T. minutum is white, sharply different from the reddish brown marginal band of T. mirtae sp. nov. The spermiducal vesicles are thin-walled expansions of the vas deferens serving as storage of sperm (Faubel 1983, p. 21) different from the spermiducal bulbs, which are more muscularized structures, presumably assisting the propulsion of sperm. The apparent spermiducal vesicles and the strongly developed parenchymatic musculature are two main features characterizing the new species T. mirtae. It differs readily from the only species of Thyzanozoon with which it was recorded in sympatry, T. brocchii (Risso 1818), both in colour and anatomy. While T. mirtae is dorsally greenish yellow, covered with translucent, slender reddish brown papillae, with spermiducal vesicles and a well developed mesenchymatic musculature; T. brocchii is dorsally light-brown, covered with, solid, blunt dark brown papillae, without spemiducal vesicles and few mesenchymatic muscle fibres.	en	Bulnes, Verónica N., Albano, Mariano J., Obenat, Sandra M., Cazzaniga, Néstor J. (2011): Three Pseudocerotidae species (Platyhelminthes, Polycladida, Cotylea) from the Argentinean coast. Zootaxa 2990: 30-44, DOI: 10.5281/zenodo.202319
