A new species of<i>Allogenus</i>(Tricladida, Maricola, Uteriporidae) from South Georgia, Sub-Antarctica

South Georgia is a remote sub-Antarctic island, considered a marine biodiversity ‘hotspot’ in the Southern Ocean. During a survey along the north coast of South Georgia several marine planarians were found. One of the specimens was a new species ofAllogenus(Uteriporidae), which is described here asAllogenus sluysisp. nov. The new species has the characteristics of the genus and can be distinguished from the type and only known species,Allogenus kerguelensis, by its smaller size, blackish-brown pigmentation, presence of three retinal cells in each eye cup, position of its testes half-way between the ventral and dorsal body surfaces or at a slightly more ventral position, and by having an ejaculatory duct that opens centrally at the tip of the penis papilla. The presently known geographical distribution ofAllogenus, the heterogeneous marine planarian species composition in South Georgia, and the distribution of these species in this region are in agreement with a previously proposed vicariance hypothesis, albeit that dispersal cannot be ruled out.</jats:p

Polycystidinae Schockaert and Karling 1970

Subfamily POLYCYSTIDINAE Schockaert and Karling, 1970 &lt;p&gt; Genus &lt;i&gt;Austrorhynchus&lt;/i&gt; Karling, 1952&lt;/p&gt; &lt;p&gt; &lt;i&gt;Austrorhynchus wennersgaardi&lt;/i&gt; Volonterio and Ponce de Le&oacute;n, sp. nov.&lt;/p&gt; &lt;p&gt;(Figures 1&ndash;4)&lt;/p&gt; &lt;p&gt; &lt;i&gt;Diagnosis&lt;/i&gt;&lt;/p&gt; &lt;p&gt; &lt;i&gt;Austrorhynchus&lt;/i&gt; species with eyes and white to greyish parenchyma. Type II prostate stylet, double-walled; funnel about 20&ndash;25% of total stylet length, with the proximal rim rolled upon itself to a varying degree; tube of the outer stylet slightly bent, with the inner stylet extending throughout its length; a strongly bent hook arises at the level of the junction between the funnel and the tube; hook and tube of about the same size. Type III stylet with a foot and a shorter style connected by a long bridge, defining a broad window; style expands to a thin comb-bearing plate with large teeth, decreasing in size and thickness towards the base of the flagellum; in general, the third to seventh teeth from the free end of the plate are the larger ones, and their bases are frequently placed at a higher level than those of the rest; foot continues into a sinuous to straight, narrow flagellum, bearing a distal expansion; a row of progressively shorter, fine teeth extends from the base of the flagellum to the proximal part of the expansion. Oviparous.&lt;/p&gt; &lt;p&gt; &lt;i&gt;Description&lt;/i&gt;&lt;/p&gt; &lt;p&gt; &lt;i&gt;General organization.&lt;/i&gt; Preserved specimens are 431&ndash;1044 &micro;m (mean 711.0, SD 191.5) long, white to greyish, rather opaque and bear two eyes (Figure 1). Proboscis about 10&ndash;20% of body length. Pharynx 68&ndash;158 &micro;m (mean 123.7, SD 30.9) in diameter.&lt;/p&gt; &lt;p&gt;Testes paired. Seminal vesicle tapers into an ejaculatory duct opening into proximal end of male genital canal, between bases of type II and III prostate stylets. Prostate vesicle of type II associated with type II stylet. Compact muscle sheet connects wall of prostate vesicle to base of type III stylet.&lt;/p&gt; &lt;p&gt;Paired ovaries and vitellaria. Ovo-vitelloducts of each side join into a common ovovitelloduct. Female bursa connected to a female duct type I, which opens into posterior wall of genital atrium. Common ovo-vitelloduct and insemination ducts open into bursal stalk. Uterus opens into anterior wall of distalmost portion of atrium.&lt;/p&gt; &lt;p&gt; &lt;i&gt;Sclerotized parts of copulatory organ.&lt;/i&gt; The double-walled type II prostate stylet (Figure 2 (a,b)) is 40&ndash;49 &micro;m (mean 44.5, SD 2.2) long and consists of a funnel, a distal tube and a hook. The funnel is 8&ndash;14 &micro;m (mean 10.4, SD 1.6) long (about 20&ndash;25% of the total stylet length) and 22&ndash;33 &micro;m (mean 28.9, SD 2.8) wide proximally; its proximal rim is broad and rolled upon itself to a varying degree. Tube of outer stylet slightly bent, 27&ndash;34 &micro;m (mean 31.1, SD 2.0) long, 11&ndash;17 &micro;m (mean 13.8, SD 1.6) wide proximally and 5&ndash;8 &micro;m (mean 6.4, SD 1.1) wide distally; inner stylet extends throughout its length. In a few specimens, distal portion of tube of outer stylet is dilated (Figure 2 (b)). A large, 28&ndash;34 &micro;m (mean 31.0, SD 2.1) long, strongly bent hook arises at the level of the junction between the funnel and the tube.&lt;/p&gt; &lt;p&gt;Type III prostate stylet (Figure 2 (c,d)) has a foot and style connected by a long bridge, defining a broad window. Style expands to a thin comb-bearing plate carrying 22&ndash;27 &micro;m (mean 24, SD 1.9) large teeth. In general, third to seventh teeth from free end of plate are the larger ones, measuring 10&ndash;15 &micro;m (mean 12.1, SD 1.6) in length; their bases are frequently placed at a higher level than those of the rest (Figure 2 (d)). Remaining teeth on comb decrease in size and thickness towards base of flagellum. Flagellum, 29&ndash;37 &micro;m (mean 32, SD 2.6) in length, is sinuous to straight and has a distal expansion; a row of progressively shorter, fine teeth extends up to proximal part of latter. Distance from proximal end of foot to tip of flagellum is 59&ndash;77 &micro;m (mean 71.5, SD 4.7).&lt;/p&gt; &lt;p&gt; &lt;i&gt;Histology.&lt;/i&gt; At the histological level, the overall characteristics of the new species are in agreement with the previous histological descriptions of &lt;i&gt;Austrorhynchus&lt;/i&gt; (Karling 1952; Brunet 1965); the relevant differences are described below.&lt;/p&gt; &lt;p&gt; The genital canal can be divided into three sections based on the histology of its wall (Figure 3 (a)): (i) the proximal portion of the male genital canal, with an epithelium bearing pseudo-cilia surrounded by an internal layer of thin circular muscle fibres and two external layers composed of thick, oblique fibres; (ii) the distal portion of the male genital canal, where the internal oblique fibres adopt a longitudinal direction and the external ones are replaced by a sphincter; (iii) the &lt;i&gt;atrium inferius sensu&lt;/i&gt; Karling 1952, with an epithelium bearing long pseudo-cilia and a mono-layer of thin circular muscle fibres surrounded by scarce longitudinal fibres. Most of the longitudinal fibres present in the distal portion of the male genital canal leave the wall of the canal immediately below the sphincter and attach to the ventral body wall close to the gonopore.&lt;/p&gt; &lt;p&gt;In a few specimens (for example, NHMUK 2017.11.3.11), the anterior wall of the genital canal is dilated at the level of the sphincter, forming a pouch (Figure 3 (a,b), indicated with an arrowhead). Sperm cells seen in the male genital canal were always located in the vicinity or at the level of the sphincter, either in the main cavity of the canal or inside the pouch.&lt;/p&gt; &lt;p&gt;Gland cells open into the dorsal wall of the bursal stalk, just posteriorly to the opening of the common ovo-vitelloduct. In a few specimens, the ventral wall of the bursal stalk presents an expansion filled with sperm cells (Figure 3 (a,c), indicated with an asterisk).&lt;/p&gt; &lt;p&gt; &lt;i&gt;Material examined&lt;/i&gt;&lt;/p&gt; &lt;p&gt; &lt;i&gt;Holotype.&lt;/i&gt; One whole mount of a specimen from Balvino Point, King George Island, South Shetland Islands (62.188889&ordm;S, 58.903889&ordm;W), Antarctica, collected by Odile Volonterio and Rodrigo Ponce de Le&oacute;n on 22 January 2009, deposited in the Natural History Museum (NHM), London (accession number: NHMUK 2017.11.3.1).&lt;/p&gt; &lt;p&gt; &lt;i&gt;Paratypes.&lt;/i&gt; Eight slides with whole mounts of specimens from Balvino Point, Maxwell Bay, King George Island, South Shetland Islands (62.188889&ordm;S, 58.903889&ordm;W), Antarctica, collected by Odile Volonterio and Rodrigo Ponce de Le&oacute;n on 19 December 2006 (two slides), 5 January 2008 (one slide), 6 January 2009 (one slide), 24 January 2009 (two slides) and 6 February 2009 (two slides with gravid specimens); one slide with a whole mount of a specimen from Pata de Perro Point, Maxwell Bay, King George Island, South Shetland Islands (62.185278&deg;S, 58.878889&deg;W), Antarctica, collected by Odile Volonterio and Rodrigo Ponce de Le&oacute;n on 29 January 2010. Deposited in the Natural History Museum (NHM), London (accession numbers: NHMUK 2017.11.3.2&ndash;9 and 2017.11.3.10 respectively).&lt;/p&gt; &lt;p&gt; &lt;i&gt;Additional material.&lt;/i&gt; Two slides with sagittal sections of two specimens from Balvino Point, King George Island, South Shetland Islands (62.188889&ordm;S, 58.903889&ordm;W), Antarctica, collected by Odile Volonterio and Rodrigo Ponce de Le&oacute;n on 22 January 2009, deposited in the Natural History Museum (NHM), London (accession number: NHMUK 2017.11.3.11&ndash;12).&lt;/p&gt; &lt;p&gt; &lt;i&gt;Biology&lt;/i&gt;&lt;/p&gt; &lt;p&gt; The species is oviparous. In February 2009 two gravid specimens, each carrying a single egg, were found; eggs are oval, 282&ndash;299 &micro;m (mean 290.5, SD 12.0, &lt;i&gt;n&lt;/i&gt; = 2) long, 231&ndash;243 &micro;m (mean 237.0, SD 8.5, &lt;i&gt;n&lt;/i&gt; = 2) wide and present a short adhesive peduncle (Figure 4).&lt;/p&gt; &lt;p&gt; &lt;i&gt;Distribution&lt;/i&gt;&lt;/p&gt; &lt;p&gt;King George Island, South Shetland Islands, Maritime Antarctic.&lt;/p&gt; &lt;p&gt; &lt;i&gt;Etymology&lt;/i&gt;&lt;/p&gt; &lt;p&gt; Specific name in honour of the Norwegian sailor Ole Wennersgaard, a crew member of the Swedish Antarctic Expedition who died during the extreme Antarctic winter of 1903, when part of the expedition was forced to remain in Poulet Island until rescued by the vessel &lt;i&gt;Uruguay&lt;/i&gt; (Ekelof 1904).&lt;/p&gt;Published as part of &lt;i&gt;Volonterio, Odile &amp; Ponce de León, Rodrigo, 2018, A new species of Austrorhynchus (Platyhelminthes: Kalyptorhynchia) from King George Island (Maritime Antarctic), pp. 739-750 in Journal of Natural History (J. Nat. Hist.) (J. Nat. Hist.) 52 (11 - 12)&lt;/i&gt; on pages 741-746, DOI: 10.1080/00222933.2018.1444212, &lt;a href="http://zenodo.org/record/5174376"&gt;http://zenodo.org/record/5174376&lt;/a&gt

Temnocephala Blanchard 1849

&lt;i&gt;Temnocephala&lt;/i&gt; Blanchard, 1849 &lt;p&gt;Temnocephalidae of small to medium size. Body contour approximately elliptical, with a marked dorsal convexity and a slight ventral concavity. Five anterior, relatively long tentacles, quite extensible, the median one slightly longer than the lateral ones. Subterminal, ventral, pedunculated sucker present. Epidermis with four syncytial plates (one body syncytium, one adhesive disc syncytium and two excretory syncytia). Two dorsal, prepharyngeal eyes, always pigmented. Mouth ventral, subterminal. Pharynx with two sphincters, generally a small anterior one and a large posterior one, or, more rarely, subequal in diameter. Two excretory vesicles; dorsal nephridiopores, within the excretory syncytia. Hermaphroditic. Generally with four testes, more rarely two. An ovary. Pedunculated eggs.&lt;/p&gt;Published as part of &lt;i&gt;León, Rodrigo Ponce De &amp; Volonterio, Odile, 2018, A new species of Temnocephala (Platyhelminthes) with an unusual pharynx, including an amendment of the diagnosis of the genus, pp. 323-336 in Zootaxa 4378 (3)&lt;/i&gt; on page 331, DOI: 10.11646/zootaxa.4378.3.2, &lt;a href="http://zenodo.org/record/1169955"&gt;http://zenodo.org/record/1169955&lt;/a&gt

First discovery – and a new species – of Coelogynopora (Platyhelminthes, Proseriata) in the Southern Hemisphere

Coelogynoporidae (Platyhelminthes) includes comparatively large and slender Proseriata, usually occurring in shallow benthic environments. Coelogynopora Steinböck, 1924 is the most frequently reported genus and the one with the highest species diversity. Notwithstanding that, the genus has never been reported from the Southern Hemisphere. A recent analysis of sediment from the Magellan Strait shores (Chile) resulted in the discovery of a new species of Coelogynopora, the first representative of the genus to be found in austral waters. The new species is defined by the following combination of characters: sclerotised copulatory system consisting of a slender, ventrally curved stylet with a broad base and three pairs of symmetrically arranged spines, the proximal ends of which are fused laterally to the base of the stylet; distal ends of the three pairs of spines hooked, with apophyses at progressively longer distances from the tip; accessory spines and solar organ absent. Based on the morphological characters, the new species appears to be more related to species from the Pacific Ocean than to those from the Atlantic Ocean. The present work suggests a vast biogeographic disjunction in the genus Coelogynopora, which may be described as a bipolar or amphitropical pattern of distribution

Coelogynopora kenichii Volonterio & León 2021, sp. nov.

Coelogynopora kenichii sp. nov. urn:lsid:zoobank.org:act: FC85AFB9-55C1-47C4-8A5F-AEA9FD3D3D22 Figs 1–6 Diagnosis Coelogynopora kenichii sp. nov. is defined by the following combination of characters: sclerotised copulatory system consisting of a slender, ventrally curved stylet with a broad base, and three pairs of symmetrically arranged spines, the proximal ends of which are fused laterally to the base of the stylet. Distal ends of the three pairs of spines hooked, with apophyses at progressively longer distances from the tip. Accessory spines and solar organ absent. Etymology We dedicate this species to Prof. Dr Ken-Ichi Tajika for his highly relevant contributions to the systematics of Coelogynoporidae and other Proseriata. Type material Sixteen whole mounts and two series of sagittal and transversal sections. Material examined Holotype CHILE • Whole mount, stained with carmine and fast green, mounted in Canada balsam; coast of the Magellan Strait, Magellan Province; 53.016667° S, 70.816667° W; 6 Jan. 2005; R. Ponce de León leg.; RMNH.VER.19980.a. Paratypes CHILE • 16 whole mounts, 2 series; same collection data as for holotype. RMNH.VER.19980.b to RMNH.VER.19980.k (10 whole mounts, stained with carmine and fast green, mounted in Canada balsam), RMNH.VER.19980.l (a series of sagittal sections stained with hematoxylin-eosin), RMNH. VER.19980.m (a series of transversal sections in four slides, stained with hematoxylin-eosin), RMNH.VER.19980.n (two whole mounts in one slide, cleared and mounted in lactophenol), RMNH. VER.19980.o (a whole mount, cleared and mounted in lactophenol) and RMNH.VER.19980.p (three whole mounts in one slide, cleared and mounted in lactophenol). Description BODY SIZE. Live, adult animals filiform, 5.24–8.82 mm long (6.47, 1.610, 4). Fixed specimens 2.57– 5.72 mm long (3.92, 0.981, 11) and 125–286 µm (198, 50.3, 10) wide at the level of the ovaries (Fig. 1A). SENSORY ORGANS AND GLANDS. Anterior end of the body provided with short sensory bristles and a few long tactile hairs (Fig. 1B). Two types of gland cells open through the anterior epidermis: one that stains green with fast green, and another one, smaller, that does not. Encapsulated brain, anteriorly trilobate, at about 4.4% from the anterior end of the body (Fig. 1B); 54–82 µm (64, 8.8, 9) long, and 40–67 µm (50, 9.4, 9) maximum width. Statocyst with two pairs of statoliths at about 3.2% from the anterior end (Fig. 1B), 11–16 µm (14, 1.7, 7) in diameter. At least three types of parenchymal gland cells, with different affinities for the stains used, open through the epidermis of the general body surface. An aggregation of gland cells is also present in the posterior end of the body. Paracnids absent. DIGESTIVE SYSTEM. Intestine with an anterior, hollow pre-cerebral diverticulum–“ Kopfdarm ” or “ chorda intestinalis ” sensu Ax (1957) and Ax & Ax (1969) – that arises at the level of the posterior part of the brain, continues anteriorly as a narrow tube, dorsally to the brain and the statocyst, and widens anteriorly to the latter, extending almost to the anterior end of the animal (Fig. 1B). The diverticulum is lined with a thin wall and has a wide lumen except in the region directly above the brain and statocyst; intestinal contents were seen in transversal sections throughout its length. The pharynx, directed ventrally, is at about 75% from the anterior end and has numerous anterior and posterior associated glands (Fig. 1A). MALE REPRODUCTIVE SYSTEM. An irregular median row of 41–85 (55, 13.4, 10) testicular follicles extends from 26% to 66% from the anterior end (Fig. 1A). Each follicle is 42–63 µm (50, 5.3, 24) long, 15–33 µm (21, 5.2, 24) wide. Two long vasa deferentia extend posteriorly almost to the end of the body, turn 180 degrees, and run anteriorly following a sinuous course, opening into the proximal end of each of the two seminal vesicles (Fig. 2). The seminal vesicles open into a common ejaculatory duct that runs dorsally and enters the prostatic vesicle (Figs 2–3). Several prostatic glands surround the ejaculatory duct and the proximal part of the prostatic vesicle, opening into the latter. Oblique muscle fibres surround the prostatic vesicle, giving a continuous layer that is thicker ventrally. The sclerotised copulatory system lies anterior to the gonopore, is directed downwards and forwards, and opens into the anterior end of the genital atrium (Fig. 3). It consists of a stylet and 3 pairs of symmetrically arranged spines (Fig. 4). The stylet is slender, ventrally curved, and is provided with a broad base (Fig. 4A); it is 77–97 µm long (90, 6.4, 10) and 16–24 µm (20, 2.7, 10) in basal width. The three pairs of spines are 75–90 µm (84, 4.6, 10), 78–93 µm (88, 5.0, 10) and 81–97 µm (91, 5.1, 10) in length; the smallest are the farthest from the stylet. The proximal ends of all three pairs of spines are fused laterally to the base of the stylet (Fig. 4A–B); their distal ends are hooked, and their apophyses are placed at progressively longer distances from the tip (Fig. 4C). FEMALE REPRODUCTIVE SYSTEM. The vitellaria consist of many follicles in two rows that are lateral to the intestinal sac; they extend from well behind the brain to about the level of the anterior part of the genital atrium (Fig. 1A). Two elliptical ovaries are approximately halfway between the level of the more posterior testes and the anterior end of the pharynx (Fig. 1A); they are 36–75 µm (54, 12.1, 11) long and 24–37 µm (31, 4.0, 11) wide. Two ciliated ovovitelline ducts run posteriorly and open laterally into the ciliated, caudal end of the genital atrium, just behind the gonopore. A winding, narrow genital canal leads from the posterior atrial wall to the intestinal wall; it opens into the intestinal lumen, giving a genito-intestinal connection (Fig. 3). The canal is thick-walled and lined with ciliated epithelium. The distalmost portions of the ovovitelline ducts, the genital canal and the caudal atrial wall are surrounded by glands. The genital pore is at about 80% from the anterior end, at the level of the posterior end of the prostatic vesicle (Figs 1A, 3); it does not have an obvious sphincter. FIBROUS ORGAN. An unknown structure was observed in every specimen studied, behind the reproductive complex and at the level of a posterior constriction of the body. In whole mounts, it appears as a welldefined, clear area (Fig. 5A); in histological sections, it is evident as a dorsal, fibrous mass between the body wall and the intestine that extends anteriorly for a short distance (Fig. 5B). It does not stain with carmine (compare the seminal vesicles with the organ in Fig. 5A), and only a few filaments are stained with hematoxylin (Fig. 5B), so the presence of sperm cells is ruled out. We cannot entirely exclude the possibility of the presence of muscle cells because of a weak affinity with the fast green stain and because the few fibres that stain with hematoxylin have a strong affinity to the dye, comparable to that of the adjacent circular muscle fibres. However, this seems unlikely because the fibres run in random directions. Interestingly, at this level the longitudinal musculature of the body wall is interrupted, and only a few circular muscle fibres are present. No parenchymal gland cells were seen associated with this structure, either. This fibrous mass was present in all the specimens, and its position, general organisation, and staining properties were constant; it is, therefore, unlikely to be an artefact. Given the absence of an analogous structure in the relevant bibliography, and for lack of a better term, we call it the 'fibrous organ'. Taxonomic remarks The following combination of morphological characters places the new species unequivocally in the genus Coelogynopora sensu Karling (1966) and Faubel & Rohde (1998): epidermis entirely ciliated, with intracellular nuclei; sclerotised copulatory system with stylet and spines (note that hard parts are variable among representatives of the genus, to the point that they may be absent); paired seminal vesicles located posteriorly to the gonopore; paired ovaries situated anteriorly to the pharynx, with two ovovitelline ducts that open separately into the posterior part of the genital atrium. While a bursa could not be discerned, a conspicuous female genital canal opens into the intestine through a genito-intestinal connection. There are currently 39 known species of Coelogynopora (Armonies 2018; Jouk et al. 2019), but, besides C. kenichii sp. nov., only three other species have all the spines fused proximally with the base of the penial stylet, namely Coelogynopora alata Tajika, 1981, Coelogynopora brachystyla Karling, 1966 and Coelogynopora coniuncta Tajika, 1978. Coelogynopora kenichii sp. nov. differs from all of them by having a different number of spines and by the shape of the penial stylet. Tajika (1981) reported 36 spines in C. alata; in addition, the penial stylet has a more conical shape. Coelogynopora brachystyla has a single pair of spines; in addition, the penial stylet has a truncated end and bears a longitudinal slit that has been described as a “channel” (Karling 1966). The closest species to C. kenichii sp. nov. is C. coniuncta. However, the penial stylet in the latter is longer than in C. kenichii sp. nov., and its base is much broader (the proportion of basal length to total length is 66% in C. coniuncta and 29% in C. kenichii sp. nov.); in addition, in C. coniuncta there are only four spines (Tajika 1978, 1981). Besides the differences in the sclerotised copulatory system, in C. coniuncta the vasa deferentia enter the seminal vesicles through their anterior, ventral sides and not posteriorly as in C. kenichii sp. nov.; furthermore, in C. coniuncta the seminal vesicles extend posteriorly and, in most specimens, they were found to be fused at the level of the posterior end of the animal (Tajika 1978).Published as part of Volonterio, Odile & León, Rodrigo Ponce De, 2021, First discovery and a new species of Coelogynopora (Platyhelminthes, Proseriata) in the Southern Hemisphere, pp. 185-196 in European Journal of Taxonomy 775 on pages 187-191, DOI: 10.5852/ejt.2021.775.1557, http://zenodo.org/record/560469

A new species of Temnocephala (Platyhelminthes) with an unusual pharynx, including an amendment of the diagnosis of the genus

León, Rodrigo Ponce De, Volonterio, Odile (2018): A new species of Temnocephala (Platyhelminthes) with an unusual pharynx, including an amendment of the diagnosis of the genus. Zootaxa 4378 (3): 323-336, DOI: https://doi.org/10.11646/zootaxa.4378.3.

Temnocephala gargantua León & Volonterio 2018, sp. nov.

Temnocephala gargantua sp. nov. Ponce de León & Volonterio (Figs. 1–7) Diagnosis. Temnocephala gargantua sp. nov. is characterized by having a slightly curved penial stylet (225 µm in length) with a symmetrical introvert (27 long by 18 µm in diameter) that has at least 44 spine-like projections, each bearing 7 rows of internal spines; a seminal vesicle that opens sub-polarly into the contractile vesicle; a muscular vagina with a strong asymmetrical sphincter; preequatorial nephridiopores close to the internal borders of the elongate-oval excretory syncytia; a large pharynx with anterior and posterior sphincters of about the same diameter and a narrow pharyngeal lumen, nearly uniform in width. Description. Temnocephalan of large size; elliptic body, with maximum width at the level of the space between anterior and posterior testes (Fig. 1). Body without tentacles 2166.7 to 4074.1 (2925.9; 612.76; 10) long by 1148.1–1833.3 (1514.8; 259.81; 10) wide. Sucker subterminal, 518.5–907.4 (670.4; 117.70; 10) in diameter. Peduncle generally with an oblique, ventro-caudal orientation. Ratio body length without tentacles to sucker length 1:0.18–0.35 (mean 1:0.24). Sucker glands anterior to sucker peduncle, scattered between, and posterior to, posterior testes (Fig. 1). Epidermis with elongate-oval excretory syncytia, extending from the base of the outermost tentacles to the level of the anterior portion of the intestine (Fig. 2). Excretory vesicles lateral to pharynx; nephridiopores dorsal, close to internal border of excretory syncytia and preequatorial respect to them (Figs. 1, 2). Haswell glands conspicuous, anterior to pharynx (Fig. 1). Abundant tentacular glands, situated laterally to the intestine (Fig. 1). Large, elliptical pharynx, of about the same size as the intestine (Fig. 3), 444.4–759.3 (606.3; 84.31; 10) long by 481.5–851.9 (690.7; 120.68; 10) wide. Pharynx wall 192.9–202.1 (197.5; 2) maximum width. Anterior sphincter of about the same diameter as, but more flattened than, the posterior one (Figs. 4; 5A,B); section of the muscle bundle 107.1 measured radially and 44.3 measured anteroposteriorly. Section of the muscle bundle of the posterior sphincter 115.7 measured radially and 101.4 measured anteroposteriorly. The external circular musculature is a monolayer of fibers with a height of 0.7 at the level of the anterior sphincter. Posteriorly to this level the layer abruptly acquires a height of 5 and at the level of the posterior sphincter it decreases gradually to 1.8. This monolayer seems to be confluent with a small bundle of circular muscle fibers that is situated at the base of the pharynx, seemingly surrounding the entrance to the esophagus (Fig. 5B). External longitudinal muscle layer roughly homogeneous in height (14.3). The internal longitudinal fibers arise and end in the pharyngeal sphincters, giving a layer of about 28.6 in height. The internal layer of circular muscles extends between both sphincters without overlapping with them; it is composed by a monolayer of high fibers (Fig. 5C) whose sections measured radially are 9.3 in the anterior region, 32.5 in the median region and 6.4 in the posterior region of the pharynx. Besides the circular and longitudinal muscle fibers, abundant radial fibers were seen (Fig. 4). Among the radial muscle fibers between the sphincters, at least 2 different types of cells were observed, the first type with clear cytoplasm and abundant extensions toward the surrounding tissues, and the second type with abundant dark granules in the more dense cytoplasm, and fewer extensions (Figs. 4, 5D,E). The pharyngeal epithelium is a wide layer of fibrous aspect, deeply staining dark-blue with Heidenhain’s haematoxylin (Figs. 4, 5C). No nuclei were seen at this level; these are placed outside of the pharynx as cytons. The height of the epithelial layer is 2.4 anteriorly, 6.4–11.5 (8.3; 2) medially and 3.1 posteriorly. Pharyngeal lumen narrow and nearly uniform in width (Fig. 4). Short esophagus surrounded by a layer of circular muscle fibers resembling a sphincter (Fig. 5F). Intestine longer than wide, with a slight central constriction and conspicuous septa. The posterior end of the intestinal sac reaches the level of the posterior testes; ratio body length without tentacles to distance between the posterior end of the intestine and base of tentacles 1:0.58–0.72 (mean 1:0.65). Ovoid ovary, 91.0–145.5 (119.5; 17.96; 9) long by 78.2–134.5 (103.6; 17.70; 9) wide. The short oviduct opens into the ootype just opposite the entrance of the seminal receptacle (Fig. 6A,B). Abundant glandular cells surround the ootype, with ducts that open into it. Resorbiens vesicle in the space left by the posterior constriction of the intestine and generally posterior to the level of the gonopore (Figs. 1, 3), ovoid in shape, 149.1–236.4 (186.2; 35.76; 5) long by 118.2–207.3 (162.6; 36.07; 5) wide. The posterior part of the resorbiens vesicle is more flattened and has a thicker wall than the anterior one; this thick-walled portion gives rise to the short duct that leads to the seminal receptacle, which is surrounded by a sphincter (Fig. 6A, B). The seminal receptacle is an expansion of the wall of the duct that connects the ootype with the resorbiens vesicle (Fig. 6A,B). Vagina 109.9–147.2 (128.6; 26.38; 2) long by 81.1–108.1 (94.6; 19.09; 2) maximum width; distal portion with an asymmetrical sphincter, 68.5– 108.1 (87.1; 19.91; 3) in diameter (Fig. 6C). Female portion of atrium surrounded by several gland cells with ducts that open into its lumen (Fig. 6B). Vitelline glands branched (Fig. 1B), surrounding intestine completely (Fig. 3). Eggs not observed. Testes ovoid; two lateral to the posterior portion of the intestine and two larger, posterior to the same organ and more central (Fig. 1). Anterior testes 166.7–296.3 (224.1; 39.47; 10) long by 74.1–185.2 (138.9; 34.10; 10) wide. Posterior testes 203.7–351.9 (290.7; 50.18; 10) long by 129.6–240.7 (198.1; 32.71; 10) wide. The thick vasa efferentia enter the seminal vesicle adjacent to each other (Fig. 6A). The seminal vesicle is pyriform, 191.0–298.2 (257.9; 33.59; 9) long by 95.0–173.0 (128.5; 29.22; 8) maximum width; wall 5.4–11.7 (7.8; 1.88; 11) thick; it opens into the contractile vesicle in a sub-polar position. Contractile vesicle 109.1–163.6 (143.7; 17.39; 10) long by 64.0–109.1 (92.5; 13.38; 10) maximum width; wall 2.7–7.2 (5.6; 1.75; 11) thick. No prostatic glands were seen externally to the contractile vesicle. Penial stylet slightly curved (Fig. 7A); 200.0–258.2 (225.4; 18.59; 9) long by 45.5–63.6 (52.3; 6.64; 9) proximal width. Symmetrical introvert 27.3 long by 14.5–22.0 (17.8; 2.42; 9) maximum width, bearing at least 44 spine-like projections, each bearing 7 rows of internal spines (Fig. 7B). Gonopore at the level of the space between the anterior and posterior testes, surrounded by glands; ratio body length without tentacles to distance between gonopore and base of tentacles 1:0.54–0.65 (mean 1:0.57).Published as part of León, Rodrigo Ponce De & Volonterio, Odile, 2018, A new species of Temnocephala (Platyhelminthes) with an unusual pharynx, including an amendment of the diagnosis of the genus, pp. 323-336 in Zootaxa 4378 (3) on pages 324-327, DOI: 10.11646/zootaxa.4378.3.2, http://zenodo.org/record/116995

First discovery – and a new species – of Coelogynopora (Platyhelminthes, Proseriata) in the Southern Hemisphere

Coelogynoporidae (Platyhelminthes) includes comparatively large and slender Proseriata, usually occurring in shallow benthic environments. Coelogynopora Steinböck, 1924 is the most frequently reported genus and the one with the highest species diversity. Notwithstanding that, the genus has never been reported from the Southern Hemisphere. A recent analysis of sediment from the Magellan Strait shores (Chile) resulted in the discovery of a new species of Coelogynopora, the first representative of the genus to be found in austral waters. The new species is defined by the following combination of characters: sclerotised copulatory system consisting of a slender, ventrally curved stylet with a broad base and three pairs of symmetrically arranged spines, the proximal ends of which are fused laterally to the base of the stylet; distal ends of the three pairs of spines hooked, with apophyses at progressively longer distances from the tip; accessory spines and solar organ absent. Based on the morphological characters, the new species appears to be more related to species from the Pacific Ocean than to those from the Atlantic Ocean. The present work suggests a vast biogeographic disjunction in the genus Coelogynopora, which may be described as a bipolar or amphitropical pattern of distribution.</jats:p