Submarine groundwater discharge into a semi-enclosed coastal bay of the southern Baltic Sea: A multi-method approach

The present study aims to understand the impact of submarine groundwater discharge (SGD) on a coastal area with different lithology and degrees of SGD. Sampling campaigns took place in Puck Bay and the Gulf of Gdańsk, southern Baltic Sea encompassing years between 2009 and 2021. The methodological approach combined geophysical characterization of the surface sediments with detailed spatial and temporal (isotope) biogeochemical investigations of pore and surface waters, and was supported by nearshore groundwater and river surveys. Acoustic investigations identified areas of disturbance that may indicate zones of preferential SGD release. The composition of porewater and the differences in the bay's surface waters disclosed SGD as common phenomenon in the study area. Regional SGD was estimated through a radium mass balance. Local estimation of SGD, based on porewater profiles, revealed highest SGD fluxes at the sandy shoreline, but relatively low elemental fluxes. Though SGD was low at the muddy sites corresponding elemental fluxes of nutrients and dissolved carbon exceeded those determined at the sandy sites due to intense diagenesis in the top sediments. SGD appears to be sourced from different freshwater endmembers; however, diagenesis in surface sediments substantially modified the composition of the mixed solutions that are finally discharged to coastal waters. Overall, this study provides a better understanding of the SGD dynamics in the region by a multi-approach and emphasizes the need to understand the processes occurring at the sediment-water interface when estimating SGD

A huge biocatalytic filter in the centre of Barents Sea shelf?

A primary production model for the Barents Sea shows a hot spot of organic carbon settlement to the sea bed over 100 km long, a shallow pile of highly permeable sediments (mainly large Balanus, Mya and Pecten shell fragments over 1 cm in size) of glacial origin. Hydrodynamic flow models suggest an intensive, deep flow of near-bottom waters into the sediment. Depending on wave height, water in shallow (30 m depth) places may percolate more than 5 m into the sediment. During 10 days of stormy weather as much as 4 to 8 kg wet weight pelagic biomass can be processed per square metre through this extremely permeable sediment. Analogous processes known in coastal waters lead to intense biocatalytic phenomena and metabolism of organic carbon within the seabed, estimated here as more intense than surface consumption. Spitsbergenbanken may be acting as a huge sink for organic carbon and an important source of nutrients in one of the most productive areas of the North Atlantic

Acute aquatic toxicity of arsenic-based chemical warfare agents to Daphnia magna

Sea dumping of chemical warfare (CW) took place worldwide during the 20th century. Submerged CW included metal bombs and casings that have been exposed for 50-100 years of corrosion and are now known to be leaking. Therefore, the arsenic-based chemical warfare agents (CWAs), pose a potential threat to the marine ecosystems. The aim of this research was to support a need for real-data measurements for accurate risk assessments and categorization of threats originating from submerged CWAs. This has been achieved by providing a broad insight into arsenic-based CWAs acute toxicity in aquatic ecosystems. Standard tests were performed to provide a solid foundation for acute aquatic toxicity threshold estimations of CWA: Lewisite, Adamsite, Clark I, phenyldichloroarsine (PDCA), CWA-related compounds: TPA, arsenic trichloride and four arsenic-based CWA degradation products. Despite their low solubility, during the 48 h exposure, all CWA caused highly negative effects on Daphnia magna. PDCA was very toxic with 48 h D. magna LC50 at 0.36 mu g x L-1- and Lewisite with EC50 at 3.2 mu g x L-1 . Concentrations at which no immobilization effects were observed were slightly above the analytical Limits of Detection (LOD) and Quantification (LOQ). More water-soluble CWA degradation products showed no effects at concentrations up to 100 mg x L-1.Peer reviewe

Baltic Sea Gastrotricha—one new species and one new record of Chaetonotida from Poland

Kolicka, Małgorzata, Jankowska, Emilia, Kotwicki, Lech (2015): Baltic Sea Gastrotricha—one new species and one new record of Chaetonotida from Poland. Zootaxa 4027 (4): 487-508, DOI: 10.11646/zootaxa.4027.4.

Heterolepidoderma Remane 1927

Genus: <i>Heterolepidoderma</i> Remane, 1927 <p> <i>Typus generis</i>: <i>Heterolepidoderma ocellatum</i> (Mečnikow, 1865)</p> <p> <i>Terra typica:</i> Russia</p> <p> <i>Heterolepidoderma</i> Remane, 1927 is considered a polyphyletic genus (Kieneke <i>et al.</i> 2008, Kånneby <i>et al.</i> 2012, 2013) that encompasses 21 nominal freshwater species and 13 nominal marine species (Todaro 2015; Kieneke <i>et</i> Schmidt-Rhaesa 2015). It is present in benthic, interstitial and peryphytic habitats (Kisielewski 1997).</p>Published as part of <i>Kolicka, Małgorzata, Jankowska, Emilia & Kotwicki, Lech, 2015, Baltic Sea Gastrotricha — one new species and one new record of Chaetonotida from Poland, pp. 487-508 in Zootaxa 4027 (4)</i> on page 489, DOI: 10.11646/zootaxa.4027.4.2, <a href="http://zenodo.org/record/232762">http://zenodo.org/record/232762</a&gt

Heterolepidoderma sinus Kolicka, Jankowska & Kotwicki, 2015, spec. nov.

<i>Heterolepidoderma sinus</i> spec. nov. <p>(Figs. 1–6; Table 1 –2)</p> <p>This new species has been described by the first author (M. Kolicka).</p> <p> <b>Locality. Southern Baltic Sea,</b> outer Puck Bay, Jastarnia (N54° 41.4 E 18°40.9)</p> <p> <b>Material.</b> Twelve specimens (11 adult and 1 juvenile), including 7 photographed. The micro-photographs are available in the Natural History Collections at Adam Mickiewicz University in Poznań under access numbers NHC-GHS- 10-1-10 /h (holotype) and NHC-GHS- 10-11-15 /p (paratypes) and in the author's collection.</p> <p> <b>Etymology.</b> From Latin <i>sinus,</i> ‘ <i>bay,’</i> referring to the place where the species was found.</p> <p> <b>Diagnosis.</b> Body length from 102.0 to 128.5 Μm. Stocky body. Head short, five-lobed. Cephalion wide; epipleuria small, weakly marked in the head outline; hypopleuria large, convex and clearly marked. No ocellar granules present. Hypostomium large and rectangular. Pharynx narrow, with anterior and posterior dilatations. The anterior dilatation is stronger than the posterior one. Inside the anterior pharynx dilatation a strong cuticular reinforcement, composed of two thick rods connected at a right angle and a thinner transverse bar. Scales form 35– 39 individual longitudinal rows, 23–27 scales in each. Scales located close one to another. Their edges juxtaposed but do not overlap. Scales have a strong, long keel that continues into a short, vestigial spine. Two types of lamellae are present: triangular small lamellae that emerge from lateral scales and large, long lamellae that emerge from ventral scales located directly at the ciliary bands. Ventral interciliary field is covered from the beginning of the anterior pharynx dilatation with narrow, oval scales with long clear keel and a thin, straight spine. Three pairs of terminal scales of the ventral interciliary field are oval and without a posterior notch and have long keels and straight spines.</p> <p> <b>Description.</b> <i>Heterolepidoderma sinus</i> <b>spec. nov.</b> is a species with a stocky body, clearly marked neck constriction and a narrow furca base. The head is short, blunt and five-lobed. The cephalion (U1–U3) is wide and short (Table 1), and adheres to the head along its entire length. Epipleuria (U4) are very small and weakly marked in the head outline. Hypopleuria (U4–U10) are large (over five times larger than the epipleuria), strongly convex and clearly marked in the body outline. Epipleuria are located on dorsolateral and lateral body sides. A greater part of hypopleuria are located dorsally, dorsolaterally and laterally, with only a small part of them located ventrolaterally and ventrally. The hypostomium (U6–U9) is large, rectangle-shaped with rounded edges and has no reinforcements. Two pairs of cephalic ciliary tufts, four cilia each, are present. The anterior tufts emerge dorsally between the cephalion and epipleuria on U3. The first cilium in both anterior tufts is the shortest. Two subsequent cilia are longer and similar in length. The fourth cilium is the longest. Posterior tufts emerge ventrolaterally from the notch between the epipleuria and the hypopleuria on U4/5. The first cilium in both posterior tufts is the shortest. The second cilium is much longer than the first one. The third cilium in both tufts is shorter than the second one. The fourth cilium is shorter than the third one but longer than the first one (see Table 1). Ocellar granules are not present. The mouth ring is large, located subterminally on U3–U5 and has strong, thick cuticular reinforcements. Short cuticular mouth bristles are present inside the mouth ring. Suboral bristles are present around the mouth ring. The pharynx (U3–U28) is narrow and has anterior and posterior dilatations. The anterior dilation is clearly marked and slightly wider than the posterior one (Table 1). The posterior dilatation is weakly marked. A strong reinforcement is present inside the anterior dilatation at U5–U8, composed of three cuticular rods: two thick, slightly curved rods connected to each other anteriorly at a right angle and a thinner transverse rod that connects the free postero-lateral edges of the two thick rods (Fig. 6 B). The pharynx connects to a straight intestine (which extends from U29 to U85) through the small and narrow pharyngeal intestinal junction (U28). The intestine has a distinct short anterior separate section different in form of morphology that adheres directly to the posterior end of the pharynx.</p> <p> <i>......conitnued on the next page......conitnued on the next page</i> The head is wide, and separated from the trunk with a clear neck constriction (Figs. 1, 3–5). The neck transitions into the trunk, which gradually widens to the largest trunk diameter at approximate two-thirds of the length of the trunk (<i>ca</i>. U63). The trunk then gradually narrows up to a clearly marked furca base at U85. Furcal branches are set wide apart (at a distance equal to the width of the trunk at its widest point) (Figs. 1, 3). The furcal indentation is parabolic, and the ends of adhesive tubes point outwards (Figs. 3, 6 A). Furcal appendages are relatively short and conical. Adhesive tubes are long and thin with slightly curved terminal segments and do not taper at the ends. The ends of the adhesive tubes are slightly rounded.</p> <p>The entire body, except for the ventral interciliary field, is covered with one-lobed scales with a strong, high keel that extends along the entire length of the scale and transitions into a short vestigial spine. The vestigial spines slightly and gradually lengthen from the beginning of the head to the widest part of the trunk. Scales form 35–39 longitudinal alternating rows of 23–27 scales per row. The scales on the head and neck are positioned diagonally in the form of rounded arches that converge at the midline of the head. A median row of scales is absent on the posterior head and on the neck regions, instead of one, there are two median longitudinal rows of scales which are positioned relative to each other alternately (Fig. 1). Subsequently, the longitudinal rows of scales on the trunk run parallel to the central row. On the posterior trunk region, before the furca base, the rows form straight arches that gradually converge on the central row of scales. Scales are located close one to another. Their edges meet but do not overlap. Scales differ morphologically in particular body regions. The scales on the head and neck are shaped like narrow, elongated triangles with rounded edges, and they gradually change their shape towards the trunk, transitioning into strong, narrow trapeziums with rounded edges. A single large scale shaped like a rounded triangle is located dorsally, in the central row of scales on the furca base (on U86–U88) (Figs. 1, 6 A). The tip of the single triangular scale points towards the inner furcal indentation. Two pairs of scales completely different from other scales are located on the dorsal and dorsolateral sides of the furcal branches (Fig. 6 A). The first pair is located dorsolaterally on furcal appendages at U86–U88. The scales in the first pair are large and spineless, shaped like circles and have a strong keel that runs along their entire length. The second pair of scales is located dorsally on the inner side of furcal appendages (intrafurcal scales) on U88–U90. These scales are spineless, shaped like long, narrow rectangles with rounded edges and have a strong keel that runs along their entire length (Figs. 1 C, 4C). Scales with small, triangular lamellae are located in three paired longitudinal rows on both body sides along its entire length (Figs. 1–5). Lamellae of a different type emerge ventrally from longitudinal rows of scales located closest to the ciliary bands. Each of these longitudinal rows consists of 33–35 scales with lamellae. The lamellae are large and long and have rounded edges. They reach beyond the body outline.</p> <p>Scales differ in size through the body (see Table 1, Figs. 1–3). The largest scales are located in the central longitudinal row on the trunk. The scales slightly and gradually become smaller from the dorsal side, through the dorsolateral, lateral, ventrolateral and ventral sides, up to the scales near ciliary bands. Furthermore, the scales become smaller from the head to the neck. The scales then become larger from the beginning of the trunk up to its widest point. Scales located beyond the widest point of the trunk become slightly smaller up to the furca base. Scales in the last longitudinal rows adjoining the ciliary bands are positioned diagonally, at an angle of approximately 30° towards the longitudinal body axis. The large lamellae originate from these scales (“hydrofoil scales”).</p> <p>Locomotor ventral cilia form longitudinal bands that extend from U5 to U85 and two separate, oval patches located immediately beyond the hypostomium on U10–U11 (Figs. 1, 4 C). The longitudinal rows of cilia on the head and neck are wider than on the trunk. The ventral interciliary field is covered from about the beginning of the posterior pharynx dilatation (from U18) with narrow, oval scales with clear keels and straight spines. Scales on the ventral interciliary field gradually become larger from the beginning of the body to the widest part of the trunk. Beyond this point they slightly and gradually become smaller up to the furca base (Fig. 1 C). This species has three pairs of terminal scales of the ventral interciliary field (Fig. 1). The first scales are centrally located at U82–U86. These scales are large and shaped like elongated ovals with a strong large keel that runs along their entire length. They have long, straight spines that pass the contour of the furcal indentation. The second pair of scales is located laterally in relation to the first pair at U84–U86. Scales of the second pair are similar in shape to the scales of the first pair but are smaller and have perceptibly shorter spines that pass the contour of the furcal indentation. The third pair is located at U87–U89 laterally in relation to the first and second pairs, next to the inner edges of the ciliary bands. The scales in the third pair are shaped like narrow, elongated ovals and have strong, long keel that extend along their entire length and a short, straight spine.</p> <p>The species has two pairs of dorsal sensory bristles. The first pair is located dorsolaterally on the neck (U26) and emerges from small, round papillae. The second pair emerges from scales with two rounded keels, located on the posterior part of the trunk (U82). These scales are shaped like rounded triangles and do not have a posterior notch.</p> <p> <b>Remarks.</b> The main character which allowed classify the new species as a member of genus <i>Heterolepidoderma</i> Remane, 1927 is body covering by elongated and keeled scales without posterior notches (<i>e.g</i>. Remane 1927; Schwank 1990; Kisielewski 1997; Todaro <i>et</i> Hummon 2008).</p> <p> The presence of scales with lamellae is not a typical trait of species of <i>Heterolepidoderma</i> (see more below), but instead is standard for another genus traditionally placed within the Chaetonotidae, i.e., <i>Halichaetonotus</i> Remane, 1936. Scales with lamellae in other genera are found less frequently.</p> <p> Among all known taxa, <i>H. sinus</i> <b>spec. nov.</b> is the only species that has two types of lamellae: lateral and ventral (Fig. 2). Prior to this study, there were no described species that possessed scales with lamellae located laterally on the body. However, several species of <i>Heterolepidoderma</i> are known to possess scales with lamellae located ventrally. So far hydrofoil scales have been found in such taxa as: <i>H. foliatum</i> Renaud-Mornant, 1967, <i>H. contectum</i> Schrom, 1972, <i>H. axi</i> Mock, 1979, <i>H. jureiense</i> Kisielewski, 1991, <i>H. lamellatum</i> Balsamo <i>et</i> Fregni, 1995 and <i>H. caudosquamatum</i> Grilli, Kristensen <i>et</i> Balsamo, 2009.</p> <p> The presence of the cuticular reinforcement rods (Fig. 6 B) inside the anterior pharynx dilatation is a trait often encountered in species <i>Halichaetonotus</i>, marine representatives of <i>Heterolepidoderma</i> and <i>Aspidiophorus</i> and some <i>Chaetonotus.</i> The cuticular reinforcement is also, albeit rarely, present in freshwater taxa, <i>e.g.</i>: <i>Aspidiophorus squamulosus</i> (Roszczak, 1936); <i>Chaetonotus (Chaetonotus) eximius</i> Kolicka, Kisielewski, Nesteruk <i>et</i> Zawierucha, 2013; <i>Chaetonotus (Hystricochetonotus) furcatus</i> Kisielewski, 1991; <i>Chaetonotus (Chaetonotus) intermedius</i> Kisielewski, 1991 <i>Chaetonotus (Chaetonotus) pawlowskii</i> Kisielewski, 1984; <i>Heterolepidoderma dimentmani</i> Kisielewski, 1999; <i>H. jureiense</i> Kisielewski, 1991; and <i>H. joermungandri</i> Kånneby, 2011. Various taxa differ greatly from <i>H. sinus</i> <b>spec. nov.</b> in terms of the structure and shape of cuticular reinforcements of the pharynx (Fig. 6 B).</p> <p> <i>H. sinus</i> <b>spec. nov.</b> has a stronger, more clearly marked anterior pharynx dilatation than posterior one. This trait is common among numerous marine species, <i>e.g.</i> <i>Aspidiophorus ornatus</i> Schrom, 1972; <i>Chaetonotus (Chaetonotus) apechochaetus</i>, Hummon, Balsamo <i>et</i> Todaro, 1992, <i>Chaetonotus (Chaetonotus) tempestivus</i> Mock, 1979, <i>Halichaetonotus etrolomus</i> Hummon, Balsamo <i>et</i> Todaro, 1992, <i>Halichaetonotus thalassopais</i> Hummon, Balsamo <i>et</i> Todaro, 1992, <i>Heterolepidoderma arenosum</i> Kisielewski, 1988, <i>Heterolepidoderma contectum</i> Schrom, 1972, <i>Heterolepidoderma clipeatum</i> Schrom, 1972, <i>Heterolepidoderma foliatum</i> Renaud-Mornant, 1967 and <i>Lepidodermella limogenum</i> Schrom, 1972. This trait is also present in freshwater species that are considered as evolutionarily young and that likely underwent specialisation in marine waters to later colonise freshwater environments, <i>e.g.</i> <i>H. dimentmani</i> Kisielewski, 1999 (see Kisielewski 1999) and <i>H. jureiense</i> Kisielewski, 1991, which was found in Brazilian mangrove (see Kisielewski 1991).</p> <p> <b>Differential diagnosis.</b> <i>Heterolepidoderma sinus</i> <b>spec. nov.</b> most closely resembles marine <i>H. axi</i> Mock, 1979, <i>H. foliatum</i> Renaud-Mornant, 1967 and <i>H. contectum</i> Schrom, 1972, <i>H. clipeatum</i> Schrom, 1972, brackish <i>H. caudosquamatum</i> Grilli, Kristensen <i>et</i> Balsamo, 2009 and <i>H. jureiense</i> Kisielewski, 1991 as well as freshwater <i>H. lamellatum</i> Balsamo <i>et</i> Fregni, 1995 and <i>H. joermungandri</i> Kånneby, 2011. However all of this species differ significantly from new described (Table 2).</p> <p> <b>TABLE 2.</b> Condensed comparison of the most important differential characters between <i>Heterolepidoderma</i> representatives the most similar to <i>Heterolepidoderma sinus</i> spec. nov. NA – data</p> <p>available; – – not applicable</p> <p> Character <i>H. sinus</i> spec. <i>H. axi H. foliatum H. conectum H. clipeatum H. caudosquamatum H. jureienense H. lamellatum H. joermungandri</i></p> <p>nov.</p> <p>Body length (µm) 114.23– 110–130 70–80 115 125 114–118 80–112 74.6–92.0 94–105 128.45</p> <p>Cephalic pleuria Cephalion Cephalion Cephalion Cephalion, Cephalion and Cephalion wide; Cephalion Cephalion Cephalion wide; wide; very narrow; wide; epipeuria, hypostomium epipleuria very small wide; wide; epipleuria very epipleuria epipleuria epipleuria hypopleuria absent; only and weakly marked epipleuria epipleuria and small and weakly very small and absent; and one paire of in the head outline; absent; hypopleuria marked in the head and weakly hypopleuria hypopleuria hypostomium large pleuria hypopleuria large and hypopleuria well marked in outline; marked in the unmarked; large and well absent present well marked; large and well the head hypopleuria large head outline; hypostomim marked; hypostomium present marked; outline; and well marked; hypopleuria present hypostomim hypostomim hypostomium hypostomium large and well absent present present present marked;</p> <p>hypostomium</p> <p>present</p> <p> Furca length (µm) 17.52–19.30 <i>ca</i>. 16 <i>ca</i>.16–17 22 24 16–18 <i>ca</i>.17 8.5–11.3 13–15</p> <p> Length of 12.15–13.94 10 <i>ca</i>. 13 NA 21 NA 9.5–11 7.5 7–8</p> <p>adhesive tube</p> <p>µm)</p> <p>Lateral lamellae Present Absent Absent Absent Absent Absent Absent Absent Absent</p> <p>presences</p> <p>Ventral lamellae Present Present Present Present Present Present Present Present Absent</p> <p>presences</p> <p>Distribution and Emerge Present from Emerge From the From the Emerge ventrally Emerge Emerge –</p> <p>type of ventral ventrally from the neck area ventrally from middle of the middle of the from entire ventrally from ventrally from</p> <p>lamellae entire to the end of entire trunk and their trunk and their longitudinal rows of entire entire longitudinal trunk and longitudinal edges do not edges do not scales located closest longitudinal longitudinal rows of scales develop from rows of scales reach beyond reach beyond to the ciliary bands; rows of scales rows of scales located spines and located closest the lateral body the lateral body their edges do not located closest located closest closest to the keels; the to the ciliary edges edges reach beyond the to the ciliary to the ciliary ciliary bands; ends of bands; large lateral body edges bands; large bands; short, large and long spines and and long and and long and their edges do and have keels extend have rounded have rounded not reach rounded edges beyond the edges edges beyond the posterior lateral body lamella edge edges</p> <p>Anterior dilatation Yes Yes Yes Yes Yes No Yes No,both No</p> <p>stronger than dilatation are</p> <p>posterior one similar</p> <p> <i>.......continued on the next page</i> <b>TABLE 2.</b> (Continued)</p> <p> Character <i>H. sinus</i> spec. <i>H. axi H. foliatum H. conectum H. clipeatum H. caudosquamatum H. jureienense H. lamellatum H. joermungandri</i></p> <p>nov.</p> <p>Presents of Present Present Present Present Present Present Present Present Present</p> <p>cuticular</p> <p>reinforcements</p> <p>on the</p> <p>pharynx</p> <p>Number of scales 23–27 23 20 15 20 27–29 19–24 22–27 22–23 single</p> <p>longitudinal row</p> <p>number of 35–39 25–27 27–28 NA NA 25–27 35 17–23 21–22</p> <p>longitudinal</p> <p>alternating rows</p> <p>scales</p> <p>of scales With strong, With a With strong, With keel that With long keel With strong, long Scale edges not With long keel With long keel and long keel that sharply cut long keel that continues into and without keel that continues clearly marked, and without without vestigial continues into posterior continues into a short, vestigial spines into a short, vestigial (only a strong vestigial spines spines a short, edge and a short, vestigial spine spine keel is</p> <p>vestigial spine without vestigial spine marked), keels</p> <p>vestigial without</p> <p>spines vestigial spines</p> <p>Alignment of Edges Edges Edges Edges overlap Edges overlap Edges juxtaposed but NA Edges Edges juxtaposed</p> <p>scales juxtaposed overlap juxtaposed but do not overlap juxtaposed but but do not overlap</p> <p>but do not do not overlap do not overlap overlap</p> <p>Presence of a Present Present Absent Absent Absent Present Absent Absent Present</p> <p>single scale of a</p> <p>different type on</p> <p>dorsal side of</p> <p>furca base&

Aspidiophorus lamellophorus Balsamo, Hummon, Todaro et Tongiorgi 1997

<i>Aspidiophorus lamellophorus</i> Balsamo, Hummon, Todaro <i>et</i> Tongiorgi, 1997 <p>(Figs. 7–8; Table 3)</p> <p> <b>Locality. Southern Baltic Sea,</b> outer Puck Bay, Jastarnia (N54° 41.4 E 18°40.9)</p> <p> <b>Material.</b> Four specimens (all adult), 2 of which were photographed. The microphotographs are available in the Natural History Collections at Adam Mickiewicz University in Poznań under access number NHC-GAL- 11-1- 10 and in the collection of the first author.</p> <p> <b>Short description.</b> <i>Aspidiophorus lamellophorus</i> is a species with a slender body, weakly marked neck constriction and narrow furca base. The head is short, semi-circular and five-lobed. The cephalion (U1–U3) is narrow and short and adheres to the head along its entire length. Epipleuria (U3–U4) are small and almost Character Ranges on adults specimens SD</p> <p>Body length 112.78–117.35 3.231</p> <p>Pharynx length 30.70–31.03 0.233</p> <p>Width of anterior pharynx thickening (a) 8.16–9.09 0.658</p> <p>Width of pharynx narrowing that follows anterior thickening (n) 5.72–6.09 0.262</p> <p>Width of pharynx at its middle length (m) 6.66–6.74 0.057</p> <p>Width of posterior pharynx thickening (p) 7.88–8.88 0.707</p> <p>Length of cephalic cilia (anterior tuft) (4.08–4.18)–(18.75–18.81) 0.071; 0.042 Length of cephalic cilia (posterior tuft) (6.25–6.46)–(18.36–18.71) 0.148; 0.247 Hypostomium length 3.19–3.54 0.247</p> <p>Hypostomium width 8.27–8.53 0.184</p> <p>Cephalion length 6.41–6.67 0.184</p> <p>Cephalion width 10.16–10.68 0.367; 0.696 Diameter of mouth ring 4.95–5.23 0.198</p> <p>Furca length 18.60–18.77 0.120</p> <p>Length of adhesive tube 10.40–10.49 0.064</p> <p>Head scale length (1.67–1.73)–(2.17–2.39) 0.042; 0.156 Head scale width (2.13–2.17)–(2.69–2.72) 0.028; 0.021 Neck scale length (2.03–2.27)–(2.43–2.59) 0.170; 0.113 Neck scale width (2.50–2.64)–(2.88–3.01) 0.099; 0.092 Trunk scale length (2.10–2.35)–(3.01–3.53) 0.177; 0.368 Trunk scale width (2.70–2.89)–(3.64–4.03) 0.134; 0.276 Length of head ventral lamella (5.23–5.39)–(6.74–6.93) 0.113; 0.134 Width of head ventral lamella (2.16–2.52)–(2.38–2.88) 0.255; 0.354</p> <p>.. <i>....continued on the next page</i> Second pair of posteriormost interciliary field scale length 9.15–9.25 0.071 Second pair of posteriormost interciliary field scale width 2.53–2.72 0.134 Number of ventral scales witch lamella in single longitudinal 35–39 2.828 row</p> <p>Total number of longitudinal alternating rows of scales 31–32 0.707 Total number of longitudinal alternating rows of scales on 11 0 interciliary field</p> <p> Pharynx formula a <i>26.58–29.29</i> 1.919 Pharynx formula n <i>18.433–19.837</i> 0.993 Pharynx formula m <i>21.463–21.954</i> 0.347 Pharynx formula p <i>25.667–28.617</i> 2.086 Ratio of scale distribution <i>60.78–71.43</i> 7.531</p> <p>unmarked in the body outline. Hypopleuria (U5–U8) are approximately three times larger than the epipleuria, flat and weakly marked in the head outline. The epipleuria are located dorsally and dorsolaterally, and the hypopleuria are located ventrolaterally. Ocellar granules are not present. The hypostomium (U5–U7) is wide and shaped like a square with rounded edges. It does not have reinforcements. Two pairs of cephalic ciliary tufts are present on the head. Each anterior tuft has four cilia that emerge around the dorsal edges of the epipleuria on U4/5. The first cilium in both anterior tufts is the shortest. The second cilium is very long (the longest of all cilia in the tuft). Two subsequent cilia are shorter than the second cilium but longer than the first one. Each posterior tuft has six cilia. The posterior tufts are located dorsally and emerge in a line directly beyond the ventral edges of epipleuria on U4/ 5. The first cilia emerge close to the cilia in the anterior tufts. The cilia gradually lengthen from the first cilium to the last one (see Table 3). The mouth ring is small and narrow and located subterminally on U2–U4. It has short cuticular reinforcements and is surrounded by suboral bristles. The pharynx (U4–U31) is narrow. Its anterior dilatation is clearly marked and stronger than the weakly marked posterior dilatation (Fig. 8 B). A weak reinforcement composed of a thin, strongly curved single cuticular rod is present inside the anterior dilatation on U6–U7. The pharynx connects to a straight intestine (U32–U88) through the pharyngeal-intestinal junction (U32). The junction is narrow and short. The intestine does not have a distinct anterior separate section different in form of morphology.</p> <p>The head is similar in width to the trunk and separated from it by an indistinctly narrower neck (Fig. 7). The trunk slightly and gradually widens to its widest point located about its middle (U57). The trunk then gradually narrows up to a narrow, weakly marked furca base on U87. Furcal branches are close to each other. The furcal indentation is parabolic, and the ends of adhesive tubes point outwards. Adhesive tubes are straight, long and thin and do not taper towards their ends. The ends of the adhesive tubes are blunt.</p> <p>The entire body, except for the ventral interciliary field, is covered with small pedunculated scales (Figs. 7, 8 A). The scales form 31–35 longitudinal alternating rows of 49–51 scales in each. The scales have a keel and are rhomboidal with a clearly marked peduncle base. They are regularly spaced, and their edges meet. Scales with lamellae form longitudinal rows located closest to ciliary bands, with 35–39 scales in each row. The lamellae are shaped like narrow rectangles and reach beyond the body edges.</p> <p>Scales on the body vary slightly in size (see Table 3). They slightly and gradually become smaller from the dorsal side, through the dorsolateral, lateral, ventrolateral and ventral sides, to the ciliary bands. Furthermore, the scales become larger from the beginning of the head to the widest point of the trunk. Scales in the last longitudinal rows adjoining the ciliary bands are aligned diagonally at an angle of around 20° towards the bands.</p> <p>On the ventral body side, locomotor cilia form longitudinal rows that run from U8 to U81 (Fig. 8 C). The longitudinal rows of cilia on the head and neck are wider than on the other body parts. The ventral interciliary field is covered with narrow, spineless scales with a clearly marked keel starting from about the beginning of the anterior pharynx dilatation (from U11). The scales of the ventral interciliary field are located close to one another, and their edges do not overlap. These scales are shaped like rectangles with slightly rounded edges. Scales on the ventral interciliary field gradually become larger from the front of the body to the widest part of the trunk, beyond which they slightly and gradually become smaller up to the furca base. The species has three pairs of terminal scales of the ventral interciliary field. The first, central pair of terminal scales is located on U86–U88. These scales are shaped like elongated ovals with a strong, long keel that runs along their entire length, and do not have spines. The second pair of scales is located on U84–U87, above and laterally in relation to the first pair. Scales in the second pair are similar in shape to those in the first one but are larger. The third pair (U87–U92) is located laterally in relation to the other two pairs on furcal appendages and is smaller than the others pairs. Scales in the third pair are shaped like narrow ovals. They are spineless and have a long, straight keel that runs along their entire length.</p> <p>The species has three pairs of dorsal sensory bristles (Fig. 8 A). The first pair is located on the head, directly beyond the epipleuria (U5), and emerges from small, round papillae. The second pair is located dorsolaterally on the neck (U32) and emerges from small, round papillae as well. The third, posterior pair emerges from rhomboidal scales with two rectangular keels, located dorsolaterally on the posterior part of the trunk (U85–U86).</p> <p> <b>Taxonomic remarks.</b> All the specimens of <i>Aspidiophorus lamellophorus</i> found in the Puck Bay correspond well with the original description. However, the adult individuals are slightly larger than the Italian specimens (112.8–117.4 Μm, compared to 109 Μm) and have a five-lobed, rather than three-lobed head (two pairs of pleuria are present, however, the epipleuria are small and very weakly marked), a hypostomium and three pairs of dorsal sensory bristles, instead of one pair. Furthermore, a weak cuticular reinforcement is present inside the anterior pharynx dilatation. The differences in body size may result from different environmental conditions (<i>e.g.</i> lower water temperature, lower salinity and different sources of food). The observed differences of other traits may also represent phenotypic variability.</p> <p> <b>Emended differential diagnosis.</b> <i>Aspidiophorus lamellophorus</i> is one of two species belonging to <i>Aspidiophorus</i> that has lamellae. In original description of <i>A. lamellophorus</i> authors (Balsamo <i>et al</i>. 1997) not considered first species with lamellae from genus <i>Aspidiophorus</i> i. e. marine <i>A. bisquamosus</i> Mock, 1979, therefore the comparison contained below is necessary.</p> <p> <i>A. lamellophorus</i> shares with <i>A. bisquamosus</i> the following traits: the presence of ventral lamellae, pedunculated scales with clearly marked peduncle base and keel, body shape (no clearly marked neck narrowing) and a similar body size. However, it differs from <i>A. bisquamosus</i> in terms of the type and shape of lamellae (in <i>A. bisquamosus</i>, lamellae develop from spines and a keels. Spines and keels ends arise beyond lamellae posterior edges. Lamellae are smaller, shorter and shaped like an elongated tear and do not reach beyond the lateral body edges), the type, shape and alignment of scales (in <i>A. bisquamosus</i>, the scales are shaped like shields with rounded lower edges, are ornamented with three small dots on each scale and their edges overlap), the presence of scales of a different type on the furca base (on the furca base <i>of A. bisquamosus</i>, a pair of large scales with a long keel are present; these scales adhere to the cuticle with their entire surface) and the number, shape and alignment of terminal scales of the ventral interciliary field (in <i>A. bisquamosus</i>, four pairs of terminal scales of the ventral interciliary field are present, the second and third pairs are located one on top of the other, the fourth pair located on the inner side of the furcal branches and the second, third and fourth pairs possess spines).</p> <p> <b>Distribution.</b> Previously, the species was recorded only at its <i>locus typicus</i> in the Adriatic Sea (Balsamo <i>et al.</i> 1997; Todaro <i>et al.</i> 2003). The species was found in the mouth of the Isonzo River.</p>Published as part of <i>Kolicka, Małgorzata, Jankowska, Emilia & Kotwicki, Lech, 2015, Baltic Sea Gastrotricha — one new species and one new record of Chaetonotida from Poland, pp. 487-508 in Zootaxa 4027 (4)</i> on pages 501-505, DOI: 10.11646/zootaxa.4027.4.2, <a href="http://zenodo.org/record/232762">http://zenodo.org/record/232762</a&gt