Aiteng ater, Cornelis & Kees & Swennen & Buatip, 2009
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publication ID |
https://doi.org/ 10.5281/zenodo.5342252 |
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persistent identifier |
https://treatment.plazi.org/id/4B1D8781-E926-FFAE-FE88-F8F6BF7BF36D |
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treatment provided by |
Diego |
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scientific name |
Aiteng ater |
| status |
sp. nov. |
Aiteng ater View in CoL , new species
( Figs. 1–2 View Fig View Fig )
Materials examined. – Seven individuals with lengths varying from 6 to 10 mm were found by the authors in the Pak Phanang Bay , in the mangrove forest west of the sand spit between bay and Gulf of Thailand (at 8°29'18"N, 100°10'55"E) on 29 Sep.2007. Dozens of individuals of similar size were found at the same site on 3 Oct.2007. Two individuals in the same size range and two juveniles of 2.0 mm and 2.1 mm were found at the same site on 13 Apr.2008, and about 50 specimens varying in length between 4 and 12 mm on 4 Oct.2008. The description is based on 17 specimens, eight of which were dissected. The holotype and three paratypes are deposited in the Zoological Reference Collection ( ZRC) of the Raffles Museum of Biodiversity Research , National University of Singapore, and three paratypes in the Zoological Museum, University of Amsterdam ( ZMA) GoogleMaps .
Live colouration. – Dorsum grey to black, area around eyes not pigmented ( Figs. 1B,C View Fig , 2A,C View Fig ). Upper foot border, lateral body sides, and underside notum rim grey. Foot sole grey or not pigmented.
External morphology. – Broad, smooth slugs, length 2.5 to 3 times width in creeping specimens ( Fig. 1B,C View Fig ). Body covered by notum with wide free border overhanging foot, but without tentacles, rhinophores, gills, cerata, tubercles or other protuberances ( Figs. 1B,C,D View Fig , 2A,B,C View Fig ). Head with velum and sideward directed eyes under low crests ( Figs. 1D View Fig , 2C View Fig ). Head can be retracted under frontal notum border. Foot sole over whole length divided by deep groove, often kept partly or wholly closed ( Fig. 2B View Fig ). Frontal foot corners not extended, rounded, anterior border smoothly curved, posterior tip rounded, usually not passing notum border, but notum can contract making foot border visible all around. Frontal borders of velum and foot rarely show slight notch. No clear renopericardial bulb. Renopore not located. Male aperture under right eye, female aperture opens besides anus in ventral side of notum rim against anterior right lateral body wall ( Fig. 2C View Fig ).
Internal characteristics. – Nervous system with four prepharyngeal ganglia. Eyes well developed, diameter 125–135 µm, length 180–220 µm, lens spherical ( Fig. 1K View Fig ). Eyes nearly sitting on cerebro pleural ganglion ( Fig. 1E View Fig ). Pharynx yellowish (length 900–1330 µm, height 780–875 µm in 8-11 mm long specimens) voluminous ascus slightly diverging left. Radula uniseriate, one functional tooth; 30–34 teeth in straight ascending limb, 29–33 teeth in curved descending limb, some small, broken teeth in ascus ( Fig. 2F View Fig ). Teeth triangular (height 70–84 µm) with strong median cusp and 6–10 small denticles along lateral border ( Figs.1M View Fig , 2H View Fig ). Teeth in descending limb smaller, by clearly worn cusps. Two large, joined oral glands along ventral side of pharynx. Salivary duct ampullar, curved, laterally entering pharynx ( Fig. 2D View Fig ). Salivary glands consisting of tens of loose, irregularly shaped follicles. ( Fig. 1I View Fig ). Oesophagus short, dark-coloured, from posterior dorsal side of pharynx to simple stomach. Intestine dark pigmented, from anterior right side of stomach to anus. Major branch of digestive gland posteriorly from stomach, sending off side branches that branch several times forming fine network up into free border of notum; branches pale ( Figs. 1F View Fig , 2D View Fig ). Small, dark speckled, digestive follicles on dorsal side of branches ( Fig. 1G View Fig ), covering whole notum under skin, absent above pericardium. Renopericardium mid-frontal under dorsal skin of notum. Transparent dorsal vessels run under skin from near notum border to reno-pericardium ( Figs. 1G View Fig , 2E View Fig ).
Hermaphrodite follicles yellowish, numerous, length 120- 190 µm ( Fig. 1J View Fig ). Connecting ductules gradually unite into hermaphroditic duct continuing through black spotted ampulla ( Fig. 1J View Fig ). Postampullary hermaphroditic duct short; splits into short oviduct and vas deferens. Albumen duct from compound albumen gland ( Figs. 1J View Fig , 2G View Fig ) connects to short oviduct. Fertilisation region, capsule gland and mucus gland very close, distal parts separate; large oviduct could not precisely be traced in these glands. Oviduct and vaginal duct partly united, connected with compact seminal receptacle shortly before female aperture. Vas deferens runs parallel with oviduct to right body wall and then anteriorly; prostate surrounds part of vas deferens curving along and over pharynx ( Figs 1H View Fig , 2G View Fig ), continuing as thin vas deferens to penis sack. Penis thin, unarmed, on right side of head ( Fig. 1L View Fig ).
Endoparasites. – White, cigar-shaped bodies of different sizes were found under the skin and loose on other organs in some specimens during dissecting ( Fig. 1I View Fig ). We supposed these were parasites, but they were not identified or studied.
Habitat and behaviour. – All specimens were found in a dense mangrove forest high in the intertidal zone, not covered by the sea during neap high tides. The slugs were usually along the water level of crab burrows, foot prints, and small pools in rather stiff mud with fallen twigs and leaves. The salinity of the water varied between 18 and 37 S during our visits. The leaf cover of the mangrove trees Avicennia marina (Forsk.) Vierh. , Bruguiera cylindrica (L.) Blume, and Rhizophora apiculata Blume , with an undergrowth of Acanthus ilicifolius L. and Acrostichum aureum L. shaded the substrate from direct sunlight. Specimens kept in the lab usually rested along the water’s edge, often partly in the water, with a preference for small depressions in the mud, which is similar to the field. When they were exposed to strong light, they moved until shade was found. Night observations showed that they were actively moving in the dark, but all movements were slow. Heart beats per 30 s in three moving specimens were 30, 32, and 35 at 32°C. Feeding tests showed that small green algae collected from the site were neglected. However, pupae of insects of the orders Coleoptera and Lepidoptera found in the mud were opened and emptied by the slugs kept in the laboratory. Further trials showed that also imagines of mosquitos and ant larvae were eaten. Copulations and eggs were not seen in the field or laboratory. A few small slugs (length about 2 mm) were discovered in the substrate samples taken to the lab in April 2008. This suggests that reproduction may occur in the beginning of the year shortly after the rainy season.
Etymology. – The specific name is according the colour that looks black on the mud of its habitat.
No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.