University of Plymouth PEARL https://pearl.plymouth.ac.uk 01 University of Plymouth Research Outputs University of Plymouth Research Outputs 1996-11-01 Amphibolous weglarskae Dastych, a new addition to the Tardigrada of Iceland with an updated checklist of Icelandic species (Eohypsibiidae, Eutardigrada). Marley, NJ http://hdl.handle.net/10026.1/12098 Quekett Journal of Microscopy All content in PEARL is protected by copyright law. Author manuscripts are made available in accordance with publisher policies. Please cite only the published version using the details provided on the item record or document. In the absence of an open licence (e.g. Creative Commons), permissions for further reuse of content should be sought from the publisher or author. Quekett Journal of Microscopy, 1996, 37, 541-545 541 Amphibolus weglarskae (Dastych), a new addition to the Tardigrada of Iceland with an updated checklist of Icelandic species. (Eohypsibiidae, Eutardigrada) N. J. MARLEY & D. E. WRIGHT Department of Biological Sciences, University of Plymouth, Drake Circus, Plymouth, Devon, PL4 8AA, England. Summary slides in the Morgan collection held at the During the examination of the extensive Tardigrada National Museums of Scotland, Edinburgh. collections held at the Royal Museums of Scotland, Due to the very sparse number of records specimens and sculptured eggs belonging to Amphibolus available on the Tardigrada from Iceland it weglarskae (Dastych) were identified in the Morgan was considered a significant find. An updated Icelandic collection. This species had not previously taxonomic checklist to Iceland's tardigrada been reported from Iceland. A checklist of Icelandic species has been included because of the Tardigrada species is also provided. progress made since Morgan (1980) on the systematics of the entire phylum. Introduction . Results THE Tardigrada are microscopic animals which Amphibolus weglarskae (Dastych) can be found around the world in a very wide Occurrence: Olasfsjordur, near Siglufjordur. variety of habitats including marine, brackish, Slide reference: Ice 18/S254 Aug. '75, from freshwater and terrestrial interstitial systems. the Morgan Collection held at the National As a phylum they show great diversity in their Museums of Scotland. feeding, reproductive and survival strategies. Feeding preferences range from bacteria and plant cells for some species, to Description Rotifer a, Nematoda and other Tardigrada Twenty-four specimens including fourteen for carnivorous species. There are even a eggs were examined. The specimens were well few parasitic species, including Tetrakentron preserved, although some were positioned synaptae Cuenot which lives on the tentacles underneath the edge of the coverslip and of the sea cucumber, Leptosynapta galienei covered by the transparent ringing material. Herapath, in the English Channel, (Ramazzotti The cuticle of the hatched specimens was & Maucci 1983). During unfavourable micro- smooth and without obvious pigmentation, climate conditions many of the freshwater unfortunately, however, many of the techniques species encyst until optimal conditions return. used for preserving Tardigrada dissolve their However, terrestrial species have been shown pigmentation. The claws were of the distinctive to have remarkable survival abilities. Many of Amphibolus-type, with the basal tract, primary the terrestrial species can retract their legs and and secondary arms clearly defined, Fig 1. shrink their bodies into a barrel-shaped tun. The primary arms had two well developed Inside this structure they lose almost all of accessory points. Smooth lunules were present their water content and can then either be at the base of all the claws. On each of the first dispersed by the wind to a more favourable three pairs of legs, two long thin cuticular bars niche, or remain quiescent until the return of were positioned posterior to the lunules of the more favourable conditions. Once optimal double claws. The buccal tube was short, rigid conditions have returned and rehydration has and relatively wide, (54.7].lm by 9.1].lm in a taken place, active life rapidly resumed. specimen 457].lm long). The buccal aperture was A summary of the few previous Icelandic surrounded by fourteen peribuccallamellae, but Tardigrada references was given by Morgan these were not visible on all specimens. The (1980). The present new addition to the aperture at the top of the buccal tube was wide Icelandic fauna record was identified from and deep, with a posterior band of teeth, 542 N. J. MARLEY & D. E. WRIGHT FIG 1. Claws on leg II of Amphibolus weglarskae (Dastych). Bare l Oprn FIG 2. Buccopharyngeal apparatus of Amphibolus variable in size and shape. The apophysis for weglarskae (Dastych). Bar=20pffi the insertion of the stylet muscles were large Discussion ridges without the sub-divisions discussed by This species had not previously been recorded Biserov (1992). The pharyngeal bulb contained in Iceland, however it had been reported large apophysis and three macroplacoids. in Poland, Greenland and Norway (Dastych, The macroplacoids were rod-shaped, the 1988). This species may have had a wide- second the shortest and the third the longest. spread distribution in Iceland and was The first two macroplacoids were touching in probably euryhydric or hydrophillic. During many specimens, thereby appearing as a single unfavourable micro climatic conditions, ie when very large macroplacoid with a heavy medial the interstitial water was lost, this species was constriction. The latter condition was reported recorded to form cysts, (Marley, unpublished). by some authors as the first two macroplacoids In addition to the A. weglarskae specimens looking similar to the number 1. There was examined on the slide, there were 2 specimens no microplacoid or septulum. The large and one sculptured egg belonging to Macro- furcae of the stylet supports had pronounced biotus harmsworthi. However, it should be lateroventral processes terminating with bulbous noted that the label on the slide indicated that expansions with a reticulate surface, Fig 2. Macrobiotus harmsworthi and Macrobiotus The identification of this species was pullari were present. Macrobiotus pullari was facilitated by the presence of a large number of transferred to another genus by Bertolani & sculptured eggs. None of the eggs contained Pilato (1988), and should now be referred to as well developed embryos. They ranged in Murrayon pullari (Murray). No specimens of diameter, excluding projections, from 77jlm to the latter species were present on the slide, 10Sjlm, projections were up to 37jlm high. The therefore the specimens identified as M. pullari species-specific chorionic pr jections consisted were in fact A. weglarskae. Murrayon pullari of a network of inter-connecting membranous had previously been reported in Iceland by walls which had a fine reticulate sculpturing on De Connick (1939). their surface. The egg surface between the membranous projects was reticulate with Checklist of Icelandic Tardigrada species approximately five or six irregularly shaped Since Morgan (1980), the nomenclature for pores per partitioned section the Tardigrada has been reorganised many Amphibolus weglarskae (Dastych), a new addition to the Tardigrada of Iceland 543 times. The following checklist, based on the micrographs of two eggs, (Morgan, 1982). In nomenclature used in Ramazzotti & Maucci light of Biserov (1990a, b) and Bertolani & (1983), includes relevant modifications pub- Rebecchi (1993) it was assumed that more than lished since that monograph being incorporated. one species from the Macrobiotus hufelandi The literature referenced for the new taxa group was present within the Icelandic fauna. designated since Morgan (1980) are as follows: Of the remaining amendments presented Echiniscidae, Testechiniscus (Kristensen, 1987); below: Pseudechiniscus tridentifer Bartos has Eohypsibiidae, Amphibolus (Bertolani, 1981; been synonymised with Pseudechiniscus victor Bertolani & Kristensen, 1987); H ebesuncus, (Ehrenberg) Dastych (1980); Isohypsibius sattleri Mesocrista, Diphascon (Diphascon), Diphascon (Richters) was designated as a nomen nudum in (Adropion), Itaquascoriinae (Pilato, 1987); Ramazzotti & Maucci (1983) in favour of Diphasconinae (Dastych, 1992); Pseudobiotus, Isohypsibius bakonyiensis (Richters), but this was Minibiotus, Dactylobiotus (Schuster et al, 1980); revised by Dastych (1990) who recognised Ramazzottius (Binda and Pilato, 1986); 1. sattleri as a valid species following the M urrayon (Bertolani and Pilato, 1988). re-discovery of some of Richters' preserved The designations of the sub-genera Macro- material. The status of Dactylobiotus macronyx biotus (Macrobiotus) and Macrobiotus (Ortho- remained in question, Ramazzotti & Maucci macrobiotus), (Biserov, 1990a, b), have not (1983) left the status open, as did Morgan (1980). been included within this checklist, due to the More recently, Biserov (1991), reclassified his questions raised in Bertolani and Rebecchi records of D.macronyx to Dactylobiotus (1993). Morgan (1980) noted that the processes selenicus Bertolani. Until specimens of all on the eggs of Macrobiotus hufelandi were questioned species can be re-examined they have variable and later published scanning electron all been left on the fauna list. TABLE 1 Checklist of Icelandic Tardigrades. Class Heterotardigrada Order Echiniscoidea reported by Morgan (1980) as Family Echiniscidae Bryodelphax parvulus Thulin Echiniscus (Bryodelphax) Echiniscus blumi Richters Echiniscus