The metameric pattern of Hypsibius dujardini(Eutardigrada) and its relationship to that of other panarthropods

Smith, F. W.; Jockusch, Elizabeth L.

doi:10.1186/s12983-014-0066-9

Cited by 24 publications

(47 citation statements)

References 61 publications

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“…Postembryonic development is limited to cuticular pores, which are absent in first instar individuals but present in adults thereafter (Figure a,c). These pores (∼50 nm in diameter each) are found in groups and appear to be concentrated around the locations of muscle attachment sites (Figure a,b,d; cf., Smith & Jockusch, ).…”

Section: Resultsmentioning

confidence: 99%

External morphogenesis of the tardigradeHypsibius dujardinias revealed by scanning electron microscopy

Gross

Minich

Mayer

2017

Journal of Morphology

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Tardigrada, commonly called water bears, is a taxon of microscopic panarthropods with five-segmented bodies and four pairs of walking legs. Although tardigrades have been known to science for several centuries, questions remain regarding many aspects of their biology, such as embryogenesis. Herein, we used scanning electron microscopy to document the external changes that occur during embryonic development in the tardigrade Hypsibius dujardini (Eutardigrada, Parachela, Hypsibiidae). Our results show an accelerated development of external features, with approximately 30 hrs separating the point at which external structures first become recognizable and a fully formed embryo. All segments appear to arise simultaneously between ∼20 and 25 hrs of development, and no differences in the degree of development could be detected between the limb buds at any stage. Claws emerge shortly after the limb buds and are morphologically similar to those of adults. The origin of the claws is concurrent with that of the sclerotized parts of the mouth, suggesting that all cuticular structures arise simultaneously at ∼30 hrs. The mouth arises as an invagination in the terminal region of the head at ∼25 hrs, closes later in development, and opens again shortly before hatching. The anlagen of the peribuccal lobes arise as one dorsal and one ventral row, each consisting of three lobes, and later form a ring in the late embryo, whereas there is no indication of a labrum anlage at any point during development. Furthermore, we describe limited postembryonic development in the form of cuticular pores that are absent in juveniles but present in adults. This study represents the first scanning electron micrographs of tardigrade embryos, demonstrating the utility of this technique for studying embryogenesis in tardigrades. This work further adds an external morphological perspective to the developmental data already available for H. dujardini, facilitating future comparisons to related panarthropod taxa. J. Morphol. 278:563-573, 2017. © 2017 Wiley Periodicals, Inc.

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Section: Resultsmentioning

confidence: 99%

External morphogenesis of the tardigradeHypsibius dujardinias revealed by scanning electron microscopy

Gross

Minich

Mayer

2017

Journal of Morphology

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“…; Schulze & Schmidt‐Rhaesa ; Marchioro et al . ; Smith & Jockusch ). Tardigrades and onychophorans thus possess the basic myoanatomical elements from which arthropodan musculature could be derived, with the exception of the dorsoventral and oblique elements of the arthropodan box‐truss (Fig.…”

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confidence: 99%

Onychophoran‐like myoanatomy of the Cambrian gilled lobopodian Pambdelurion whittingtoni

Young

Vinther²

2016

Palaeontology

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Arthropods are characterized by a rigid, articulating, exoskeleton operated by a lever‐like system of segmentally arranged, antagonistic muscles. This skeletomuscular system evolved from an unsegmented body wall musculature acting on a hydrostatic skeleton, similar to that of the arthropods’ close relatives, the soft‐bodied onychophorans. Unfortunately, fossil evidence documenting this transition is scarce. Exceptionally‐preserved panarthropods from the Cambrian Lagerstätte of Sirius Passet, Greenland, including the soft‐bodied stem‐arthropod Pambdelurion whittingtoni and the hard‐bodied arthropods Kiisortoqia soperi and Campanamuta mantonae, are unique in preserving extensive musculature. Here we show that Pambdelurion's myoanatomy conforms closely to that of extant onychophorans, with unsegmented dorsal, ventral and longitudinal muscle groups in the trunk, and extrinsic and intrinsic muscles controlling the legs. Pambdelurion also possesses oblique musculature, which has previously been interpreted as an arthropodan characteristic. However, this oblique musculature appears to be confined to the cephalic region and first few body segments, and does not represent a shift towards arthropodan myoanatomy. The Sirius Passet arthropods, Kiisortoqia and Campanamuta, also possess large longitudinal muscles in the trunk, although, unlike Pambdelurion, they are segmentally divided at the tergal boundaries. Thus, the transition towards an arthropodan myoanatomy from a lobopodian ancestor probably involved the division of the peripheral longitudinal muscle into segmented units.

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“…Immunostaining has been successfully implemented for studies of embryogenesis in H. exemplaris (Gabriel and Goldstein 2007;Gross and Mayer 2015). The protocol presented here is based on immunostaining protocols developed for H. exemplaris embryos (Gabriel and Goldstein 2007) and adults (Smith and Jockusch 2014), an in situ hybridization protocol developed for H. exemplaris (Smith et al 2016), and a method developed to study gene expression in small embryos (Irvine 2007).…”

Section: Methodsmentioning

confidence: 99%

Embryonic Immunostaining for the Tardigrade Hypsibius exemplaris

Smith

Gabriel

2018

Cold Spring Harb Protoc

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Immunostaining is a method used to visualize the localization of proteins in fixed tissue. Many antibodies are available that recognize specific proteins in a wide diversity of organisms, which makes this method ideal for investigating gene expression patterns in nonmodel animal systems. This protocol describes immunostaining for studies of embryogenesis in the tardigrade Hypsibius exemplaris. MATERIALS It is essential that you consult the appropriate Material Safety Data Sheets and your institution's Environmental Health and Safety Office for proper handling of equipment and hazardous materials used in this protocol. RECIPES: Please see the end of this protocol for recipes indicated by . Additional recipes can be found online at http://cshprotocols.cshlp.org/site/recipes. Reagents Antibodies A primary antibody and a fluorescently labeled secondary antibody are used in this protocol. Bovine serum albumin (BSA; 0.2%) Chymotrypsin/chitinase solution Fixative solution for Hypsibius immunostaining Methanol (25%, 50%, 70%, and 90% [v/v] in 0.5× PBT; 100%) Mounting medium with anti-fade reagent (e.g., Fluoromount-G [Invitrogen 00495802]) Normal goat serum (NGS; 5%) PBT (0.5×) Spring water Use commercial bottled spring water found in grocery stores. Do not use tap water; the chlorine and/or chloramine common in tap water is harmful to many microscopic animals.

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The metameric pattern of Hypsibius dujardini(Eutardigrada) and its relationship to that of other panarthropods

Cited by 24 publications

References 61 publications

External morphogenesis of the tardigradeHypsibius dujardinias revealed by scanning electron microscopy

External morphogenesis of the tardigradeHypsibius dujardinias revealed by scanning electron microscopy

Onychophoran‐like myoanatomy of the Cambrian gilled lobopodian Pambdelurion whittingtoni

Embryonic Immunostaining for the Tardigrade Hypsibius exemplaris

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