TARDIGRADE KEY

Macroversum

Pilato, G. & Catanzaro, R. (1988) Macroversum mirum n. gen. n. sp. Nuovo Eutardigrado (Macrobiotidae) dei Monti Nebrodi (Sicilia). Animalia, 15, 175-180.

Class: Eutardigrada

Order: Parachela

Superfamily: Macrobiotoidea

Family: Murrayidae

Click taxa for descriptions

Genus description from Pilato & Catanzaro 1988: “In ciascuna diplounghia il ramo principale ed il secondario, saldati rigidamente fra loro come in tutti i Macrobiotidae, divergono l’uno dall’altro fin dalla base. La porzione basale è assottigliata come nelle unghie di tipo hufelandi, a formare un esile peduncolo. Il ramo secondario è più corto del principale e forma con esso un angolo quasi retto. Alla base di ciascuna unghia è presente una lunula ben distinta; le due lunule di ciascuna zampa sono collegate fra loro da un ispessimento cuticolare. L’apparato bucco-faringeo è di tipo Macrobiotus, cioè con tubo boccale rigido e provvisto di sbarretta di rinforzo ventrale. La bocca è circondata da lamelle periboccali ed il bulbo faringeo è provvito di apofii e di placoidi.”

Translated with help of Google Translate: In each diploclaw the main and secondary branches, rigidly welded together as in all Macrobiotidae, diverge from each other right from the base. The basal portion is thinned as in hufelandi-type claws, to form a slender peduncle. The secondary branch is shorter than the main one and forms an almost right angle with it. At the base of each claw there is a distinct lunule; the two lunulae of each leg are connected to each other by a cuticular thickening. The bucco-pharyngeal apparatus is of the Macrobiotus type, that is, with a rigid buccal tube and provided with a ventral lamina. The mouth is surrounded by peribuccal lamellae and the pharyngeal bulb is provided with apophyses and placoids.

Pilato, G. & Catanzaro, R. (1988) Macroversum mirum n. gen. n. sp. Nuovo Eutardigrado (Macrobiotidae) dei Monti Nebrodi (Sicilia). Animalia, 15, 175-180.
Pilato, G. & Catanzaro, R. (1988) Macroversum mirum n. gen. n. sp. Nuovo Eutardigrado (Macrobiotidae) dei Monti Nebrodi (Sicilia). Animalia, 15, 175-180.

Citations:

Pilato, G. & Catanzaro, R. (1988) Macroversum mirum n. gen. n. sp. Nuovo Eutardigrado (Macrobiotidae) dei Monti Nebrodi (Sicilia). Animalia, 15, 175-180.

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Claw Symmetry Relative To Median Plane Of Leg?

Image from Bingemer J, Hohberg K. 2017. An illustrated identification key to the eutardigrade species (Tardigrada, Eutardigrada) presently known from European soils. Soil Organisms. 89 (3): 127-149.

Stylet Support Insertion Point As Percentage Of Buccal Tube Length

Stylet support insertion point = ss divided by Buccal tube length, as %. Note anterior measurements begin at anterior margin of stylet sheaths, ss is centred where stylet supports reach buccal tube (this requires a good dorsal or lateral view for proper measurement)

Image from Tumanov DV. 2006. Five new species of the genus Milnesium (Tardigrada, Eutardigrada, Milnesiidae). Zootaxa. 1122: 1-23.

Buccal Tube Long, Mouth At Anterior Of A Protrusible Snout

Images from Pilato G, Binda MG. 2010. Definition of families, subfamilies, genera, and subgenera of the Eutardigrada, and keys to their identification. Zootaxa. 2404: 1-54.

Pharyngeal Tube With Spiral Reinforcement

Images from Pilato G, Binda MG. 2010. Definition of families, subfamilies, genera, and subgenera of the Eutardigrada, and keys to their identification. Zootaxa. 2404: 1-54.

Peribuccal papillae?

Images from Pilato G, Binda MG. 2010. Definition of families, subfamilies, genera, and subgenera of the Eutardigrada, and keys to their identification. Zootaxa. 2404: 1-54.

(Lateral) cephalic papillae, peribuccal papillae, Milnesiidae - type claws, exceptionally wide (and usually short) buccal tube?

Cephalic image modified from Nelson DR, Guidetti R, Rebecchi L. 2009. Tardigrada. Ch. 14 in Ecology and Classification of North American Freshwater Invertebrates, Thorp JH, Covich AP (eds.), 3rd ed.

Claw image modified from Pilato G, Binda MG. 2010. Definition of families, subfamilies, genera, and subgenera of the Eutardigrada, and keys to their identification. Zootaxa. 2404: 1-54.

Pharyngeal tube flexible?

Note: in a tardigrade with snout extended, the flex of the pharyngeal tube may not be obvious.

Images from Pilato G, Binda MG. 2010. Definition of families, subfamilies, genera, and subgenera of the Eutardigrada, and keys to their identification. Zootaxa. 2404: 1-54.

Serrated / dentate cuff / collar on legs IV

Left image from Kristensen RM. 1987. Generic revision of the Echiniscidae (Heterotardigrada), with a discussion of the origin of the family. pp. 261-335 in Bertolani R (ed). Biology of Tardigrades: Selected symposia and monographs.

Right Image from Richters F. 1926. Tardigrada. in Krumbach T. 1927. Handbuch der Zoologie, 3rd band, Walter de Gruyter & Co.

Leg sensory structures

Typically papilla on leg IV (se4 in image) and variable shape on leg I

Image from Kristensen RM. 1987. Generic revision of the Echiniscidae (Heterotardigrada), with a discussion of the origin of the family. pp. 261-335 in Bertolani R (ed). Biology of Tardigrades: Selected symposia and monographs.

Trunk appendages

Appendages (after Cirrus A) labeled according to plate … B (Scapular plate), C (First segmental plate), D (Second segmental plate), E (terminal plate). “B” is lateral, “Bd” is dorsal

Be careful! There can be great variability within a population, with individuals (especially juveniles) lacking some appendages. When in doubt, focus on other characters first!

Left image from Ramazzotti G, Maucci W. 1983. Il phylum Tardigrada(III edizione riveduta e aggiornata). English translation by C. W. Beasley, 1995. Memorie dell’ Istituto Italiano di Idrobiologia 41: 1-1012.

Right image cropped from Kristensen RM. 1987. Generic revision of the Echiniscidae (Heterotardigrada), with a discussion of the origin of the family. pp. 261-335 in Bertolani R (ed). Biology of Tardigrades: Selected symposia and monographs.

Cirrus A form

Images modified from Kristensen RM. 1987. Generic revision of the Echiniscidae (Heterotardigrada), with a discussion of the origin of the family. pp. 261-335 in Bertolani R (ed). Biology of Tardigrades: Selected symposia and monographs.

Lower image (Mopsechiniscus) modified from du Bois-Reymond Marcus E. 1944. Sobre tardigrados brasileiros. Communicaciones Zoologicas del Museo de Historia Natural de Montevideo. 1(13): 1-19 plus plates.

Terminal / caudal plate with two notches?

Images modified from Kristensen RM. 1987. Generic revision of the Echiniscidae (Heterotardigrada), with a discussion of the origin of the family. pp. 261-335 in Bertolani R (ed). Biology of Tardigrades: Selected symposia and monographs.

First image (Echiniscus) modified from Richters F. 1926. Tardigrada. in Krumbach T. 1927. Handbuch der Zoologie, 3rd band, Walter de Gruyter & Co.

Inner & outer buccal cirri present

Image modified from Nelson DR, Guidetti R, Rebecchi L. 2009. Tardigrada. Ch. 14 in Ecology and Classification of North American Freshwater Invertebrates, Thorp JH, Covich AP (eds.), 3rd ed.

Pseudosegmental plate between last medial plate & terminal plate?

Note on 2nd image, what you see before the terminal plate is either no plate, or a full-width medial plate; don’t confuse the latter with a pseudosegmental plate!
Also, sometimes the pseudosegmental plate is paired, like segmental plates II & III. It’s still pseudosegmental!

Images from Clifford HF. 1991. Aquatic invertebrates of Alberta. University of Alberta Press, Alberta, Canada.

Segmental plates larger than intersegmental?

Image modified from Lindahl & Balser (1999), http://www.iwu.edu/~tardisdp/Keypage35.html

Any Paired Plates?

Modified from Lindahl K, Balser S.  1999. Key to tardigrade genera [Internet]. Available from: https://sun.iwu.edu/~tardisdp/Keypage33.html