Ramajendas

Class : Eutardigrada

Order : Isohypsibioidea

Family : Incerta

Genus : Ramajendas

Isohypsibioidea from Marley et al. 2011: “Parachela. Claws asymmetrical (2121); Isohypsibius-type claw pairs; AISM ridged.”

Isohypsibioidea from Bertolani et al. 2014: “Double claws asymmetrical with respect to the median plane of the leg (2121), normally with similar shape and size on each leg; double claws of the Isohypsibius type (secondary branch of the external claw inserted perpendicularly on the claw basal tract), or reduced from it: Hexapodibius type (very short, without common basal tract, with a base as large as the sum of the primary and secondary branch widths, and with an evident suture between primary and secondary branch); Haplomacrobiotus type (one branch only); completely absent (Apodibius). Buccal tube completely rigid (apart Paradiphascon; see below) and often relatively large, without (Dastychius, Eremobiotus, Halobiotus, Isohypsibius, Paradiphascon, Pseudobiotus, Thulinius) or with (Apodibius, Doryphoribius, Haplomacrobiotus, Haplohexapodibius, Hexapodibius, Parhexapodibius) ventral lamina. Eggs with smooth shell laid within the exuvium.”

Isohypsibiidae from Marley et al. 2011: “Isohypsibioidea. Claw pairs of similar size and shape. External and internal claws exhibiting articulation (the basal section and secondary branch form a solid unit while the primary branch and secondary branch articulate). Claws Isohypsibius-type, forming a right-angle between basal section and secondary branch. AISM ridge-like.”

Genus description from Pilato & Binda 1990: “Hypsibiidae con le due diplounghie di ciascuna zampa extremamente diverse fra loro; quella interna è di tipo Isohypsibius e quella esterna di tipo Hypsibius modificato (il ramo principale, estremamente lungo e sottile, non appare collegato all’unghia basale mediante un tratto sclerificato e flessibile ben definito). Apparato bucco-faringeo con tubo boccale rigido, privo di sbarretta di rinforzo ventrale e con le apofisi per l’inserzione degli stiletti a cresta molto lunga (esso risulta quindi molto vicino al tipo Isohypsibius); mancano lamelle periboccali ben sviluppate e l’organo sensoriale ellittico sul capo; il bulbo faringeo contiene apofisi e placoidi; nelle due specie finora ascrivibili al genere sono presenti alla base delle unghie ispessimenti cuticolari interpretabili come lunule anche se di forma diversa dal solito.”

Translated: Hypsibiidae with the two double-claws of each leg extremely different from each other; the inner one is of Isohypsibius type and the external one of Hypsibius type (the main branch, extremely long and thin, does not appear connected to the claw base by means of a well-defined sclerified and flexible tract). Bucco-pharyngeal apparatus with rigid buccal tube, without ventral reinforcement bar and with apophyses for the insertion of stylet muscles in the form of very long crests (it is therefore very close to the Isohypsibius type); without well-developed peribuccal lamellae and elliptic sensory organ on the head; the pharyngeal bulb contains apophyses and placoids; in the two species so far ascribable to the genus, cuticular thickenings are present at the base claws that can be interpreted as lunules although of a different shape than usual.


Citations :

Ramajendas image cropped from Miller WR, Horning DS, Dastych H. 1995. Tardigrades of the Australian Antarctic: description of two new species from Macquarie Island, Subantarctica. Entomologische Mitteilungen aus dem Zoologischen Museum Hamburg. 11 (152): 231-239.

“Parts” 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.

Bertolani R, Guidetti R, Marchioro T, Altiero T, Rebecchi L, Cesari M. 2014. Phylogeny of Eutardigrada: New molecular data and their morphological support lead to the identification of new evolutionary lineages. Molecular Phylogenetics and Evolution. 76: 110-126.

Marley NJ, McInnes SJ, Sands CJ. 2011. Phylum Tardigrada: A re-evaluation of the Parachela. Zootaxa. 2819: 51-64.

Pilato G, Binda MG. 1990. Tardigradi dell’antartide: I: Ramajendas, nuovo genere di eutardigrado: nujova posizione sistematica di Hypsibius renaudi Ramazzotti, 1972 e descrizione di Ramajendas frigidus n. sp. Animalia. 17: 61-71.

Genus Ramajendas

Isohypsibioidea from Marley et al. 2011: “Parachela. Claws asymmetrical (2121);
Isohypsibius-type claw pairs; AISM ridged.”
Isohypsibioidea from Bertolani et al. 2014: “Double claws asymmetrical with respect to the median plane
of the leg (2121), normally with similar shape and size on
each leg; double claws of the Isohypsibius type (secondary
branch of the external claw inserted perpendicularly on the
claw basal tract), or reduced from it: Hexapodibius type
(very short, without common basal tract, with a base as
large as the sum of the primary and secondary branch
widths, and with an evident suture between primary and
secondary branch); Haplomacrobiotus type (one branch
only); completely absent (Apodibius). Buccal tube
completely rigid (apart Paradiphascon; see below) and often
relatively large, without (Dastychius, Eremobiotus,
Halobiotus, Isohypsibius, Paradiphascon, Pseudobiotus,
Thulinius) or with (Apodibius, Doryphoribius,
Haplomacrobiotus, Haplohexapodibius, Hexapodibius,
Parhexapodibius) ventral lamina. Eggs with smooth shell
laid within the exuvium.”

Isohypsibiidae from Marley et al. 2011: “Isohypsibioidea. Claw pairs of similar size and shape.
External and internal claws exhibiting articulation (the basal section and secondary branch form a solid unit while the
primary branch and secondary branch articulate). Claws Isohypsibius-type, forming a right-angle between basal
section and secondary branch. AISM ridge-like.”

Genus description from Pilato & Binda 1990: “Hypsibiidae con le due diplounghie di ciascuna zampa
extremamente diverse fra loro; quella interna è di tipo Isohypsibius e quella esterna di tipo
Hypsibius modificato (il ramo principale, estremamente lungo e sottile, non appare collegato
all’unghia basale mediante un tratto sclerificato e flessibile ben definito). Apparato bucco-faringeo con
tubo boccale rigido, privo di sbarretta di rinforzo ventrale e con le apofisi per l’inserzione degli
stiletti a cresta molto lunga (esso risulta quindi molto vicino al tipo Isohypsibius); mancano lamelle
periboccali ben sviluppate e l’organo sensoriale ellittico sul capo; il bulbo faringeo contiene apofisi e
placoidi; nelle due specie finora ascrivibili al genere sono presenti alla base delle unghie ispessimenti
cuticolari interpretabili come lunule anche se di forma diversa dal solito.”
Translated: Hypsibiidae with the two double-claws of each leg extremely different from each other;
the inner one is of Isohypsibius type and the external one of Hypsibius type (the main branch,
extremely long and thin, does not appear connected to the claw base by means of a well-defined sclerified
and flexible tract). Bucco-pharyngeal apparatus with rigid buccal tube, without ventral reinforcement bar
and with apophyses for the insertion of stylet muscles in the form of very long crests (it is therefore
very close to the Isohypsibius type); without well-developed peribuccal lamellae and elliptic sensory
organ on the head; the pharyngeal bulb contains apophyses and placoids; in the two species so far ascribable
to the genus, cuticular thickenings are present at the base claws that can be interpreted as lunules although
of a different shape than usual.

Citations
Ramajendas image cropped from Miller WR, Horning DS, Dastych H. 1995.
Tardigrades of the Australian Antarctic: description of two new species from Macquarie Island,
Subantarctica. Entomologische Mitteilungen aus dem Zoologischen Museum Hamburg. 11 (152): 231-239.
“Parts” 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.
Bertolani R, Guidetti R, Marchioro T, Altiero T, Rebecchi L, Cesari M. 2014. Phylogeny of Eutardigrada:
New molecular data and their morphological support lead to the identification of new evolutionary lineages.
Molecular Phylogenetics and Evolution. 76: 110-126.
Marley NJ, McInnes SJ, Sands CJ. 2011. Phylum Tardigrada: A re-evaluation of the Parachela.
Zootaxa. 2819: 51-64.
Pilato G, Binda MG. 1990. Tardigradi dell’antartide: I: Ramajendas, nuovo genere di
eutardigrado: nujova posizione sistematica di Hypsibius renaudi Ramazzotti, 1972 e descrizione
di Ramajendas frigidus n. sp. Animalia. 17: 61-71.

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?

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.

(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, choose “Unclear” to ignore this character!


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?

Images from Kristensen RM. 1987. Generic revision of the Echiniscidae (Heterotardigrada), with a discussion of the origin of the family. pp. 261-335