Corresponding author: Oscar Lisi (
Academic editor: Sandra McInnes
A new genus of
Lisi O, Daza A, Londoño R, Quiroga S, Pilato G (2019)
Rarely in the study of systematics and phylogeny is one so fortunate to encounter a taxon with characters that sheds light on phylogenetic directions within a group. While studying Colombian tardigrades, from the Sierra Nevada de Santa Marta, we found eight specimens and two exuviae with eggs of a new species of
In the framework of the subfamily Itaquasconine Rudescu, 1964, the four genera
The present work is part of a revision of the tardigradological collection of the Centro de Colecciones Biológicas de la Universidad del Magdalena (
The original specimens had been extracted from moss and lichen samples collected in San Lorenzo and El Campano, Colombia. Complete information about localities and samples studied are included in the description of the new species under Material examined.
The studied specimens were mounted in polyvinyl alcohol mounting media (BioQuip #6371A). Measurements are given in micrometres (µm), and photomicrographs made under ×100 oil immersion under phase contrast and differential interference contrast microscopy, using a Leica “DMLB” Microscope equipped with “Canon S40” digital camera and a micrometre, a Zeiss Axio Scope A1 with CCD camera Zeiss AxioCam ICc5, and a Zeiss AxioLab A1 with a Zeiss Axiocam ERc 5s. Images were edited, and plates arranged, using Adobe Photoshop Elements 2.0 digital imaging software.
Notwithstanding the presence of spiral thickening, we refer to the “buccal tube” as the entire portion of the bucco-pharyngeal tube anterior to the stylet supports, which seems to be almost rigid. A problem of interpretation and terminology with regard to that portion of the bucco-pharyngeal tube is discussed in the Appendix
Morphological measurements for the holotype, five paratypes, and the additional specimen of
No. slide | 00376 | 00477 | 00476 | 00461 | 00545 | 00462 holotype | 00460 |
---|---|---|---|---|---|---|---|
Body length | 303 | 258 | 265 | 482 | 486 | 590 | 515 |
Bucco-pharyngeal tube length | 40.6 | 41.6 | 42.4 | 60.0 | 61.2 | 61.3 | ? |
Buccal tube length | 21.0 | 23.3 | 23.6 | 30.6 | 31.7 | 31.8 | 33.7 |
pbf | 51.7 | 56.0 | 55.7 | 51.0 | 51.8 | 51.9 | ? |
Buccal tube external width | 5.2 | 5.6 | 5.7 | 8.7 | 8.8 | 8.9 | 9.5 |
pt | 24.8 | 24.0 | 24.2 | 28.4 | 27.8 | 28.0 | 28.2 |
pt stylet supports insertion point | 100 | 100 | 100 | 100 | 100 | 100 | 100 |
First placoid | ? | 5.2 | 5.2 | 9.3 | 10.7 | 10.9 | 10.6 |
pt | ? | 22.3 | 22.0 | 30.4 | 33.7 | 34.3 | 31.4 |
Second placoid | ? | 14.3 | 14.5 | 25.6 | 29.0 | 29.0 | 29.0 |
pt | ? | 61.4 | 61.4 | 83.7 | 91.5 | 91.2 | 86.1 |
Placoid row | ? | 20.3 | 20.4 | 34.5 | 40.2 | 40.7 | 40.7 |
pt | ? | 87.1 | 86.4 | 112.7 | 126.8 | 128.0 | 120.8 |
External claw I | 14.5 | ? | 15.4 | 21.4 | 21.3 | ? | ? |
pt | 69.0 | ? | 65.3 | 69.9 | 67.2 | ? | ? |
External claw I - main branch | 10.4 | ? | 11.3 | 15.0 | 15.2 | ? | ? |
pt | 49.5 | ? | 47.9 | 49.0 | 47.9 | ? | ? |
External claw I - main branch % total | 71.7 | ? | 73.4 | 70.1 | 71.4 | ? | ? |
External claw I - base + secondary branch | 6.7 | ? | 7.3 | 11.3 | 11.8 | 12.1 | ? |
pt | 32.2 | ? | 30.9 | 36.9 | 37.2 | 38.1 | ? |
Internal claw I | ? | ? | 9.7 | 14.0 | 13.7 | ? | ? |
pt | ? | ? | 41.1 | 45.7 | 43.2 | ? | ? |
Internal claw I - main branch | ? | ? | 6.1 | 8.6 | 8.5 | ? | ? |
pt | ? | ? | 25,8 | 28.1 | 26.8 | ? | ? |
Internal claw I - main branch % total | ? | ? | 62.9 | 61.4 | 62.0 | ? | ? |
Internal claw I - base + secondary branch | ? | 6.2 | 6.1 | 9.0 | 9.1 | 10.2 | ? |
pt | ? | 26.6 | 25.8 | 29.4 | 28.7 | 32.1 | ? |
External claw II | 15.9 | 16.9 | ? | ? | ? | 29.0 | ? |
pt | 76.4 | 72.5 | ? | ? | ? | 91.2 | ? |
External claw II - main branch | 11.5 | 12.2 | ? | ? | ? | 20.0 | ? |
pt | 55.3 | 52.4 | ? | ? | ? | 62.9 | ? |
External claw II - main branch % total | 72.3 | 72.2 | ? | ? | ? | 69.0 | ? |
External claw II - base + secondary branch | 7.1 | ? | 7.4 | ? | ? | 13.8 | ? |
pt | 34.1 | ? | 31.3 | ? | ? | 43.4 | ? |
Internal claw II | ? | 10.5 | 10.9 | ? | ? | 18.4 | ? |
pt | ? | 45.1 | 46.2 | ? | ? | 57.9 | ? |
Internal claw II - main branch | ? | 7.5 | 7.7 | ? | ? | 12.9 | ? |
pt | ? | 32.2 | 32.6 | ? | ? | 40.2 | ? |
Internal claw II - main branch % total | ? | 71.4 | 70.6 | ? | ? | 70.1 | ? |
Internal claw II - base + secondary branch | ? | 6.6 | 6.3 | ? | ? | 11.2 | ? |
pt | ? | 28.3 | 26.7 | ? | ? | 35.2 | ? |
External claw III | ? | 18.1 | 17.4 | ? | ? | 28.6 | 29.0 |
pt | ? | 77.7 | 73.7 | ? | ? | 89.9 | 86.1 |
External claw III - main branch | ? | 13.0 | 11.8 | ? | 18.2 | 19.5 | 19.6 |
pt | ? | 55.8 | 50.0 | ? | 57.4 | 61.3 | 58.2 |
External claw III - main branch % total | ? | 71.8 | 67.8 | ? | ? | 68.2 | 67.6 |
pt | ? | 36.1 | 33.1 | 38.6 | ? | 42.1 | 39.2 |
Internal claw III | 10.3 | 10.9 | ? | ? | 17.4 | 19.3 | ? |
pt | 49.5 | 46.8 | ? | ? | 54.9 | 60.7 | ? |
Internal claw III - main branch | ? | 7.3 | ? | ? | 11.4 | 12.7 | ? |
pt | ? | 31.3 | ? | ? | 36.0 | 39.9 | ? |
Internal claw III - main branch % total | ? | 67.0 | ? | ? | 65.5 | 65.8 | ? |
Internal claw III - base + secondary branch | ? | 6.6 | 6.3 | ? | ? | 11.4 | 11.1 |
pt | ? | 28.3 | 26.7 | ? | ? | 35.8 | 32.9 |
Posterior claw IV | ? | 20.0 | 20.2 | ? | ? | 30.5 | 30.5 |
pt | ? | 85.8 | 85.6 | ? | ? | 95.9 | 90.5 |
Posterior claw IV - main branch | ? | 14.5 | 14.1 | ? | ? | 21.8 | 21.3 |
pt | ? | 62.2 | 59.7 | ? | ? | 68.6 | 63.2 |
Posterior claw IV - main branch % total | ? | 69.0 | 70.1 | ? | ? | 71.5 | 69.8 |
Posterior claw IV - base + secondary branch | ? | 9.8 | 10.1 | 14.0 | ? | 15.3 | 14.7 |
pt | ? | 42.1 | 42.8 | 45.8 | ? | 48.1 | 43.6 |
Anterior claw IV | ? | 10.9 | 11.0 | 16.2 | ? | 17.6 | 18.1 |
pt | ? | 46.8 | 46.6 | 52.9 | ? | 55.3 | 53.7 |
Anterior claw IV - main branch | ? | 7.7 | 7.7 | 11.3 | ? | 12.1 | 12.2 |
pt | ? | 33.0 | 32.6 | 36.9 | ? | 38.0 | 36.2 |
Anterior claw IV - main branch % total | ? | 70.6 | 70.0 | 69.7 | ? | 68.7 | 67.4 |
Anterior claw IV - base + secondary branch | ? | ? | 9.1 | 12.7 | ? | 13.6 | 13.0 |
pt | ? | ? | 38.6 | 41.5 | ? | 42.8 | 38.6 |
Claws of the
For comparison, we have examined specimens of:
For phylogenetic analysis, a character matrix was prepared and a parsimony analysis applied with a Nearest Neighbor Interchange (
Claws of the
Bucco-pharyngeal tube of
Bucco-pharyngeal apparatus of
According to the definition in
Shape of the stylet furca (arrow ‘a’) in species of various genera of
San Lorenzo, Sierra Nevada de Santa Marta, Magdalena, Colombia.
The holotype and paratypes, and the additional specimen, are deposited in the Centro de Colecciones Biológicas de la Universidad del Magdalena (
Body uncoloured. A faint, though difficult to see, cuticular roughness visible on the caudal portion of the body. Eyes probably absent (definitely absent after mounting and no information record when mounted). Bucco-pharyngeal apparatus of the
We found eight specimens and two exuviae with eggs and it is interesting to note that three specimens were small and of similar body size, whereas the others are markedly longer and certainly adults as demonstrated by the size of the exuviae with eggs. Unfortunately, we have not been able to establish the sex of the specimens; in particular, whether the smallest were three young, or new-born specimens, or were males. It is interesting to note that some metric characters of the smaller specimens are very similar to those of the larger specimens, while others were markedly different (see Table
Body length 590 µm, uncoloured, cuticle with a faint, very difficult to see roughness in the caudal body portion (Fig.
Claws of the
We found two exuviae, one with 5 and the other with 6 smooth eggs.
The specific epithet refers to the term “Aluna” which in Ika, the native language of the Kogui (an Amerindian ethnic group inhabiting the Sierra Nevada de Santa Marta), means the non-visible or spiritual world. Aluna is a name in apposition.
As mentioned above, the three smaller specimens (Fig.
Small specimens (juvenile or male) of
The particular combination of the characters of the bucco-pharyngeal apparatus distinguishes the new species from all known species of
It is unnecessary to compare all
The differences with
We carefully examined
Preliminary discussion
The new genus
Above all, the absence of molecular data for
Taking into account the morphology of the
The first regards the shape of the
A second evolutionary trend regards the shape and size of the stylet furcae. In
A third evolutionary trend regards the stylet supports, which are normally developed in
The fourth evolutionary direction is that of the placoids, which are present, long and slender in
Some of these evolutionary tendencies are also recognisable in the genera
A parsimony analysis of the character matrix shown in Table
Character matrix used for the phylogenetic analysis.
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moderately wide | robust | postero-lateral | “big” with developed branches | swollen | absent | present (slender) | present (normal) |
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moderately wide | robust | lateral | “big” with developed branches | non-swollen | present | present (slender) | present |
|
very wide | thin | lateral | “big” with developed branches | non-swollen | absent | present (slender) | present |
|
very wide | extremely thin, even flexible | lateral | small with reduced branches | non-swollen | absent | reduced to a thin bar or absent | present (slendered) |
|
very wide | extremely thin, even flexible | lateral | small with reduced branches | non-swollen | present | reduced to a thin bar or absent | absent |
Most supported phylogenetic tree, according to character matrix in Table
In choosing the proposed phylogenetic tree, we have been careful not to allow character reversals. However, the spiral thickening on the anterior buccal tube is present in two separate branches of the tree (in
In
It is clear that in all cases, any attempt to reconstruct phylogenetic relationships requires making a hypothesis that can be tested, and which might give rise to doubts or different opinions. We think that a hypothesis can be proposed when clear characters and evolutionary tendencies are observed in known members of a taxon (for which the phylogeny is totally unknown). Such a proposed hypothesis is justified and needs to be brought to the attention of the scientific community, while awaiting new data to confirm or create a new, more convincing, phylogenetic reconstruction.
The present work also adds value to the biodiversity of Colombia, with a new species and a new genus that, at least for the moment, result endemic for the country. It is worth mentioning that we are about to publish another new genus (of a different family) from Colombia, proving the high potential of these investigations, since to date very little is known about the tardigradological fauna of the country. This encourages us to go on with our studies.
We thank Paula Sepúlveda for helping to collecting the samples; Claudia Morales and Kevin R. Roncallo for the identification of the bryophytes and lichens. This work was carried in the framework of the research projects “Diversidad de ositos de agua (Tadigrada) asociados a briófitos y líquenes epífitos en cultivos de café de la Sierra Nevada de Santa Marta, con un enfoque innovador para la apropiación social del conocimiento” and “Ositos de agua (
We are also grateful to the colleagues Roberto Bertolani and Barbara Weglarska who donated many years ago, respectively, the specimens of
The presence in
in Marley et al. 2011; amended by Bertolani et al. 2014 and Gąsiorek et al. 2018
amended by Bertolani et al. 2014 and Gąsiorek et al. 2018
sensu Pilato 1987, amended by Bertolani et al. 2014