Citation: Ciobanu DA, Zawierucha K, Moglan I, Kaczmarek Ł (2014) Milnesium berladnicorum sp. n. (Eutardigrada, Apochela, Milnesiidae), a new species of water bear from Romania. ZooKeys 429: 1–11. doi: 10.3897/zookeys.429.7755
In a lichen sample collected from a tree in Bârlad town (Vaslui County, Romania), a new tardigrade species belonging to the genus Milnesium (granulatum group) was found. Milnesium berladnicorum sp. n. is most similar (in the type of dorsal sculpture) to Milnesium beasleyi Kaczmarek et al., 2012 but differs from it mainly by having a different claw configuration and some morphometric characters. Additionally, the new species differs from other congeners of the granulatum group by the different type of dorsal sculpture, claw configuration and some morphometric characters.
Europe, new species, Palearctic, Tardigrada, taxonomy
In Romania, studies on tardigrades were rather fragmentary and with a significant discontinuity in time (last 40 years). Even though during this period more than 150 taxa (species and subspecies) were reported for this region (
In a lichen sample collected by the first author in Bârlad town in July, 2013, 53 individuals and two exuvia (with 16 eggs) of the new species were found. Additionally, 55 specimens of Ramazzottius oberhaeuseri (Doyère, 1840) were found in the same sample, including 9 specimens in simplex stage and 9 eggs.
All specimens were extracted according to
Body length was measured from the mouth to the end of the body excluding the hind legs. The buccal tube and claws characteristics were measured according to
Characteristics and measurements of the species used in the differential diagnosis are given according to the original descriptions (
Morphometric data were handled using the ''Apochela'' ver. 1.1 template available from the Tardigrada Register (
http://zoobank.org/FBF8C785-2B53-48B2-B696-D442BAD89A0F
http://www.tardigrada.net/register/0014.htm
Holotype (female), 52 paratypes and 2 exuvia with 7 and 9 smooth eggs.
(measurements and statistics in Table 1). Body brownish (in live specimens) or transparent (in fixed specimens) with eyes (visible before and after mounting in Hoyer’s medium - 90% of fixed specimens had eyes). Six peribuccal papillae (ventral papilla smallest) and six peribuccal lamellae (of equal size) around the mouth opening present. Two cephalic papillae positioned laterally. The cuticle is covered with numerous tiny, shallow and rounded depressions (pseudopores) (Figs 4–5). Under PCM these pseudopores are visible as light spots, placing the species within the granulatum group. Bucco-pharyngeal apparatus of the Milnesium type (Fig. 6). Buccal tube funnel-shaped, wider anteriorly (on average the posterior diameter is 73% of the anterior diameter). Pharyngeal bulb elongated, pear-shaped and without placoids or septulum. Claws of the Milnesium type, slender (Figs 2–3). Primary branches on all legs with small accessory points on the top of the branch. Secondary claws of all legs with rounded basal thickenings (lunules) (sometimes barely visible) (Fig. 3). Secondary branches of external claws I–III and posterior and anterior claws IV with two points. Secondary branches of internal claws I–III with three points (i.e. claw configuration: [2-3]-[2-2]) (Figs 2–3). Single, long transverse, cuticular bars under claws I–III present (Fig. 2).
Smooth, deposited in exuvia.
No males were found.
46°14.74167N, 27°40.27333E; 99 m asl: Romania, Vaslui County, Bârlad town, coppice, lichens (Xanthoria parietina (L.) Th. Fr. (1860)) from tree.
This new species is named after the Berladnici, an ancient population with a controversial origin (most probably Slavs) who previously lived in the area of the present Bârlad town.
Holotype (female; slide: P8-8) and 29 paratypes (females) and 1 exuvium with eggs (slides: P8-4, P8-5, P8-6, P8-9, P8-13, P8-14, P8-15, P8-17, P8-19) are preserved at the Department of Animal Taxonomy and Ecology, A. Mickiewicz University in Poznań, Umultowska 89, 61–614 Poznań, Poland. Additionally, 14 paratypes (females) and 1 exuvium with eggs (slides: P8-1, P8-3, P8-16, P8-18) are deposited at Natural History Museum of “Alexandru Ioan Cuza” University from Iași (Bd. Independentei No.16, 700101), 4 paratypes (females; slides: P8-7, P8-12) are deposited at collection of Binda and Pilato (Museum of the Department of Animal Biology “Marcello La Greca”, University of Catania, Italy) and 5 paratypes (females; slides: P8-2, P8-10, P8-11) are deposited at the Natural History Museum, University of Copenhagen Universitetsparken 15, DK-2100 Copenhagen, Denmark.
Milnesium berladnicorum sp. n. Habitus (ventral view). (Scale-bar measurement in µm.)
Milnesium berladnicorum sp. n.: 2 claws III 3 claws IV 4 sculpture on dorsal cuticle above II–III pair of legs 5 sculpture on dorsal cuticle above IV pair of legs 6 buccal apparatus (ventral view). (Scale-bar measurements in µm.)
The administrative map of Romania with 13 highlighted counties in which species of the genus Milnesium were reported: Milnesium tardigradum sensu lato (according with
Measurements and pt values of selected morphological structures of fifteen females from the type population of Milnesium berladnicorum sp. n.
CHARACTER | N | RANGE | MEAN | SD | Holotype | ||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
µm | pt | µm | pt | µm | pt | µm | pt | ||||||
Body length | 15 | 400 | – | 734 | 1557 | – | 1942 | 622 | 1742 | 107 | 127 | 630 | 1619 |
Peribuccal papillae length | 15 | 4.0 | – | 7.9 | 14.8 | – | 20.5 | 6.2 | 17.4 | 1.2 | 1.6 | 7.0 | 18.0 |
Lateral papillae length | 15 | 3.6 | – | 6.9 | 12.7 | – | 17.9 | 5.2 | 14.5 | 1.0 | 1.6 | 5.6 | 14.4 |
Buccal tube | |||||||||||||
Length | 15 | 24.7 | – | 41.5 | – | 35.7 | – | 5.3 | – | 38.9 | – | ||
Stylet support insertion point | 15 | 17.2 | – | 28.3 | 66.6 | – | 71.2 | 24.6 | 69.2 | 3.6 | 1.3 | 27.4 | 70.4 |
Anterior width | 15 | 8.9 | – | 17.8 | 35.0 | – | 47.1 | 14.8 | 41.3 | 3.0 | 3.4 | 16.4 | 42.2 |
Standard width | 15 | 7.8 | – | 14.7 | 30.6 | – | 38.9 | 12.0 | 33.5 | 2.2 | 2.3 | 12.7 | 32.6 |
Posterior width | 12 | 7.2 | – | 13.6 | 27.7 | – | 36.0 | 11.0 | 30.3 | 1.8 | 2.2 | 11.5 | 29.6 |
Standard width/length ratio | 15 | 31% | – | 39% | – | 33% | 2% | – | 33% | ||||
Posterior/anterior width ratio | 12 | 69% | – | 79% | – | 73% | 3% | – | 70% | ||||
Claw 1 lengths | |||||||||||||
External primary branch | 14 | 10.0 | – | 18.0 | 40.5 | – | 47.6 | 15.6 | 43.9 | 2.5 | 2.2 | 17.6 | 45.2 |
External base + secondary branch | 14 | 10.2 | – | 15.9 | 32.9 | – | 45.3 | 13.9 | 39.3 | 2.0 | 3.0 | 14.6 | 37.5 |
External spur | 0 | – | – | – | – | – | – | – | – | ||||
Internal primary branch | 14 | 9.9 | – | 18.1 | 38.1 | – | 45.6 | 14.8 | 41.8 | 2.3 | 2.2 | 15.6 | 40.1 |
Internal base + secondary branch | 14 | 9.9 | – | 15.0 | 33.9 | – | 41.7 | 13.1 | 37.3 | 1.8 | 2.2 | 13.2 | 33.9 |
Internal spur | 9 | 3.0 | – | 4.7 | 9.0 | – | 12.5 | 4.0 | 11.2 | 0.6 | 1.1 | 3.5 | 9.0 |
Claw 2 lengths | |||||||||||||
External primary branch | 15 | 11.5 | – | 20.0 | 43.3 | – | 53.5 | 17.2 | 48.4 | 2.6 | 3.2 | 20.0 | 51.4 |
External base + secondary branch | 15 | 10.4 | – | 16.2 | 36.9 | – | 44.4 | 14.4 | 40.6 | 1.9 | 2.2 | 15.8 | 40.6 |
External spur | 0 | – | – | – | – | – | – | – | – | ||||
Internal primary branch | 15 | 11.4 | – | 18.7 | 39.9 | – | 51.8 | 16.1 | 45.4 | 2.3 | 3.1 | 17.2 | 44.2 |
Internal base + secondary branch | 15 | 9.8 | – | 15.8 | 34.4 | – | 42.5 | 13.5 | 38.0 | 2.0 | 2.7 | 14.4 | 37.0 |
Internal spur | 6 | 2.6 | – | 5.9 | 10.2 | – | 15.6 | 4.1 | 12.4 | 1.2 | 2.2 | ? | ? |
Claw 3 lengths | |||||||||||||
External primary branch | 15 | 11.1 | – | 20.5 | 44.9 | – | 54.8 | 17.6 | 49.5 | 2.8 | 3.1 | 17.9 | 46.0 |
External base + secondary branch | 15 | 9.9 | – | 16.9 | 37.8 | – | 44.5 | 14.6 | 40.9 | 2.2 | 2.1 | 16.4 | 42.2 |
External spur | 0 | – | – | – | – | – | – | – | – | ||||
Internal primary branch | 15 | 10.6 | – | 20.0 | 39.4 | – | 53.7 | 16.5 | 46.4 | 2.8 | 4.5 | 15.5 | 39.8 |
Internal base + secondary branch | 13 | 9.9 | – | 17.6 | 33.6 | – | 45.6 | 13.7 | 38.9 | 2.2 | 3.2 | 15.2 | 39.1 |
Internal spur | 5 | 3.2 | – | 5.3 | 10.6 | – | 14.0 | 4.3 | 12.0 | 0.8 | 1.4 | ? | ? |
Claw 4 lengths | |||||||||||||
Anterior primary branch | 15 | 15.0 | – | 27.0 | 57.9 | – | 74.8 | 22.7 | 63.8 | 3.4 | 4.7 | 24.8 | 63.8 |
Anterior base + secondary branch | 15 | 11.5 | – | 20.2 | 40.0 | – | 50.0 | 16.7 | 46.9 | 2.6 | 3.0 | 18.5 | 47.6 |
Anterior spur | 0 | – | – | – | – | – | – | – | – | ||||
Posterior primary branch | 15 | 14.2 | – | 25.8 | 54.2 | – | 70.4 | 22.1 | 62.0 | 3.4 | 4.6 | 24.0 | 61.7 |
Posterior base + secondary branch | 15 | 11.3 | – | 19.6 | 38.2 | – | 52.2 | 16.5 | 46.2 | 2.9 | 4.0 | 17.4 | 44.7 |
Posterior spur | 0 | – | – | – | – | – | – | – | – |
Due to the sculptured cuticle, Milnesium berladnicorum sp. n. belongs to the granulatum group (
1. Milnesium alabamae Wallendorf and Miller, 2009: by having a different cuticular sculpture (sparse pseudopores on the cuticle which do not form a true reticulum in Milnesium berladnicorum sp. n. vs a finely punctuated (probably pseudopores) cuticle arranged in bands on caudal segments in Milnesium alabamae), a different claw configuration ([2-3]-[2-2] in Milnesium berladnicorum sp. n. vs [3-3]-[3-3] in Milnesium alabamae), the presence of accessory points on primary branches and by presence of eyes.
2. Milnesium beasleyi Kaczmarek, Jakubowska and Michalczyk, 2012: by having a different claw configuration ([2-3]-[2-2] in Milnesium berladnicorum sp. n. vs. [2-3]-[3-2] in Milnesium beasleyi), a different posterior/anterior width ratio (69%–79% in Milnesium berladnicorum sp. n. vs 90%–96% in Milnesium beasleyi) and stylet supports inserted in a more posterior position (pt=66.6–71.2 in Milnesium berladnicorum sp. n. vs pt=61.6–65.6 in Milnesium beasleyi).
3. Milnesium granulatum (Ramazzotti, 1962): by having a different cuticular sculpture (sparse pseudopores on the cuticle which do not form a true reticulum in Milnesium berladnicorum sp. n. vs a reticular sculpture in Milnesium granulatum) and different claw configuration ([2-3]-[2-2] in Milnesium berladnicorum sp. n. vs [3-3]-[3-3] in Milnesium granulatum).
4. Milnesium katarzynae Kaczmarek, Michalczyk and Beasley, 2004: by having a different cuticular sculpture (sparse pseudopores on the cuticle which do not form a true reticulum in Milnesium berladnicorum sp. n. vs a reticular sculpture in Milnesium katarzynae), a different claw configuration ([2-3]-[2-2] in Milnesium berladnicorum sp. n. vs [2-2]-[2-2] in Milnesium katarzynae), larger body size (400–734 µm in Milnesium berladnicorum sp. n. vs 285.0–294.5 µm in Milnesium katarzynae), stylet supports inserted in a more anterior position (pt=66.6–71.2 in Milnesium berladnicorum sp. n. vs pt=73.3–78.3 in Milnesium katarzynae) and by the presence of eyes.
5. Milnesium krzysztofi Kaczmarek and Michalczyk, 2007: by having a different cuticular sculpture (sparse pseudopores on the cuticle which do not form a true reticulum in Milnesium berladnicorum sp. n. vs dorsal cuticle with pseudopores arranged in a fine reticular design in Milnesium krzysztofi), a different claw configuration ([2-3]-[2-2] in Milnesium berladnicorum sp. n. vs [2-3]-[3-2] in Milnesium krzysztofi) and by presence of eyes.
6. Milnesium lagniappe Meyer, Hinton and Dupré, 2013: by the presence of six peribuccal lamellae (four in Milnesium lagniappe), a different cuticular sculpture (sparse pseudopores on the cuticle which do not form a true reticulum in Milnesium berladnicorum sp. n. vs nine dorsal and lateral sculptured bands bearing a reticulated pattern of polygons in Milnesium lagniappe), a different claw configuration ([2-3]-[2-2] in Milnesium berladnicorum sp. n. vs. [2-3]-[3-2] in Milnesium lagniappe), a smaller anterior width of buccal tube (8.9–17.8 µm in Milnesium berladnicorum sp. n. vs 20.7–25.1 µm in Milnesium lagniappe), a smaller standard width of the buccal tube (7.8–14.7 μm in Milnesium berladnicorum sp. n. vs. 19.4–23.6 μm in Milnesium lagniappe), a smaller posterior width of the buccal tube (7.2–13.6 µm in Milnesium berladnicorum sp. n. vs 18.9–23.2 µm in Milnesium lagniappe), a smaller posterior/anterior width ratio (69%–79% in Milnesium berladnicorum sp. n. vs 86%–99% in Milnesium lagniappe) and a smaller standard width/length ratio (31%–39% in Milnesium berladnicorum sp. n. vs 63%–78% in Milnesium lagniappe).
7. Milnesium reticulatum Pilato, Binda and Lisi, 2002: by the lack of dorsal gibbosities, the presence of six peribuccal lamellae (four in Milnesium reticulatum), a different claw configuration ([2-3]-[2-2] in Milnesium berladnicorum sp. n. vs [2-3]-[3-2] in Milnesium reticulatum) and slightly larger body length (400–734 μm in Milnesium berladnicorum sp. n. vs. 270–405 μm in Milnesium reticulatum).
Because of the claw configuration [2-3]-[2-2], Milnesium berladnicorum sp. n. is similar to Milnesium almatyense Tumanov, 2006 (
Until 1990, the genus Milnesium Doyère, 1840 was considered as monotypic with only one described cosmopolitan species, Milnesium tardigradum Doyère, 1840. In 1990, Binda and Pilato described a second species, Milnesium brachyungue from Chile. Later, additional species in the genus Milnesium were described sporadically up to 2006 when Tumanov published the first, but partial, revision of the genus Milnesium and described five new species (
At present the genus Milnesium consists of 21 species and one subspecies (
According to
Including the new species described here, the total number of valid tardigrade taxa recorded in Romania is 128, with three valid Milnesium species (not including Milnesium tardigradum tardigradum sensu stricto, which requires confirmation of presence in Romania).
The authors want to thank Prof. Diane Nelson of East Tennessee State University for help in improving of the English in the manuscript. We are also grateful to anonymous
reviewers for valuable remarks. This work was partially funded by the Prometeo Project of the Secretariat for Higher Education, Science, Technology and Innovation of the Republic of Ecuador. Studies have been partially conducted in the framework of activities of BARg (Biodiversity and Astrobiology Research group) at the Adam Mickiewicz University in Poznań, Poland.