Uroleptus Ehrenberg, 1831 (ref. ID; 2014, 3925) or Stein, 1859 (ref. ID; 3690)
Class Polyhymenophora: Subclass Spirotricha: Order Hypotrichida: Suborder Stichotrichina: Family Holostichidae (ref. ID; 2014)
Hypotrichida (ref. ID; 7578)

Synonym Cladotricha Gajewskaja, 1925 (ref. ID; 2014); Platytrichotus Stokes, 1886 (ref. ID; 2014)

[ref. ID; 2014]
Narrow elongate body often tapered posteriorly into a tail region. 2 rows of marginal cirri and 2 rows of midventral cirri extending into the frontal region although at least 3 anterior frontal cirri are clearly differentiated. Transverse cirri absent. May or may not possess caudal cirri. The peristome region small (less than quarter body length) in a narrowed frontal region. 2 or 4 macronuclei with associated micronuclei. Several species have been described.
The question of presence of absence of transverse cirri in the genus is controversial. Here we adopt the view of Kahl (1932), with his reservations, rather than Borror (1972), or Jankowski (1979) and reserve the genus Paruroleptus for similar forms with transverse cirri. Jankowski (1978) created a new genus Perisincirra for U. kahli Groliere, 1976. Borror (1979) transferred the genus to the Urostylidae.
Quote; Colin R. Curds, Michael A. Gates and David McL. Roberts "British and other freshwater ciliated protozoa Part II Ciliophora: Oligohymenophora and Polyhymenophora" Cambridge University Press, 1983 (ref. ID; 2014)

[ref. ID; 3925]
Usually one row each of right and left marginal cirri; midventral cirri in typical zigzag series, 2 cirri per original oblique ciliary streak; frontal cirri hypertrophied, similar to Holosticha; transverse cirri often reduced or absent; posterior end of cell narrowed into "tail".
Type Genus (by subsequent designation); Uroleptus musculus (O.F. Muller, 1773) Ehrenberg, 1831
Uroleptus is a poorly understood genus of fresh-water hypotrichs currently plagued by an astoundingly complex nomenclature and dozens of superficially described nominal species. The number of transverse cirri is extremely variable within a clone; indeed many ciliates identified as being in the genus Uroleptus lack transverse cirri. Uroleptus musculus (O.F. Muller, 1773), the type species, possesses midventral cirri homologous to those of Urostyla; hence Uroleptus should be cofamilial with the remainder of this assemblage. Nomenclature of Uroleptus is further clouded by continuing confusion of this ciliate, which has midventral cirri, with vermiform hypotrichs from fresh water, soil, mosses, and hypersaline environments that lack midventral cirri. (ref. ID; 3925)


Uroleptus elongatus Fernandez-Leborans, 1981 (ref. ID; 4695, 7578 original paper)
Description; [Paroral formation]: In this species the paroral formation is divided into two parts: PF 1 and PF 2. Paroral formation 1 (PF 1) has a length of 12 um (avg.) and it is the most anterior and nearest to the oral area, of the two parts of which the paroral formation is composed. PF 1 is made up of a haplokinety composed of 40-48 kinetosomes. Paroral formation 2 (PF 2) measures 15 um (avg.) and it is composed of two parallel rows of 28-29 kinetosomes each. (ref. ID; 4695)
Filiform appearance, very short peristome and two stretched macronuclear formations. (ref. ID; 7578)
[Somatic ciliature]: The somatic ciliature is made up of cirri arranged in the following groups: right marginal cirri, left marginal cirri, right ventral cirri, left ventral cirri, dorsal cirri, caudal cirri and front-buccal field (FBF, Borror 1979). (ref. ID; 7578)
Right marginal cirri. They are lined up in two rows, that extend from the most anterior extreme of AZM to nearness of the posterior end of ciliate. The rightmost row consists of 36 cirri and the anterior one has 33 cirri. Each cirrus has 4 kinetosomes and one thick kinetodesmal fibre. (ref. ID; 7578)
Left marginal cirri. There are two rows of left marginal cirri. The leftmost row extends from the anterior end to the proximity of the posterior end of the ciliate and presents two parts: an anterior one which consists of 14 cirri each of one has 4 kinetosomes and one kinetodesmal fibre: and a posterior one made up of 20 cirri each of one has 2 kinetosomes and a kinetodesmal fibre. The anterior row only has the 3/4 parts of the length of ciliate from the anterior end and it is formed of 29 cirri each of one has 4 kinetosomes and one kinetodesmal fibre. (ref. ID; 7578)
Right ventral cirri. They are arranged in two rows, one shorter than the another one, which extend from the posterior zone of the fronto-buccal field (FBF) towards the posterior end of ciliate. The rightmost row presents two parts: an anterior one consists of 17 cirri each of one has 4 kientosomes and one kinetodesmal fibre, a posterior one made up of 5 cirri, each one with 2 kinetosomes and one kinetodesmal fibre. The another row of this cirri group is formed by 13 cirri, each of one with 4 kinetosomes and a kinetodesmal fibre. (ref. ID; 7578)
Left ventral cirri. The form three rows that extend from the posterior zone of AZM toward the posterior end of ciliate. The row placed between the other two rows and adjacent to AZM is very short and it is made of three cirri, each of one with 4 kinetosomes and one kinetodesmal fibre. The leftmost one of the other two rows consists of 25 cirri each one with 4 kinetosomes an one kinetodesmal fibre and one cirrus with two kinetosomes and kinetodesmal fibre. The rightmost row has 20 cirri each one with 4 kinetosomes and a kinetodesmal fibre. (ref. ID; 7578)
Dorsal cirri. In the middle part of the dorsal side of ciliate according to the anteroposterior axis of ciliate there are 13 cirri each of one with two kinetosomes and a kinetodesmal fibre. (ref. ID; 7578)
Caudal cirri. There are three caudal cirri placed near to the posterior end and more or less in the ventral side of the ciliate, each of one with 2 kinetosomes and a kinetodesmal fibre. (ref. ID; 7578)
Fronto-buccal field. There are six cirri: five frontal cirri and one buccal cirrus; although some specimens have 7-8 cirri in this zone. Each cirrus consists of 9 kinetosomes arranged in three rows, each one with 3 kinetosoems. Two frontal cirri are placed very near to the anterior origin of the two rows of right marginal cirri, other two frontal cirri in the anterior origin of the two rows of right marginal cirri, other two frontal cirri in the anterior origin of the two rows of right ventral cirri and the remaining frontal cirrus is the most midventral. The buccal cirrus is adjacent to the most anterior zone of one of the two paroral kineties or undulating membranes. It must be pointed out that the frontal cirri have thick derivates which might be kinetodesmal fibres. However each cirrus has not only one of these fibres, but some frontal cirri have 2, 3 or 4 fibres and other ones have no fibres. Normaly, the frontal cirri placed nearest to AZM and the buccal cirrus have no kinetodesmal fibres. (ref. ID; 7578)
[Oral infraciliature]: This infraciliature present two types of structures: the adoral zone of membranelles (AZM) and the paroral kineties or undulating membranes (PK1, PK2).
The adoral zone of membranelles. The adoral zone of membranelles consists of around 22 membranelles, each of one is made up of 4 kineties with 3, 10, 14, 14 kinetosomes; that is, there two kineties which are the longest and have the same length, one intermediate kinety and one kinety very short. All of these membranelles are not similar, specially in the anterior and posterior extremes of the AZM, where the number of kinetosomes decreases and each whole membranelle become smaller. For this reason as in other hypotrichous and heterotrichous ciliates the AZM has three different parts (anterior, intermediate and posterior (Fernandez-Leborans and Fernandez-Galiano 1980). (ref. ID; 7578)
The paroral kineties. There are two, one or more anterior than the another one. The most anterior kinety PK1 (endoral) is an haplokinety or stichodiade made up of around 40-48 kinetosomes. The PK2 (paroral) consists of a double kinety which has 58 kinetosomes on average. (ref. ID; 7578)
Remarks; The principal differences between U. kahli Groliere 1975 and U. elongatus are the following features: 1. U. kahli has a reduced paroral membrane constituted by a single row of cilia. U. elongatus presents two paroral kineties, the anterior one is a stichodiade and the other one, posterior to the former, is a double row of kinetosomes. 2. U. kahli had 3 cirri in the front-buccal field, 2 frontal and 1 buccal. U. elongatus had 6 cirri in the front-buccal field: 5 frontal and 1 buccal. 3. U. kahli has 2 rows, right and left, of marginal cirri. U. elongatus present 4 rows of marginal cirri: 2 on the right side and 2 on the left side. 4. U. kahli had two rows of ventral cirri while U. elongatus present 5: 2 at the right side and 3 (one of them very short) at the left side. 5. U. kahli has 3 rows of dorsal cilia. U. elongatus presents only one row of dorsal cirri. 6. U. elongatus has 3 caudal cirri. In U. kahli the caudal cirri are absent. (ref. ID; 7578)
Measurements; Body size 124 x 17 um, AZM length 28 um, membranelle length 4.7 um, PK1 length 12 um, PK2 length 15 um, peristome size 21 x 11 um, cirrus FBF length 1.3 um, length of the four kinetosomes cirrus 0.6 um, length of the two kinetosomes cirrus 0.4 um (on average). (ref. ID; 7578)
Uroleptus halseyi Calkins, 1929 (ref. ID; 1621) reported year? (ref. ID; 1618)
Description; Peristome one-sixth to one-seventh the body length; 3 ventrals; macronucleus divided into many (up to 26) parts; 2 (1-3) micronuclei; fresh water. (ref. ID; 1618)
Measurements; About 160 by 20 um. (ref. ID; 1618)
Uroleptus limnetis Stokes, 1885 (ref. ID; 1621) reported year? (ref. ID; 1618)
Description; Fresh water among vegetation. (ref. ID; 1618)
Measurements; About 200 um long. (ref. ID; 1618)
Uroleptus longicaudatus Stokes, 1886 (ref. ID; 1621) reported year? (ref. ID; 1618)
Description; Marsh water with Sphagnum. (ref. ID; 1618)
Measurements; About 200 um long. (ref. ID; 1618)