| Raosentis | |
|---|---|
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Acanthocephala |
| Class: | Eoacanthocephala |
| Order: | Gyracanthocephala |
| Family: | Quadrigyridae |
| Subfamily: | Pallisentinae |
| Genus: | Raosentis Datta, 1947 |
Raosentis is a genus of Acanthocephala (thorny-headed worms, also known as spiny-headed worms) that parasitize the intestine of fish.
The National Center for Biotechnology Information does not indicate that any phylogenetic analysis has been published on Raosentis that would confirm its position as a unique order in the family Quadrigyridae. [1]
The genus Raosentis is characterized by the trunk spines are restricted to anterior region only (not divided into two separate regions). The anterior trunk has 16-17 circles of spines and 4 circles of proboscis hooks with anterior two circles larger than posterior two circles; and a spineless space between 2nd and 3rd circles. Species in the genus have a small fusiform body with small hypodermic nuclei arranged in 4 or 5 pairs dorsally and 1 or 2 ventrally. The proboscis is globular to elongate with four circles of proboscis hooks, anterior two circles of hooks longer and shorter than posterior two circles with hookless free space in between. The proboscis sheath is single layered with ganglion at base. The Anterior trunk has 16-17 circles of rose-thorn spines. Testes contiguous, tandem, and near the posterior extremity. Cement gland syncytial with 8-10 nuclei. Vagina has two sphincters. Eggs are small and elliptical. Species are distinguished by 1. Ratio of size of proboscis hooks. [2]
| Female measurements (mm) | ||||||
|---|---|---|---|---|---|---|
| Measurements | R. cavasii | R. dattai [2] | R. godavarensis | R. ivaniosi [2] | R. podderi [2] | R. thapari [2] |
| Length of proboscis | ||||||
| Width of proboscis | ||||||
| Length of proboscis receptacle | ||||||
| Width of proboscis receptacle | ||||||
| Length of trunk | 1.54-2.74 | 2.0-7.0 | ||||
| Width of trunk | 0.45-0.90 | 0.85-2.0 | ||||
| Length of small rootless spines | ||||||
| Length of lemnisci | ||||||
| Size of eggs | 0.040-0.045 x 0.02-0.022 | 0.040-0.060 x 0.020-0.030 | 0.039-0.04 x 0.02-0.022 | |||
| Male measurements (mm) | ||||||
| Length of proboscis | ||||||
| Width of proboscis | ||||||
| Length of proboscis receptacle | ||||||
| Width of proboscis receptacle | ||||||
| Length of trunk | 1.5-5.0 | |||||
| Width of trunk | 0.3-0.67 | |||||
| Length of small rootless spines | ||||||
| Length of lemnisci | ||||||
| Size of anterior testis | ||||||
| Size of posterior testis | ||||||
| Size of cement glands | 0.21-0.25 x 0.18-0.20 | 0.120-0.200 x 0.200-0.250 | 0.32-0.52 × 0.16-0.35 | 0.28–0.33 × 0.13–0.20 | ||
There are six valid species in the genus Raosentis. [3] [4] [5]
Found infesting Mystus cavasius and named after the host of the species cavasius. [5]
R. dattai was found infesting the intestine of the Eutropiichthys vacha in the Gomti river in Lucknow. Male has a small body small with hypodermic nuclei 4-5 pairs dorsally and 2-3 pairs ventrally, 2.68 x 0.7 Proboscis 0.24 x 0.18.· armed with 4 circles of hooks arranged in 6,6,8,8 per row. 1st circle of hooks 0.060-0.065; 2nd 0.055-0.058; 3rd 0.020-0.025. Proboscis sheath 0.61 x 0.15. L/I--O.70 x 0.10; L/2--O.75 x 0.08. Anterior trunk spines extending up to anterior testes. T /1--0.34 x 0.32; T /2--0.32 x 0.28. Eggs are oval. [2]
Found infesting the striped dwarf catfish (Mystus vittatus) and named after the river it was found Godavari. [7]
R. ivaniosi was found infesting the small intestine of the Flatmouth sea catfish (Arius platystomus) in Veli Lake, Puvar and Vellayani, Kerala. Proboscis 0.110-0.160 x 0.040-0.075, armed with 4 circles of 8-10 hooks each, 1st and 2nd circles larger and stouter than 3rd and 4th circle s, larger hooks of 1st circle 0.060-0.090 x 0.004-0.008; 2nd 0.050-0.058 x 0.004-0.007; 3rd 0.030-0.046 x 0.003-0.005; 4th 0.024-0.035 x 0.002-0.005; roots of 1st and 2nd circles of hooks 0.016-0.018. L/1-O.370-0.380 x 0.020-0.040; L/2-D.300-0.350. Proboscis sac 0.180-0.200; T /1-0.200-0.260 x 0.175-0.250; T /2-D.300-0.350 x 0.200-0.300. [2]
It is the first species to be described in the genus Raosentis and is the type species. [3] It was found infesting the small intestine of Mystus cavassius and intestine of the striped dwarf catfish (Mystus vittatus) in river Godavari. Body 1.70–2.76 × 0.37–0.47; proboscis 0.32–0.42 × 0.07–0.075; large hooks 0.66; smaller hooks 0.01; leminsci 0.38–0.42 × 0.04–0.07; testes 0.25-0.28 × 0.20–0.24; cement reservoir 0.15–0.23 × 0.12–0.16 and eggs 0.04-0.05 × 0.02–0.022. [7] Original description from Datta (1947 ) : Male: Body 0.67-2.37. Proboscis hooks 6 in 1st and 2nd circle; 7 in 3rd and 4th circle. hypodermal nuclei 2 dorsal and 1 ventral. anterior trunk spines in 16-17 circles. Cement gland cyncytial with 8-10 nuclei Female: Body 1.31-2.53. Two tubular vagina. Eggs 0.050 x 0.020. [2]
'R. thapari distinguished from R. podderi mainly on the number of hypodermic nuclei on dorsal and ventral trunk. It was found infesting the small intestine of the striped dwarf catfish (Mystus vittatus) in river Godavari (Gorakhpur. Mathura) and the freshwater Zig-zag eel (Mastacembelus armatus). Body 1.18–1.58 × 0.27–0.32; proboscis 0.28–0.32 × 0.07– 0.21; larger hooks 0.06; smaller posterior hooks 0.01–0.02; leminsci 0.30-0.38 × 0.09–0.10; testes 0.15–0.27 × 0.13– 0.18; cement reservoir 0.11–0.16 × 0.09–0.15; eggs 0.03-0.04 × 0.02–0.022. [7] Egg length also given as 39.5 with an elongation ratio of 1.88. [10] Older measurements from Rai (1967) found the male with a Body size of 1.7-2.37 x 0.57-0.68. Proboscis 0.14-0.24 x 0.11-0.16, armed with 4 circles, anterior two circles with 6 hooks each, while, posterior two circles with 8 hooks each, non-spined area between 2nd and 3rd circles 0.058-0.078. 1st circle of hooks 0.085; 2nd 0.058; 3rd 0.028; 4th 0.020. Trunk spines anterior with 9 rows of 25-30 each. Proboscis sac 0.39-0.56 x 0.097-0.11, ganglion at base. Lemnisci equal, 0.55 x 0.075, hypodermic nuclei dorsally and ventrally 3 pairs. T /1-0.25-0.27 x 0.27-0.5. T /2- 0.26-0.33 x 0.31-0.35. [2]
The life cycle of an acanthocephalan consists of three stages beginning when an infective acanthor (development of an egg) is released from the intestines of the definitive host and then ingested by an arthropod, the intermediate host. Although the intermediate hosts of Gyracanthocephala are not known, the order Gyracanthocephala often has Crustaceans as the intermediate host. When the acanthor molts, the second stage called the acanthella begins. This stage involves penetrating the wall of the mesenteron or the intestine of the intermediate host and growing. The final stage is the infective cystacanth which is the larval or juvenile state of an Acanthocephalan, differing from the adult only in size and stage of sexual development. The cystacanths within the intermediate hosts are consumed by the definitive host, usually attaching to the walls of the intestines, and as adults they reproduce sexually in the intestines. The acanthor are passed in the feces of the definitive host and the cycle repeats. Although paratenic hosts (hosts where parasites infest but do not undergo larval development or sexual reproduction) are found in the order Gyracanthocephala, none have been described for Raosentis species. [12]
Raosentis species infest fish.
Acanthocephala is a group of parasitic worms known as acanthocephalans, thorny-headed worms, or spiny-headed worms, characterized by the presence of an eversible proboscis, armed with spines, which it uses to pierce and hold the gut wall of its host. Acanthocephalans have complex life cycles, involving at least two hosts, which may include invertebrates, fish, amphibians, birds, and mammals. About 1420 species have been described.
Apororhynchus is a genus of small parasitic spiny-headed worms. It is the only genus in the family Apororhynchidae, which in turn is the only member of the order Apororhynchida. A lack of features commonly found in the phylum Acanthocephala suggests an evolutionary branching from the other three orders of class Archiacanthocephala; however no genetic analysis has been completed to determine the evolutionary relationship between species. The distinguishing features of this order among archiacanthocephalans is a highly enlarged proboscis which contain small hooks. The musculature around the proboscis is also structured differently in this order. This genus contains six species that are distributed globally, being collected sporadically in Hawaii, Europe, North America, South America, and Asia. These worms exclusively parasitize birds by attaching themselves around the cloaca using their hook-covered proboscis. The bird hosts are of different orders, including owls, waders, and passerines. Infestation by an Apororhynchus species may cause enteritis and anemia.
Gigantorhynchus is a genus of Acanthocephala that parasitize marsupials, anteaters, and possibly baboons by attaching themselves to the intestines using their hook-covered proboscis. Their life cycle includes an egg stage found in host feces, a cystacanth (larval) stage in an intermediate host such as termites, and an adult stage where cystacanths mature in the intestines of the host. This genus is characterized by a cylindrical proboscis with a crown of robust hooks at the apex followed by numerous small hooks on the rest of the proboscis, a long body with pseudosegmentation, filiform lemnisci, and ellipsoid testes. The largest known specimen is the female G. ortizi with a length of around 240 millimetres (9.4 in) and a width of 2 millimetres (0.08 in). Genetic analysis on one species of Gigantorhynchus places it with the related genus Mediorhynchus in the family Gigantorhynchidae. Six species in this genus are distributed across Central and South America and possibly Zimbabwe. Infestation by a Gigantorhynchus species may cause partial obstructions of the intestines, severe lesions of the intestinal wall, and may lead to death.
Mediorhynchus is a genus of small parasitic spiny-headed worms. Phylogenetic analysis has been conducted on two known species of Mediorhynchus and confirmed the placement along with the related genus Gigantorhynchus in the family Gigantorhynchida. The distinguishing features of this order among archiacanthocephalans is a divided proboscis. This genus contains fifty-eight species that are distributed globally. These worms exclusively parasitize birds by attaching themselves around the cloaca using their hook-covered proboscis. The bird hosts are of different orders.
Moniliformidae is a family of parasitic spiny-headed worms. It is the only family in the Moniliformida order and contains three genera: Australiformis containing a single species, Moniliformis containing eighteen species and Promoniliformis containing a single species. Genetic analysis have determined that the clade is monophyletic despite being distributed globally. These worms primarily parasitize mammals, including humans in the case of Moniliformis moniliformis, and occasionally birds by attaching themselves into the intestinal wall using their hook-covered proboscis. The intermediate hosts are mostly cockroaches. The distinguishing features of this order among archiacanthocephalans is the presence of a cylindrical proboscis with long rows of hooks with posteriorly directed roots and proboscis retractor muscles that pierce both the posterior and ventral end or just posterior end of the receptacle. Infestation with Monoliformida species can cause moniliformiasis, an intestinal condition characterized as causing lesions, intestinal distension, perforated ulcers, enteritis, gastritis, crypt hypertrophy, goblet cell hyperplasia, and blockages.
Moniliformis is a genus of parasitic worms in the Acanthocephala phylum.
Oligacanthorhynchida is an order containing a single parasitic worm family, Oligacanthorhynchidae, that attach themselves to the intestinal wall of terrestrial vertebrates.
Arhythmacanthidae is a family of parasitic worms from the order Echinorhynchida.
Dendronucleata is a genus of small parasitic spiny-headed worms. It is the only genus in the family Dendronucleatidae. This genus contains three species that are distributed globally, being collected in North America and Asia. The distinguishing features of this genus among Archiacanthocephalans is the presence of randomly distributed dendritically branched giant hypodermic nuclei. Dendronucleata parasitize freshwater fish and a salamander by attaching themselves in the intestines using their hook covered proboscis and adhesives secreted from cement glands.
Australiformis is a monotypic genus of acanthocephalans containing a single species, Australiformis semoni, that infests marsupials in Australia and New Guinea. Its body consists of a proboscis armed with hooks which it uses to pierce and hold the gut wall of its host, and a long trunk. This genus resembles species in the genus Moniliformis but is characterized by a lack of spiral muscles in the outer wall of the proboscis receptacle. The proboscis is armed with 12 rows of 13 to 15 hooks which are used to attach themselves to the small or large intestines of the host. The female worms range from 95 to 197 millimetres long, virtually all of which is the trunk, and 1.75 to 3.5 millimetres wide. There is pronounced sexual dimorphism in this species as females are around twice the size of the males whose trunks range from 46 to 80 millimetres long and 2 millimetres (0.079 in) wide. Infestation by A. semoni may cause debilitating inflammation of the stomach (gastritis) with granulomatous ulcers.
Heptamegacanthus is a monotypic genus of acanthocephalans. It contains a single species, Heptamegacanthus niekerki, parasite of the endangered giant golden mole found in South Africa. Its body consists of a proboscis armed with hooks which it uses to pierce and hold the rectal wall of its host, and a short, wide trunk. The proboscis is armed with 40 to 45 hooks arranged in rings that are not radially symmetrical, with seven large anterior hooks. The hooks in the anterior ring are twice as large as those in second ring and the remaining hooks decrease progressively in size posteriorly. The worms are about 4 millimetres (0.2 in) long and 2 millimetres (0.08 in) wide.
Pachysentis is a genus in Acanthocephala that parasitize primates and carnivorans. They are distributed across Africa, the Middle East, and the Americas. Pachysentis species attach themselves to the inner lining of the gastrointestinal tract of their hosts using their hook-covered proboscis. Their life cycle includes an egg stage found in host feces, a cystacanth (larval) stage in an intermediate host such as the Egyptian cobra, and an adult stage where cystacanths mature in the intestines of the host. This genus appears identical to the closely related Oncicola apart from a greater number of hooks on the proboscis. There are eleven species assigned to this genus, although P. septemserialis is of uncertain taxonomic status. The female worms range from 12 millimetres (0.47 in) long and 1.6 millimetres (0.063 in) wide in P. lauroi to 50 millimetres (2.0 in) long and 4 millimetres (0.16 in) wide in P. dollfusi. Virtually all of the length is the trunk, with a short proboscis. There is pronounced sexual dimorphism in this species as females are around twice the size of the males.
Oligacanthorhynchus is a genus of parasitic worms belonging to the family Oligacanthorhynchidae.
Atactorhynchus is a genus in Acanthocephala which contains two species, A. verecundus and A. duranguensis.
Golvanacanthus is a monotypic genus of acanthocephalans containing a single species, Golvanacanthus blennii, that infests animals.
Pararaosentis is a monotypic genus of acanthocephalans containing a single species, Pararaosentis golvani.
Triaspiron is a monotypic genus of acanthocephalans containing a single species, Triaspiron aphanii.
Pallisentis is a genus in Acanthocephala.
Intraproboscis is a monotypic genus of acanthocephalans that infest African black-bellied pangolin in the Central African Republic. Its body consists of a proboscis armed with hooks which it uses to pierce and hold the gut wall of its host, and a long trunk. It contains a single species, Intraproboscis sanghae. This genus resembles species in the genus Mediorhynchus but is characterized by infesting a mammal instead of birds, and having a simple proboscis receptacle that is completely suspended within the proboscis, the passage of the retractor muscles through the receptacle into the body cavity posteriorly, absence of neck, presence of a parareceptacle structure, and a uterine vesicle. The proboscis is armed with 34–36 rows of 6 to 7 hooks anteriorly and 15–17 spinelike hooks posteriorly which are used to attach themselves to the intestines of the host. The female worms are up to 180 millimetres long, virtually all of which is the trunk, and 2 millimetres wide.
Mayarhynchus is a monotypic genus of acanthocephalans containing a single species, Mayarhynchus karlae, that infests animals.