Pachysentis

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Pachysentis
Pachysentis lenti.jpg
Proboscis of P. lenti[1]
Scientific classification e
Kingdom: Animalia
Phylum: Acanthocephala
Class: Archiacanthocephala
Order: Oligacanthorhynchida
Family: Oligacanthorhynchidae
Genus: Pachysentis
Meyer, 1931

Pachysentis is a genus of Acanthocephala (thorny-headed worms, also known as spiny-headed worms) that parasitize carnivourous mammals 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 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. The eleven species (however, P. septemserialis has an uncertain taxonomic status) in this genus are distributed across Africa and the Americas.

Taxonomy[]

Pachysentis has not been included in phylogenetic analyses thus far,[2] and is categorized based on morphological features. Phylogenetic analyses have been conducted on Oncicola, a genus morphological nearly identical to Pachysentis apart from the number of hooks on the proboscis, and have placed it in the family Oligacanthorhynchidae.

Archiacanthocephala
Archiacanthocephala
Oligacanthorhynchidae
 

Macracanthorhynchus ingens

 
 

Oncicola venezuelensis

 
 

Oligacanthorhynchus tortuosa

 
 

Nephridiacanthus major

 
 
 
Moniliformidae

Moniliformis moniliformis

 
Gigantorhynchida
 

Mediorhynchus sp.

 
 

Gigantorhynchus echinodiscus

 
 
 
 
Phylogenetic reconstruction for select species in the class Archiacanthocephala[3][4]

Description[]

Diagram of a male Pachysentis_lauroi showing the anterior and posterior testes, eight cements glands in a clustered arrangement, the ejaculatory ducts and the retracted copulatory bursa.
Diagram of a male P. lauroi showing the anterior and posterior testes, and eight cements glands in a clustered arrangement.

Pachysentis look identical to the closely related Oncicola apart from the number of hooks on the proboscis. Species of Oncicola have 36 or less hooks whereas species of Pachysentis have more. Specifically, the proboscis is not quite spherical and contains 42 to 102 hooks arranged into 12 longitudinal rows 3 to 12 hooks each. The rows may be regularly or irregularly alternating and straight or crooked. Hooks have tips with or without barbs, and the larger hooks with complex manubria and roots with the remaining spines being rootless. The trunk is fairly wide relative to the length with the anterior half usually wider than the posterior half. The testes are in tandem with at least one located before the middle of the worm. There are eight cement glands compactly arranged each with single giant nucleus used to temporarily close the posterior end of the female after copulation.[5][6] The eggs have a sculptured outer membrane. Species can be distinguished based on the number and arrangements of proboscis hooks, whether these hooks are barbed, the arrangement of the cement glands, host, and the length of lemnisci.[1]

Species[]

P. angolensis
Measurements[1] Female (mm) Male (mm)
Length of proboscis 0.55-0.63
Width of proboscis 0.70–0.82
Length of proboscis receptacle 1.5
Length of trunk 34-48 17-23
Width of trunk 4.8–5.5 3.5–4
Length of lemnisci 5.8–6
Size of anterior testes 2–3 × 0.9
Size of posterior testes 2–4.3 × 1.0
Dimension of group of cement gland - 3
Ejaculatory duct length - 2.3
Size of eggs in mm 0.09 × 0.043 -
P. canicola
Measurements[1] Female (mm) Male (mm)
Length of proboscis 0.57-0.80
Width of proboscis  0.57–0.85
Length of proboscis receptacle 2
Length of trunk 20–26 15-28
Width of trunk 5-11 4-8
Length of lemnisci 7
Size of anterior testes 2
Size of posterior testes 2
Dimensions of cement glands 3
Uterine bell 3. 15–8.15
Size of eggs in mm 0.07 × 0.045
P. dollfusi
Measurements[1] Female (mm) Male (mm)
Length of trunk 50 50 
Width of trunk 4 4
Length of lemnisci 4.3–6.6
Size of eggs in mm 0.08 × 0.05
P. ehrenbergi
Measurements[1] Female (mm) Male (mm)
Length of proboscis 0.8
Width of proboscis 0.9
Length of proboscis receptacle 1.3
Length of trunk 26-29 25
Width of trunk 6 4
Length of lemnisci 7
Width of lemnisci 0.8
Size of anterior testes 3
Size of posterior testes 3
Dimension of group of cement gland 7
Size of eggs in mm 0.07 × 0.05
P. gethi
Measurements[1] Female (mm) Male (mm)
Length of proboscis 0.583
Width of proboscis 0.794
Length of proboscis receptacle 1.07
Width of proboscis receptacle 0.498
Length of trunk 15–25 10–15
Width of trunk 1.5–3 1.0–2.5
Length of lemnisci 3.48
Size of anterior testes 1.40 × 0.581
Size of posterior testes 1.40 × 0.581
Dimension of cement glands 1.54
Ejaculatory duct length 4.64
Uterine bell 5.56
Size of eggs in mm 0.084 × 0.054
P. lauroi
Measurements[1] Female (mm) Male (mm)
Length of proboscis 0.68 × 0.76
Width of proboscis 0.68 × 0.76
Length of proboscis receptacle 1.16 × 0.47
Width of proboscis receptacle 1.16 × 0.47
Length of trunk 12.07 × 1.62 9.63 × 1.91
Width of trunk 12.07 × 1.62 9.63 × 1.91
Length of lemnisci 4.45
Size of anterior testis 1.15 × 0.48
Size of posterior testis 1.27 × 0.55
Dimension of group of cement gland 0.86 × 0.56
Ejaculatory duct length 1.42
Uterine bell 1.19
Size of eggs 0.073 × 0.045
P. lenti
Measurements[1] Female (mm) Male (mm)
Length of proboscis 0.63
Width of proboscis 0.664
Length of proboscis receptacle 1.32
Length of trunk 20–25 15–20
Width of trunk 2–2.5  1.0–2.5
Length of lemnisci 3.15
Size of anterior testis 1.76 × 0.51
Size of posterior testis 1.82 × 0.547
Dimension of group of cement gland 2.98
Uterine bell 1.41
P. procumbens
Measurements[1] Juvenile (mm)
Length of proboscis 0.55
Width of proboscis 0.55
Length of proboscis receptacle 1.2
Length of trunk 6
Width of trunk 1.25
P. procyonis
Measurements[1] Female (mm) Male (mm)
Length of proboscis 0.697 
Width of proboscis 0.716
Length of proboscis receptacle 1.37
Width of proboscis receptacle 0.531
Length of trunk 25-35 20-30 
Width of trunk 2–3 2–3
Length of lemnisci 3.64
Size of anterior testes 3.01 × 1.24
Size of posterior testes 3.15 × 1.07
Dimension of group of cement glands 3.56
Ejaculatory duct length 3.53
Uterine bell 4.64
Size of eggs in mm 0.071 × 0.042
P. rugosus
Measurements[1] Female (mm) Male (mm)
Length of proboscis 0.564
Width of proboscis 0.694
Length of proboscis receptacle 1.24
Width of proboscis receptacle 0.481
Length of trunk 32 25
Width of trunk 3 3.5
Dimension of group of cement glands 2.02
Length of lemnisci 4.64
Size of anterior testes 1.57 × 0.697
Size of posterior testes 1.69 × 0.664
Ejaculatory duct length 2.02
Uterine bell 5.86

The genus Pachysentis Meyer, 1931 contains eleven species, however P. septemserialis has an uncertain taxonomic status.[1][7][a]

  • Pachysentis angolensis (Golvan, 1957)[b]

P. angolensis was found infesting the Side-striped jackal (Canis adustus) in Angola. The proboscis has a total of 42 hooks without barbs arranged in six rows of four hooks followed by six rows of three hooks.[1] The species name angolensis derives from the country, Angola, where it was discovered.[9]

  • Pachysentis canicola Meyer, 1931

P. canicola was found infesting the Red fox (Vulpes vulpes) in Bushehr, Bushehr Province, Iran,[10] P. canicola was also found infesting the golden jackal, (Canis aureus) in Iran.[11] It was also found infesting the Western diamondback rattlesnake. [12][13]

  • Pachysentis dollfusi (Machado-Filho, 1950)

P. dollfusi was found infesting the Common brown lemur (Eulemur fulvus) in a Brazilian zoo but originally from the island of Madagascar. It is thus unknown if the worm originates from Brazil or Madagascar. The proboscis has 48 barbed hooks arranged into six rows of four hooks each followed by six rows of four hooks each. The cement glands are in uniform pairs.[1]

  • Pachysentis ehrenbergi Meyer, 1931

P. ehrenbergi was found infesting the red fox (Vulpes vulpes) in Egypt and in an intermediate host the Egyptian cobra (Naja haje). The proboscis is armed with 102 barbed hooks arranged into six rows of nine hooks each followed by six rows of eight hooks each. .[1]

  • Pachysentis gethi (Machado-Filho, 1950)[14]

P. gethi was originally described in 1950 by Machado-Filho infesting Tayra (Eira barbara) in Pará and Rio de Janeiro, Brazil but this remained the only record until it was rediscovered in 2016 infesting the wild lesser grison (Galictis cuja) also in Rio de Janeiro.[15] The proboscis has 42 hooks without barbs arranged into six rows of four hooks followed by six rows of three hooks. The eight cement glands occur in pairs.[1]

  • Pachysentis lauroi Gomes, Amin, Olifiers, Bianchi, Souza, Barbosa & Maldonado, 2019[1]

P. lauroi has been found infesting the South American coati (Nasua nasua) in Mato Grosso do Sul, Brazil. The proboscis has 48 barbed hooks arranged into six rows of four hooks followed by six rows of four hooks. The eight cement glands are clustered. [1]

  • Pachysentis lenti (Machado-Filho, 1950)

P. lenti has been found infesting the White-headed marmoset (Callithrix geoffroyi) in Espirito Santo, Brazil. The proboscis has 48 hooks without barbs arranged into six rows of four hooks followed by six rows of four hooks.[1]

  • Pachysentis procumbens Meyer, 1931

P. procumbens has been found infesting the red fox (Vulpes vulpes) in Argo, Egypt. The proboscis has 90 hooks without barbs arranged into six rows of seven hooks followed by six rows of eight hooks. [1]

  • Pachysentis procyonis (Machado-Filho, 1950)

P. procyonis was found infesting the Crab-eating raccoon (Procyon cancrivorus) in Rio de Janeiro, Brazil. The proboscis has 42 hooks without barbs arranged into six rows of four hooks followed by six rows of three hooks. Distinguishing features include eight clustered cement glands and very short lemnisci that do not reach the anterior testis.[1]

  • Pachysentis rugosus (Machado-Filho, 1950)

P. rugosus have been found infesting Azaras's capuchin (Sapajus cay) in Rio de Janeiro, Brazil. The proboscis is armed with 42 hooks without barbs arranged into six rows of four hooks each followed by six rows of three hooks each. This species can be identified by their clustered cement glands and long leminisci that reach the anterior testis. [1]

  • Pachysentis septemserialis (Machado-Filho, 1950)

P. septemserialis is considered to have uncertain taxonomic status by Gomes (2019) due to the differences between the paratypes morphological characteristics and those of the original description, the similarity in hosts (primates of the family Callitrichidae), and the absence of samples or measurements of adult males. Specifically, the original description of one paratype described the lack of a collar at the base of the proboscis whereas a collar was observed (suggesting affiliation with the genus Prosthenorchis). A second discrepancy from another paratype is the incorrect number of hooks; 12 longitudinal rows of four hooks with total of 48 hooks were observed but contradicts the seven rows of seven hooks with a total of 49 hooks given in the original description. Morphologically, new observations suggests it is synonymous with P. lenti.[1]

Hosts[]

Pachysentis species exclusively parasitize carnivourous mammals as their primary host. Reptilian intermediate hosts have been found for P. ehrenbergi and P. canicola.

Notes[]

  1. ^ A binomial authority in parentheses indicates that the species was originally described in a genus other than the present genus.
  2. ^ P. angolensis was originally named Oncicola angolensis by Golvan in 1957 but was renamed by Schmidt in 1972 .[7][8]

References[]

  1. ^ a b c d e f g h i j k l m n o p q r s t u v w x Gomes, Ana Paula N.; Amin, Omar M.; Olifiers, Natalie; Bianchi, Rita de Cassia; Souza, Joyce G. R.; Barbosa, Helene S.; Maldonado, Arnaldo (2019). "A New Species of Pachysentis Meyer, 1931 (Acanthocephala: Oligacanthorhynchidae) in the Brown-Nosed Coati Nasua nasua (Carnivora: Procyonidae) from Brazil, with Notes on the Genus and a Key to Species". Acta Parasitologica. 64 (3): 587–595. doi:10.2478/s11686-019-00080-6. PMC 6814649. PMID 31286360.
  2. ^ "Search NCBI databases".
  3. ^ Nascimento Gomes, Ana Paula; Cesário, Clarice Silva; Olifiers, Natalie; de Cassia Bianchi, Rita; Maldonado, Arnaldo; Vilela, Roberto do Val (December 2019). "New morphological and genetic data of Gigantorhynchus echinodiscus (Diesing, 1851) (Acanthocephala: Archiacanthocephala) in the giant anteater Myrmecophaga tridactyla Linnaeus, 1758 (Pilosa: Myrmecophagidae)". International Journal for Parasitology: Parasites and Wildlife. 10: 281–288. doi:10.1016/j.ijppaw.2019.09.008. PMC 6906829. PMID 31867208.
  4. ^ Amin, O.M.; Sharifdini, M.; Heckmann, R.A.; Zarean, M. (2020). "New perspectives on Nephridiacanthus major (Acanthocephala: Oligacanthorhynchidae) collected from hedgehogs in Iran". Journal of Helminthology. 94: e133. doi:10.1017/S0022149X20000073. PMID 32114988.
  5. ^ Bush, Albert O.; Fernández, Jacqueline C.; Esch, Gerald W.; Seed, J. Richard (2001). Parasitism : the diversity and ecology of animal parasites. Cambridge, UK New York, NY: Cambridge University Press. p. 203. ISBN 0-521-66278-8. OCLC 44131774.
  6. ^ Kükenthal, W (2014). Gastrotricha and Gnathifera. Göttingen, Germany: Walter de Gruyter. p. 322. ISBN 978-3110274271.
  7. ^ a b "Oligacanthorhynchidae Petrochenko, 1956". Integrated Taxonomic Information System (ITIS). 20 May 2020. Retrieved 20 May 2020.
  8. ^ Amin, Omar M. (19 September 2013). "Classification of the Acanthocephala". Folia Parasitologica. 60 (4): 273–305. doi:10.14411/fp.2013.031. PMID 24261131.
  9. ^ Golvan YJ (1957) Acanthocéphales de l’Angola. I. Oncicola angolensis n. sp. (Archiacanthocephala, Pachysentidae), parasite du chacal Canis adustus Sundevall. Publicacion Servicos Culturais de la Companhia de Diamantes de Angola, Museo do Dundo 34:39–50
  10. ^ Tavakol, Sareh; Amin, Omar M.; Luus-Powell, Wilmien J.; Halajian, Ali (22 October 2015). "The acanthocephalan fauna of Iran, a check list". Zootaxa. 4033 (2): 237–258. doi:10.11646/zootaxa.4033.2.3. PMID 26624401.
  11. ^ Gherman, Călin Mircea; Mihalca, Andrei Daniel (2017). "A synoptic overview of golden jackal parasites reveals high diversity of species". Parasites & Vectors. 10 (1): 419. doi:10.1186/s13071-017-2329-8. PMC 5603039. PMID 28915831.
  12. ^ Bolette, David P. (August 1997). "First Record of Pachysentis canicola (Acanthocephala: Oligacanthorhynchida) and the Occurrence of Mesocestoides sp. Tetrathyridia (Cestoidea: Cyclophyllidea) in the Western Diamondback Rattlesnake, Crotalus atrox (Serpentes: Viperidae)". The Journal of Parasitology. 83 (4): 751–752. doi:10.2307/3284256. JSTOR 3284256. PMID 9267421.
  13. ^ Carbajal-Márquez, Rubén Alonso; González-Solís, David; Cedeño-Vázquez, J. Rogelio (2018). "Endoparasites of Crotalus tzabcan (Serpentes: Viperidae), with a checklist in rattlesnakes". Journal of Parasitic Diseases. 42 (2): 303–314. doi:10.1007/s12639-018-1001-3. PMC 5962485. PMID 29844637.
  14. ^ Machado-Filho, 1950 Machado-Filho D.A. Revisão do gênero Prosthenorchis Travassos, 1915 (Acanthocephala). Memórias do Instituto Oswaldo Cruz. 1950; 48:495-545
  15. ^ Muniz-Pereira, Luís C.; Corrêa, Pilar; Bueno, Cecília; Vieira, Fabiano M. (2016). "Rediscovery of Pachysentis gethi (Acanthocephala: Oligacanthorhynchidae), a parasite of wild lesser grison Galictis cuja (Carnivora: Mustelidae) from Brazil". Revista Mexicana de Biodiversidad. 87 (4): 1356–1359. doi:10.1016/j.rmb.2016.10.010.

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