Family Leptolaimidae

Revised 06/05/24

Chromadorea

Chromadoria

Plectida

Plectina

Leptolaimoidea

Leptolaimidae Orley, 1880

Type genus of the family: Leptolaimus de Man, 1876

Synonyms per Holovachov and Bostrom, 2015:

Halaphanolaimidae De Coninck & Schuurmans Stekhoven, 1933

Peresianidae Vitiello & De Coninck 1968

As of 2021, the family includes seven genera, five of which inhabit marine and brackish habitats (Holovachov & Boström, 2004). Of these genera, Leptolaimus de Man, 1876  inhabits marine or brackish habits and includes over 70 nominal species,several of which are considered invalid (Gharahkhani et al;., 2021).

There were three subfamilies: Anonchinae, Camacolaiminae and Leptolaiminae (Hope and Tchseunov, 1999).. Of these, Camacolaiminae has been elevated to the rank of family (Camacolaimidae) (Holovachov and Bostrom, 2004).

General Characteristics:

• Cuticle finely  to  coarsely striated., with opr without narrow lateral alae
•  Head with six  inner and six  outer  labial  papilliform  sensilla  and  four  cephalic  setiform  sensilla,  all  in  separate  circles.
•  Amphid a modified unispiral, with  circular  to  oval  aperture  usually  situated  anterior to, level with cephalic sensilla.
•  Ocelli present or  absent. 
• Soatic pore (alveolar) sensilla present
• Armament of  buccal  capsule  usually  present,  either as  an  onchiostyle,  free­standing  onchium,  or  tooth-like  projections  of cheilostome  (odontia). 
• Esophagus  either clavate with strongly to  weakly developed musculature with slight glandular swelling of dorsal sector  at  posterior  end,  often  with  lumen  displaced  slightly  ventrad;  or  esophagus  with  elongated  glandular  posterior  region  devoid  of musculature  and  with  narrow  anterior  isthmus  conveying  gland  duct to  base  of onchiostyle. 
• Ventral  gland situated  completely  posterior  to  esophagus; excretory pore usually not evident. 
• Several  single­celled  glands  with  elongated  neck  present  in  body  cavity,
• Tail  uniformly  conical to  acute, with terminal  spinneret. 
• Females didelphic, amphidelphic with ovaries reflexed; each ovary  with two lateral sac-like spermathecae
• Males  diorchic,  testes  anteriorly  directed or opposed. 
• Ventromedian supplements  alveolar,  tuboid,  or  absent.  Ventromedian, alveolar supplements  sometimes  present  in  anterior  body  (cervical) region. 
• Spicules paired; proximal ends of spicula usually bent sharply ventrad. 
• Gubernaculum present
• Male tail with one to  three  ventromedian sensilla. 

Ref: Hope and Tchseunov, 1999; Holovachov and Bostrom, 2004

References

Gharahkhani, A., E. Pourjam, O. Holovachov, M. Pedram. 2021. Phylogenetic relationships of Leptolaimus de Man, 1876 (Plectida: Leptolaimidae) with description of two new species from the Persian Gulf, Iran. Nematology 23:153-169.

Holovachov, O. and Bostrom, S. 2004. Morphology and systematics of the superfamilies Leptolaimoidea Örley, 1880 and Camacolaimoidea Micoletzky, 1924 (Nematoda: Plectida).  J. Nematode Morphology and Systematics 7:1-49.

Hope, W.D. and Tchesunov, A.V. 1999. Smithsoninema inaequale n.g,  and n.sp. (Nematoda, Leptolaimidae) inhabiting the test of a foraminiferan. Invertebrate Biology  118: 95­108.

Urkmez, D. and Brennan, M.L. 2013. A new species of Halaphanolaimus (Nematoda: Leptolaimidae) from the southern Black Sea (Turkey) with a modified key for species identification. Zootaxa 3691:220-228.

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