Urnaloricus gadi nov. gen. et nov. sp. (Loricifera, Urnaloricidae nov. fam.), an aberrant Loricifera with a viviparous pedogenetic life cycle

• Published in: Journal of Morphology
• Main Authors: Heiner, Iben, Kristensen, Reinhardt Møbjerg
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2008
• Subjects: Faroe Bank; Faroe Islands; North Atlantic
• Online Access: http://dx.doi.org/10.1002/jmor.10671; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fjmor.10671; https://onlinelibrary.wiley.com/doi/pdf/10.1002/jmor.10671

Abstract A new species of Loricifera, Urnaloricus gadi nov. gen. et nov. sp., is described from the Faroe Bank, located Southwest of the Faroe Islands, North Atlantic. The new species does not fit into any known families of Loricifera and therefore it is grouped into a new family Urnaloricidae nov. fam. The new species is characterized by having a very complicated life cycle that involves a large cyst‐like mega‐larva, two reduced larval instars and the Higgins‐larvae eating their maternal stage from within. An adult stage is missing. This form of reproduction is called viviparous pedogenesis and normally is found only in nematodes and insects. In the life cycle of Urnaloricidae nov. fam., there are two types of free‐living larval stages: a Higgins‐larva and a mega‐larva. The latter is found in two different forms, a pre‐ and a cyst‐forming mega‐larva. Additionally, there are two reduced life history stages, the reduced larval stage (probably a postlarva) and the ghost‐larval stage inside the cyst‐forming mega‐larva. The external morphology of the two forms of mega‐larvae is much reduced, e.g., the introvert has only a few rows of scalids when compared with the Higgins‐larva. The pre mega‐larva is free‐living and can sometimes be covered with coccoliths. Internally, a large ovary with a few oocytes, a digestive system, and an internal armature with retracted scalids are present. The pre mega‐larva presumably molts into a cyst‐forming mega‐larva and thereby the ovary is now seen inside the cyst‐forming mega‐larva. The cyst‐forming mega‐larva has the same structures as in the pre mega‐larva though here the scalids are protruded and there is a gonopore. Inside the cyst‐forming mega‐larva the ovary produces more oocytes and begins to fill out the entire lumen. At this stage the cyst‐forming mega‐larva molts first to the presumed postlarval stage, and then this stage molts to a ghost‐larva. Hence, the ovary now matures inside the ghost‐larva, which is surrounded by both the cuticle of the reduced postlarval stage and ...