Aiteng ater

Aiteng ater is a species of sea slug, a marine gastropod mollusc in the family Aitengidae.^[2] The specific name ater is from the Latin language and means black, in reference to the appearance of the slug on the mud.^[2]

Aiteng ater
Scientific classification
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Gastropoda
Family:	Aitengidae
Genus:	Aiteng
Species:	A. ater
Binomial name
Aiteng ater Swennen & Buatip, 2009[1][2]

Aiteng ater was chosen by the International Institute for Species Exploration of Arizona State University to be one of the "Top 10 New Species described in 2009".^[3]

Distribution

The distribution of Aiteng ater includes Thailand. The type locality is 8°29'18" N, 100°10'55" E, Amphoe Pak Phanang, Pak Phanang Bay, in the Gulf of Thailand.^[2]

Description

The size of the body is 8–12 mm.^[2] The shape of the body is elongate, but broad.^[2] The color of the slug is from grey to black.^[2] The eyes are the only externally clearly visible feature on its head.

Aiteng ater has an unusual combination of morphological characters:

• Reduction of mantle cavity^[4]
• Prepharyngeal (circumpharyngeal) nerve ring^[4]
• The presence of ascus^[4] However, re-examination of the supposed "ascus" in Aiteng ater is necessary, because an examination of an undescribed species Aitengidae sp. from Japan showed no true (i.e. sacoglossan-like) ascus containing old teeth, just a radula slightly bent at the end.^[4]
• Uniseriate radula (radula with a descending and ascending limb)^[4]
• The radula has a strong rhachidian tooth^[4]
• The large, internal lateral eyes closely associated with the cerebral ganglia^[4]
• The presence of a foot groove^[4]
• A branched digestive gland.^[4]

This species lacks several acochlidian characteristics:

• It has no shell^[2]
• No tentacles^[2]
• No gills^[2]
• No cerata^[2]
• It lacks the division of the body into head-foot complex and visceral hump^[4]
• It lacks presence of 1–2 head appendages (with characteristic innervation of the rhinophores)^[4]
• Tt lacks the ability to retract the head-foot complex into the visceral hump.^[4]

Aiteng ater has a notum with a free margin.^[2] However, in the absence of a separated visceral hump, Aiteng ater is able to retract its head under the frontal part of the notum.^[4]

Ecology

Aiteng ater is an amphibious species which lives in mangrove forests in the intertidal zone, on the mud.^[2] It lives "amphibiously", and tolerates marine to brackish waters, but there are no observations of these animals truly leaving the water.^[4][2]

Aiteng ater feeds on insects, (is insectivorous).^[2] In the laboratory it has been observed to eat pupae of beetles (Coleoptera), pupae of Lepidoptera, imagos of mosquitos and larvae of ants.^[2]

Inside the bodies of individuals of Aiteng ater, there were found to be white elongated endoparasites; these are as yet unstudied.^[2] However the "parasites" described for Aiteng ater might represent spicules instead,^[4] because the presence of spicules is confirmed for the undescribed species Aitengidae sp. from Japan.^[4]