Aiteng ater

Aiteng ater is a species of sea slug, a marine gastropod mollusk in the family Aitengidae.^[2]

The specific name ater is from Latin language and means black, in reference to the appearance of the slug on the mud.^[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, 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] Eyes are the only externally clearly visible feature on its head.

Aiteng ater has unusual combination of morphological characters:

• reduction of mantle cavity^[1]
• prepharyngeal (circumpharyngeal) nerve ring^[1]
• presence of ascus^[1] However re-examination of the doubtful "ascus" in Aiteng ater is necessary, because examination of 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.^[1]
• uniseriate radula (radula with a descending and ascending limb)^[1]
• the radula with a strong rhachidian tooth^[1]
• the large, internal lateral eyes closely associated with the cerebral ganglia^[1]
• the presence of a foot groove^[1]
• a branched digestive gland.^[1]

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^[1]
• it lacks presence of 1-2 head appendages (with characteristic innervation of the rhinophores)^[1]
• it lacks the ability to retract the head-foot complex into the visceral hump.^[1]

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 frontal part of the notum.^[1]

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.^[1][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 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,^[1] because the presence of spicules is confirmed for undescribed species Aitengidae sp. from Japan.^[1]

References

This article incorporates CC-BY-2.0 text from the reference.^[1]