Remipedia: Species

J.K. Lowry & M. Yerman

Division of Invertebrate Zoology
The Australian Museum
6 College Street, Sydney, NSW 2010, Australia
Email: jimlowry@crustacea.net

Introduction

In studies of remipedes to date the articles of the mouthparts are always referred to by segment numbers. This makes comparisons within remipede taxa and with other kinds of crustaceans difficult.

In this paper the maxillule, maxilla and maxilliped are based on a presumed seven articulate limb. There appears to be no evidence for a limb with 8 articles. This study also assumes that fusion in the first three to four articles may occur and that the propodus may be variously subdivided so that the limb can lengthen, but still remain flexible. This could be a distinct advantage in these predatory animals where the limbs are used for grasping. In Pleomothra something completely different is happening in the maxillule.

Maxillulle (maxilla 1). Simple in all taxa except Plemothra where it is carpochelate. This limb appears to be conservative in the remipedes and always has seven articles, except in Plemothra where article 1 (coxa) appears to be missing or not illustrated. The first three articles (coxa, basis and ischium) are free and each one has an endite. The fourth article (merus) may or may not have an endite. In Pleomothra article 5 (carpus) has a posterodistal projection which forms an opposing digit to the propodus and dactylus. Article 5 goes from slightly expanded in Speleonectes ondinae to greatly expanded in Godzillus.

Maxilla (maxilla 2). In all genera the first three articles (coxa, basis and ischium) are fused, but the three endites remain. There are various numbers of articles between article 5 (carpus) and the last articles which might be considered the dactylus. In Godzillus there is only one article which might be considered the propodus, but the number of subdivisions can vary from one to three. It could be argued that these are grasping limbs and in order to lengthen them and still maintain flexibility the propodus is subdivided. In Pleomothra and in Godzilliognomus the propodus forms 2 subarticles. In Cryptocorynetes and Speleonectes the propodus forms three sub-articles, in Lasionectes the propodus is divides into four sub-articles.

Maxilliped. In Pleomothra articles 2 and 3 (basis and ischium) are fused. The endites on all three articles are vestigial. Apparently the propodus is divided into two subarticles.

In Cryptocorynetes, Godzillus, Lasionectes and Speleonectes the first three articles (coxa, basis and ischium) are fused and the endites are absent. In Godzilliognomus and Pleomothra the propodus is apparently divided into two subarticles; in Godzillus the propodus is apparently divided into three subarticles; in Lasionectes and Speleonectes the propodus is apparently divided into four subarticles;

In Godzillognomus articles 1 to 4 (coxa, basis, ischium and merus) are fused. The remnant of what appear to be basal, ischial and meral endites remain. Apparently the propodus is divided into two subarticles.

So we would argue that these limbs are basically seven articulate. That in the maxillule all seven articles are present. In the maxilla and the maxilliped the first three articles (coxa, basis and ischium) and rarely the first four (merus) are fused, but the endites remain. The carpus (article 5) is expanded and the propodus (article 6) may be entire or subdivided, probably to give it more flexibility for catching prey. The dactylus is always small.

The structure of the musculature needs to be studied in order to verify these conclusions, but the maxillule seems to be conservative throughout the group and it has seven articles. Also the proximal articles, up to article 5 (carpus), all appear to be identifiable and so does the dactylus. So that leaves only the propodus to subdivide which it appears to do a number of times.

There are now 12 specis of remipedes known mainly form anchialine caves in the Atlantic Ocean, but also from norht-western Australia.

Monographs Monograph and Interactive Keys Interactive Key

Remipedia: Species

Monograph Interactive Key

aplectocheles, Pleomothra

Monograph Interactive Key (not available)

benjamini, Speleonectes

Monograph Interactive Key (not available)

entrichoma, Lasionectes

Monograph Interactive Key (not available)

epilimnius, Speleonectes

Monograph Interactive Key (not available)

exleyi, Lasionectes

Monograph Interactive Key (not available)

frondosus, Godzilliognomus

Monograph Interactive Key (not available)

gironensis, Speleonectes

Monograph Interactive Key (not available)

haptodiscus, Cryptocorynectes

Monograph Interactive Key (not available)

lucayensis, Speleonectes

Monograph Interactive Key (not available)

ondinae, Speleonectes

Monograph Interactive Key (not available)

robustus, Godzillius

Monograph Interactive Key (not available)

tulumensis, Speleonectes

Monograph Interactive Key (not available)

Cite this publication as: Lowry, J.K. & M. Yerman (2002 onwards). 'Remipedia: Species.' Version: 2 October 2000. http://crustacea.net/.