The Isopods of Abyssal Depths in the Atlantic Ocean

Diagnosis: Munnidae with eyes. Body covered
densely with stout spines. Mandibular palp present,
Goxal plates visible in dorsal view on peraeonal
somites 2-7. Endite of second male pleopod curved,
appendage pointed and hirsute. Lateral expansion
lacking from apex of male first pieopods. First peraeopod
stout, dactyl with two claws, other articles with
many stout setae on inferior margin. Uropoda
massive, with peduncle and biramous and dorsal
insertion.
Composition; The dorsal insertion of the massive
uropods characterizes this genus, and it is therefore
highly probable that Mormomunna Vanhoffen and
Pseudomunna Hansen are synonyms. Hansen did not
think so on the basis of the male first pieopods, but
even within Munna the male first pieopods differ
rather markedly. In the species which I have been
able to examine I did not find the maxillipedal palp
articles as narrow as indicated by Hansen for hystrix;
ABYSSAL ATLANTIC ISOPODS 175
they are nevertheless narrower than other Munnidae.
The species range from bathyal to abyssal depths.
LIST OF THE SPECIES OF ACANTHOMUNNA
Depth Range (Meters)
Species Least Greatest
1. proteus
2. spinipes
3. hystrix
A KEY TO THE SPECIES OF
ACANTHOMUNNA
1281 2011
385 385
1505 1505
I. Cephalon with spines on dorsum 2
1. Cephalon without spines on dorsum 3
2. With a central cluster of three spines . beddardi, n. sp.
2. With one spine near each lateral
border proteus Beddard
3. First peraeonal somite with only four
spines spinipes (Vanhoffen)
3. First peraeonal somite with more than
six spines hystrix (Hansen)
Figure 58. Notoxenoides abyssi, n. sp. A: dorsal view male holotype; B: gnathopod; C:
maxilliped; D: uropod; E: mandible; F: first pleopod; G: third pleopod.