The Isopods of Abyssal Depths in the Atlantic Ocean

Synonyms: Dendrotioniidae Vanhoffen, 1914; —
Dendrotiini Nordenstam, 1933, pp. 198-199.
Diagnosis: Paraselloidea with free cephalon. All
peraeopods ambulatory. Mandibular incisor with
teeth, lacinia with teeth, molar expanded, truncated.
Maxillipedal palp with narrow subsimilar articles, all
less than one-half the width of endite. Uropods with
long peduncle, biramous.
Composition: This family contains Dendrotion G. O.
Sars, a shallow water genus, and the new abyssal genus
described herein. I have transferred Mormomunna
Vanhoffen and Pseudomunna Hansen to the Munnidae
(p. 172-173.)
A KEY TO THE GENERA OF THE
DENDROTIONIIDAE
1. Mandible with palp
1. Mandible without palp
DENDROMUNNA, new genus
ABYSSAL ATLANTIC ISOPODS 167
Family: DENDROTIONIIDAE
Dendrotion G. O. Sars
Dendromunna, n. gen.
Type species: Dendromunna spinipes, new species.
Diagnosis: Dendrotioniidae with one pleonal somite.
Mandible lacking palp. Coxal plates visible
in dorsal view on peraeonal somites 2-6 inclusive.
Lateral borders of peraeonal somites expanded into
spine-like processes, each process with an apical
cluster of spines. Dorsum of body with similar projections.
Uropoda biramous, rami shorter than
peduncle.
Composition: This genus contains only the type.
Dendromunna spinipes, new species
Figure 52 A-B
Synonyms: None.
Diagnosis: Dendromunna with a pair of stout
apically spinous spine-like processes on dorsum of
peraeonal somites 2-4 inclusive. Uropoda with rami
one-sixth the length of the stout peduncle. Eyes
Diagnosis: Paraselloidea with free head, eyes
lacking, mandibles normal, molar process well
developed, expanded at truncated apex. Antennae
shorter than body. First antenna much shorter than
second antenna. All peraeopods simple, last six
walking legs. Dactyls of last six peraeopods with two
claws. Pleon with one somite only. Uropoda uniramous
or biramous, peduncle present. Maxillipedal
palp with first three articles expanded, as wide as
Family: IANIRELLIDAE
Figure 52. A-B: Dendromunna spinipes, n. sp.
A: dorsal view female holotype; B: maxilliped.
C: lanirella lobata Richardson, dorsal
view intersex.
lacking. Frons of cephalon concave. Apex of pleon
convex and fringed with setae.
Measurements: Female holotype length 2.0 mm.,
width pleotelson 0.3 mm.
Type locality: South Atlantic, L.G.O. Biotrawl No.
54, type only, cat. no. 1-182.
Distribution: Known only from type locality.
Affinities: Unique.
endite. Anus contained in branchial chambers.
(Modified from Menzies, 1956a, p. 11.)
Composition: This family contains at least two
related genera, lanirella and Spinianirella, and possibly
Rhacura. The species lanirella pusilla type of lanirella
Sayce, being a homonym, deserved a new name, which
Richardson (1904, p. 6) suggested as Heterias. It does
not belong to lanirella Bonnier.