Records of the Western Australian Museum 18: 277-310 (1997). 
Two new cuttlefishes (Cephalopoda: Sepiidae) from the North West Shelf, 
and a redescription of Sepia sulcata Hoyle, 1885 
Chung Cheng Lu' and Amanda Reid 2 
1 Department of Invertebrate Zoology, Museum of Victoria, Melbourne, Victoria 3000, Australia 
2 140 Napoleon Street, Eltham, Victoria 3095, Australia (address for correspondence). 
Abstract - Two new cuttlefishes (Cephalopoda : Sepiidae), Sepia plana sp. 
nov. and Sepia senta sp. nov., are described, and a third species. Sepia sulcata 
Hoyle, 1885, is redescribed from the type and new' Australian material. The 
three species are found in the Indian Ocean off northwestern Australia at 
depths between 505-150 m. Sepia plana is found in the deeper end of this 
range, between 505-396 m. Sepia senta and Sepia sulcata have been collected 
at 426-256 m, and 404-150 m respectively. Sepia sulcata Hoyle was known 
previously from a single male collected off the Ki Islands in the Arafura Sea. 
INTRODUCTION 
The genus Sepia includes approximately 100 
species (Khromov et al. in press), and is the largest 
of three genera within the family Sepiidae. In the 
genus Sepia, 26 species are found in Australian 
waters, and 21 are endemic to this country (Lu in 
press, a). 
As part of a broader study to revise the cuttlefish 
fauna of Australia, two new species from the North 
West Shelf, Sepia plana sp. nov., and Sepia senta sp. 
nov. are described in this paper. In addition, Sepia 
sulcata Hoyle, 1885 is redescribed based on new 
material from the North West Shelf. The latter 
species was known previously only from a single 
male specimen collected off the Ki Islands in the 
Arafura Sea in 1874, and described later by Hoyle 
(1885). Khromov et al. (in press) has described its 
status as "probably valid, but insufficiently 
described". Conspecificity of the Australian 
animals with S. sulcata was confirmed by 
comparison with the type specimen. While the 
type, an immature male, differs from the more 
mature Australian males in the degree of 
modification of the hectocotylus, most other traits 
agree between the North West Shelf specimens and 
S. sulcata. 
This finding confirms the status of S. sulcata as 
valid and extends the distribution of the species to 
include northwestern Australia. The redescription 
of this species from the type and additional 
material provides information which previously 
was not known on females and mature males of 
this species. 
MATERIALS AND METHODS 
This study is based on specimens held in various 
museums. All material studied is listed in the 
Material Examined sections given with each species 
description. Institutional acronyms used 
throughout file paper are: BMNH - The Natural 
History Museum, London, United Kingdom; 
CSIRO - Commonwealth Scientific and Industrial 
Research Organisation, Australia; MV - Museum 
of Victoria, Melbourne, Australia and WAM - 
Western Australian Museum, Perth, Australia. 
Other abbreviations: coll. - collected, E - east, fms 
- fathoms, F - female, FV - Fisheries Vessel, Is. - 
Island, J - juvenile, m - metres, M - male, mm - 
millimetres, N - north, NW - northwest, NNW - 
north northwest, RV - research vessel, S - south, 
W - west, WNW - west northwest. 
Measurements and indices used throughout this 
paper are primarily those given in Roper and Voss 
(1983), using dorsal mantle length (ML) as a size 
standard. Some additional measurements are used, 
and these with the definitions listed by Roper and 
Voss (1983) are given in Table 1. Parts of the club 
and arm sucker rims are described using the 
terminology of Nixon and Dilly (1977), and 
nomenclature for radulae follows Nixon (1995). 
Beaks were described following Clarke (1986). 
Diagrammatic illustrations of measurements and 
terminology used for particular structures are 
shown in Figure 1. With respect to the arrangement 
of arm and club suckers, the term 'row' refers to 
suckers positioned perpendicular to the 
longitudinal axis of the arm or club. 'Series' refer 
to those positioned parallel to the longitundinal 
axis of the arm or club. 
Measurements were made either using dial 
callipers, or an eyepiece micrometer attached to a 
stereo microscope and (where possible) are given 
for 10 preserved specimens of each sex for each 
