A. Wakefield 
A review of Marginella bicatenata 
profile, smooth, denticles absent, external varix strong 
with varix groove externally. Posterior notch absent, 
siphonal notch weak. Four strong pilications, first two 
oblique, third and fourth straighter, round crested, 
spacing between increasing from tirst to fourth, ends 
terminate at level of lip except for first which sweeps 
round to join with base of columella and anterior end 
of lip. 
Animal unknown. 
Etymology. The species is named after Alan 
Seccombe (Cape Town), who first drew the authors 
attention to this species. 
Remarks. The type sériés (Figs 27-36) displays the 
variability in this species. The number ol short axial 
dashes in the two bands varies slightly, from 19 to 23 
in the anterior band and from 19 to 24 in the posterior 
band. Whilst many shells are marked only with the 
two main spiral rows, others hâve extra rows ol tiner 
markings. Paratype 2 (Figs 33, 34) is exceptionally 
well marked and reveals these extra spiral lines of 
extremely fine dots and dashes on the body whorl, 
with 22 fine spiral dotted lines between the two main 
bands, but also several anteriorly, and posteriorly onto 
the spire. Paratype 1 (Figs 31,32) has these extra line 
spiral lines of dashes and dots more organised so they 
line up in an axial pattern. 
DISCUSSION 
Although the colour pattern of M seccombei 
apparently links it to the M. bicatenata complex, there 
are several characters which when studied in detail, 
provide us with an indication that M seccombei is not 
closely related to it at ail. Firstly, the shells of the M 
bicatenata complex are ail relatively thin and hâve 
lower W:L ratios; 54-60% (mean 56%) for M 
bicatenata and 52-54% (mean 53 % ) for M lemaitrei. 
The W:L ratio of M. seccombei is much higher at 58- 
66 % (mean 61.4%) and is clearly a more robust, 
stockier shell than those of the M bicatenata group. 
Secondly, the double row of reddish-brown axial 
dashes in M. seccombei , is fundamentally different in 
its genesis from the double row of smudged charcoal 
grey spots of the other species. This strongly suggests 
that M. seccombei has a different phyletic lineage, and 
that its pattern should be regarded merely as a 
convergent shell character with the M bicatenata 
group. "We must look elsewhere for links to its related 
species. 
When the species in the M. ornata complex express 
spiral lined patterns, they tend to do so as bands of 
small axially orientated markings. This is very évident 
on reddish specimens of M. ornata Redfield, 1870 and 
also in M. beltmani Fïart, 1993 and M. peelae 
Bozzetti, 1993. M seccombei also shares the same 
general morphology of the shells in the M. ornata 
complex, with their stocky outline and convex, often 
stepped later spire whorls. On purely conchological 
grounds therefore, a relationship with the M. ornata 
complex would seem justified although the lack of 
external lip markings in M seccombei , compared with 
strongly marked lips of those in the M ornata 
complex, cannot be ignored. 
Looking then to more northerly species for allies of M 
seccombei , the pattern and morphology of two deep- 
water Mozambique species M. verdascai Hayes & 
Rosado, 2007 and M. monicae Bozzetti, 1997 appear 
close. M verdascai , though much smaller at a length 
of 5.6 - 6.8 mm (in the type sériés), has a very fine 
spiral lined pattern very much like that seen in the 
better preserved specimens of M seccombei. 
Figures 1-38 
1-21. Marginella bicatenata , G.B. Sowerby (111), 1914; 
1-2. M. bicatenata , Holotype, 13x7 mm, Coll. Tomlin (NMW 1955.158.01434); 3-4. Off Durban, Natal,12.8 x 
6.9 mm, 29.825°S 31.2383°E (NM D3819); 5, 6. Off Durban, Natal, 13.9 x 7.5 mm, 30.0132°S 31.06°E (NM 
DI 159); 7, 8. Off Durban, Natal, 15.7 x 8.5 mm, 30.0067°S 31.05°E (NM DI 094); 9, 10. Off Durban, Natal, 
13.5 x 6.6 mm (NM E8656); 11,12. Off Durban, Natal, 11.7 x 6.8 mm, 30.0182°S 31.0533°E (NM, D800); 13- 
15. M tomlini , Holotype, trawled off Cape St. Blaize, Southern Cape, South Africa in 192m, 18x10 mm (SAM 
A3704); 16, 17. Southern Agulhas Bank, Southern Cape, South Africa, 16.2 x 9.33 mm (AWC); 18-22. Sériés 
demonstrating pattern and morphologie variability, data unknown (photo Lussi). 
22-26. Marginella lemaitrei Liltved & Millard, 1994; 
22-24. Holotype, Cape St. Blaize, Southern Cape, South Africa, 18.4 x 10.0 mm (SAM, A37572); 25, 26. Data 
unknown (photo Lussi) 
27-38. Marginella seccombei n.sp., off Durban, KwaZulu-Natal, dredged dead in 150m 
27-30. Holotype, 12.61 x 7.46 mm (NM, W8641/T2985); 31, 32. Paratype 1. 13.29 x 8.37 mm (NM, 
W8642/T2968); 33, 34. Paratype 2. 12.48 x 8.28 mm (AWC); 35, 36. Paratype 3. 10.88 x 6.35 mm (TMC); 37, 
38. Data unknown (photo Lussi). 
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