led to the availability of more specimens for study.
Schraml (2003) recently suggested that many of the speci-
mens entering the aquarium trade represent cryptic,
undescribed species. The aim of this study was to evalu-
ate the taxonomy of this group, bearing in mind that cryp-
tic species may exist. This possibility has led to the
utilization of several unconventional diagnostic charac-
ters, which have revealed undescribed species of
Synodontis from Lake Tanganyika.
 Phylogenetic relationships of the endemic species
of Synodontis in Lake Tanganyika have not been inten-
sively studied. Brichard (1978) suggested that the spe-
cies do not form a monophyletic group. However, the
unique pattern of rayed fin coloration and the presence
of vertical folds in the skin constitute two synapomorphies
supporting the monophyly of the endemic species of
Synodontis in Lake Tanganyika. It is possible that S.
melanostictus does not share a most recent common
ancestor with the Tanganyikan endemics, given its wider
distribution and differences from the endemic species in
its rayed fin coloration and lack of vertical folds on the
skin.

 METHODS AND TERMINOLOGY
Measurements were taken from the left side to the near-
est 0.1 mm using digital calipers and follow Poll (1971).
All counts were made using a Leica MZ75 dissecting
microscope. Vertebral and caudal-fin ray counts were
taken using lateral radiographs. Vertebral counts follow
the method of Skelton and White (1990), with the first
five fused vertebrae of the Weberian apparatus excluded
from reported values. Notation for fin ray counts is as
follows: upper case Roman numeral = fin spine, lower
case Roman numeral = unbranched rays, Arabic nu-
meral = branched fin rays. Terminology for premaxil-
lary dentition follows Skelton and White (1990). Gut
length measurements and observations of the hindgut
chamber of all species were performed only on speci-
mens that had a belly cut made prior to the beginning of
this study, with the exception of UF specimens, which
were dissected. The hindgut chamber corresponds to
the "poche intestinal" of Taverne and Aloulou-Triki
(1974). All photographs were taken using a Kodak
EasyShare CX7430 digital camera and edited using
Adobe Photoshop CS2. Maps were produced using
Adobe Illustrator. Institutional abbreviations follow
Leviton et al. (1985) except for that of the South Afri-
can Institute of Aquatic Biodiversity (SAIAB).

CHARACTERS EXAMINED
 In addition to the 22 morphometric measurements
and seven meristic counts that were made for all speci-


BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL. 46(4)

 mens, several new characters were found to be diag-
 nostically useful. This is in contrast to most of the work
 that has previously been done in this genus, which has
 tended to rely mainly on morphometric ratios to diag-
 nose species. These new characters are particularly
 appealing because they allow for easy and accurate vi-
 sual identification of specimens. Some of these charac-
 ters, such as fin spine color are self-explanatory. Oth-
 ers are explained below.
 Foremost among these characters is the axillary
 pore, an opening (or series of openings) that is located
 between the base of the pectoral fin spine and ventral
 margin of the humeral process (Figs. 2-5). The function
 of the axillary pore is unknown in mochokids, and the
 absence or presence of this structure has been noted in
 only one previously described species of Synodontis
 (Friel & Vigliotta 2006). The presence of a similar struc-
 ture has been noted in seven other catfish genera:
 Ariopsis (Ariidae) (Halstead et al., 1953), Ameiurus,
 Ictalurus, and Noturus (Ictaluridae) (Reed 1907;
 Birkhead 1967, 1972), Acrochordonichthys (Akysidae)
 (Ng & Ng 2001), Ituglanis (Trichomycteridae) (Datovo
 and Landim 2005), and is also present in Glyptothorax
 (Sisoridae) (pers. obs.). In Acrochordonichthys, this
 structure has been shown to produce a mucosal secre-
 tion that possesses toxic properties (Ng & Ng 2001).
 The utility of this secretion in the other genera has been
 a matter of some debate. The presence or absence of
 this character divides the 11 Tanganyikan species of
 Synodontis into two groups; six species have an axil-
 lary pore (Table 1) and five (including the non-endemic
 S. melanostictus) do not (Table 2).
 All species of Synodontis have a premaxillary
 toothpad, with several rows of unicuspid, chisel-shaped
 teeth. In some species this toothpad is continuous, while
 in others it is clearly composed of two elements, which
 are separated by a thin band of skin or a suture that


Figure 2. The axillary pore of Synodontis
multipunctatus, holotype, BMNH 1898.9.9.76,280 mm
TL, 220 mm SL.