Frable et al Description of a new species of Synodus in the western Atlantic Ocean 
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Key to the western Atlantic species of Synodus 
This key is modified from a provisional key for Synodontidae constructed by Russell (2003). 
la Scales in lateral line 43 to 52 2 
lb Scales in lateral line 54 to 65 4 
2a Dorsal fin with anterior rays extending to, or usually beyond, tips of succeeding rays 
when depressed; lower jaw ending in fleshy knob; no black scapular blotch on shoulder 
under gill cover Synodus poeyi 
2b Dorsal fin with anterior rays not extending beyond, but occasionally extending to, tips 
of succeeding rays when depressed; lower jaw rounded anteriorly, without fleshy knob; 
black scapular blotch present on shoulder under gill cover 3 
3a Caudal fin with 3-5 dark bars spanning both lobes; pored scales in lateral line 49-52; 
scapular blotch small and rectangular (length <12% HL); anterior-nostril flap broad and 
short, not tapering significantly posteriorly and not extending beyond posterior nostril 
when depressed Synodus intermedius 
3b Caudal fin without prominent dark bars but with dark pigment on lower lobe; pored 
scales in lateral line 45-48; scapular blotch large and ovoid (length >14% HL); anterior- 
nostril flap large, tapering posteriorly and extending beyond posterior nostril when 
depressed Synodus macrostigmus new sp. 
4a Three rows of complete scales between lateral line and base of dorsal fin Synodus saurus 
4b Four to 6 rows of complete scales between lateral line and base of dorsal fin 5 
5a Snout rounded and blunt, its length less than diameter of eye; anal-fin base much 
shorter than dorsal-fin base; tip of pectoral fin extending well beyond base of pelvic fin; 
dark spot present on tip of upper jaw; predorsal scales 15 to 18 Synodus synodus 
5b Snout triangular and pointed, its length greater than diameter of eye; anal-fin base 
slightly shorter to longer than dorsal-fin base; tip of pectoral fin falling short of or just 
reaching pelvic-fin base; no dark spot on tip of upper jaw; predorsal scales 20 to 30 6 
6a Anal-fin rays usually 10 or 11 (rarely 12); dorsal-fin base as long as or longer than anal-fin 
base; adipose lids around orbit thick; tip of snout sharply pointed; anterior-nostril flap 
narrow and tapering to filament distally; species currently known from off Central and 
South America, Jamaica and Haiti Synodus bondi 
6b Anal-fin rays usually 12 or 13 (rarely 11); dorsal-fin base usually shorter than anal-fin 
base (rarely same length); adipose lids around orbit narrow; tip of snout not sharply 
pointed, slightly rounded; anterior-nostril flap broad and triangular, not tapering to 
filament; species currently known from New York south to the Leeward Islands, the 
Gulf of Mexico, and Belize Synodus foetens 
are unknown. Kottelat (1988) did find a specimen at 
MHNN collected off Brazil about the same time as 
Spix and Agassiz’s ( 1829) Saurus longirostris (MHNN 
793), which may be a syntype. However, as noted by 
Kottelat (1988), the length of that specimen does not 
match the lengths of S. longirostris recorded in the 
original description or in Agassiz’s notes. Although 
this specimen could be the same one described by 
Fowler (1939) as S. bondi on the basis of its pointed 
snout, short anal Fin, and collection locality (as noted 
previously, S. bondi is also known from Brazil), it 
would be imprudent to resurrect this name based on 
a specimen that may or may not be a primary type. 
Finally, we examined the holotype of another syn- 
onym, Saurus spixianus Poey, 1860 (MCZ 6884) and 
found that it has 13 anal-fin rays, a rounded snout, 
and morphometries similar to those of S. foetens. Our 
observations, therefore, corroborate the synonymy of 
Saurus spixianus with S. foetens. 
Discussion 
Molecular variation 
Our DNA barcoding analysis of Synodontidae in the At- 
lantic (Fig. 1) revealed 13 highly divergent lineages (av- 
erage divergence in COI among lineages: 20.2%, range: 
9.0-30.7%). Morphological examination of voucher 
specimens indicated that 10 of the lineages correspond 
to the following previously described species: Saurida 
brasiliensis, S. caribbaea (Smallscale Lizardfish), S. 
normani (Shortjaw Lizardfish), S. suspicio (Suspicious 
Lizardfish), Synodus foetens, S. intermedius, S. poeyi, S. 
saurus, S. synodus, and Trachinocephalus myops. Of the 
additional 3 lineages, 2 represent morphologically dis- 
tinct species originally identified as S. intermedius and 
S. foetens. We describe S. macrostigmus for the former 
and resurrect S. bondi for the latter. The thirteenth 
lineage in the data set represents specimens from deep 
