Notarius

Betancur-R, Ricardo & P, Arturo Acero, 2004, tus (Jordan and Gilbert) (Siluriformes: Ariidae) from the eastern Pacific, with evidence of monophyly and limits of Notarius, Zootaxa 703, pp. 1-20 : 17-18

Key to described species of the genus Notarius from the eastern Pacific

The species of the genus Notarius are distinguished from other EP ariid taxa by the following combination of features: humeral process pointed, triangular to elongated, but never fan­shaped; three pairs of barbels present; fleshy furrow between posterior nostrils absent; fleshy groove in median depression of head absent; coarse to sharp granules or spinulations on anterior surface of head shield absent; gill rakers on rear surfaces of first two gill arches absent. Some of the data ranges showed below are based on wider ranges proposed by Kailola and Bussing (1995).

1 Predorsal plate large, square or hexagonal and shaped like a forward pointing arrow .. .................................................................................................................... N. troschelii

­ Predorsal plate narrow and crescent­shaped ................................................................. 2

2 Gill rakers on second arch 5–6; anal fin rays 23–28 .............................. N. lentiginosus

­ Gill rakers on second arch 8 or more; anal fin rays 17–22 ........................................... 3

3 Epioccipital bones extensively invasive over skull surface, and forming with the supraoccipital a basally wide complex process which tapers drastically posteriorly ( Fig. 6 ); supraoccipital process length shorter than base of complex process width; maxillary barbels relatively long, their length in adult specimens 26.7–30.3% SL........ ................................................................................................................... N. insculptus

­ Epioccipital bones not invasive or only slightly invasive over skull surface ( Fig. 2 ); supraoccipital process length as long as or longer than its width at base; maxillary barbels relatively short, their length in adult specimens 26.1% SL or less....................... 4

4 Mouth small, its width 33.9–42.5% HL; anterior internarial distance 17.9–24.0% HL; eye relatively large, its diameter 3.5­4.5% SL ............................................................. 5

­ Mouth large, its width 44.1–54.2% HL; anterior internarial distance 25.3–32.2% HL; eye relatively small, its diameter 2.5­3.7% SL ............................................................. 6

5 Gill rakers on first arch 11–13; lips thin; mandibulary barbels comparatively short, their length 10.2–13.1% (mean 11.6%) SL; caudal peduncle relatively slender, its depth 6.1–6.7% (mean 6.4%) SL ........................................................................ N. biffi

­ Gill rakers on first arch 8–10; lips usually thick; mandibulary barbels comparatively long, their length 13.7–17.7% (mean 16.1%) SL; caudal peduncle relatively deep, its depth 6.8–7.4% (mean 7.1%) SL ........................................ N. planiceps / aff. planiceps

6 Supraoccipital process elongated, its base width 1.6–1.7 in its length ............ N. cookei

­ Supraoccipital process relatively wide and triangular­shaped, its base width 1.0– 1.3 in its length ....................................................................................................... N. kessleri

Figures

FIGURE 2. Dorsal view of head of a female paratype (UCR 2451 ­ 2, voucher 95 ­ 7; 72 mm HL) of Notarius biffi, from the Pacific coast of Costa Rica.

FIGURE 6. Head shield of a female specimen (STRI 5715, 16 mm supraoccipital process length) of Notarius insculptus. CP: complex process; E: epioccipital (= epiotic); S: supraoccipital.