100 
At the time Nukta was erected only S. heterorhynchos was known 
and a direct comparison between it and T. nukta was logical. The 
discovery of additional species with the oro-labial specialisations of 
S. heterorhynchos complicates the issue. Hora’s phyletic association 
focused on the remarkably modified snout found in each species but 
the discovery of species of Schismatorhynchos with unmodified 
snouts renders the association untenable because either the new 
Schismatorhynchos species would have had to regress to an unmodi- 
fied snout condition from the modified condition of S. heterorhynchos 
and TZ. nukta or T. nukta would have had to regress to an unspecialised 
oro-labial condition from the specialised condition of Schismato- 
rhynchos. Either possibility is more complex, and therefore deemed 
less likely, than the explanation required when justS. heterorhynchos 
and T: nukta were known. 
Hora, in making the comparison between S. heterorhynchos and 
T. nukta, was, in part, acting on the suggestion by Weber & de 
Beaufort (1916) that Schismatorhynchos might also be present on 
the Indian subcontinent, though they presented no evidence to 
support this suggestion. Hora’s comprehensive knowledge of the 
Indian fish fauna led him to conclude that the only species Weber & 
de Beaufort could possibly have been referring to was 7: nukta. 
However, they may have been simply following Bleeker (1853, 
1855), who noted in his description of S$. heterorhynchos that two 
Indian species illustrated in Gray (1830, 1832) appeared to have 
snouts similar in structure to the species he was describing. Bleeker 
listed Cyprinus gotyla Gray, 1830 (=Garra gotyla) and Cyprinus 
falcata Gray, 1832 (= ?Tylognathus falcatus; not Tylognathus 
diplostomus (Heckel, 1838) nor T: dycocheilus (McClelland, 1839)). 
The conclusion by Hora (1942:11) that Weber & de Beaufort could 
only have been referring to 7? nukta may well have been mistaken, 
and may have led to a comparison they, nor Bleeker, ever intended. 
The discovery of two additional labeonin species with oro-labial 
morphology like that of S. heterorhynchos demonstrates T. nukta is 
not the closest relative of S. heterorhynchos. This and Bleeker’s 
reference to the snout of species other than 7: nukta brings the 
character of a divided snout into sharp focus. 
A heavily tuberculate snout commonly occurs among labeonins, 
as does the separation of the ethmoidal region from the premaxil- 
lary—maxillary region by creases, folds, and indentations in the skin. 
In some cases these are deep enough to ‘divide’ the snout. Since the 
condition occurs widely, and sporadically among labeonins its status 
as a synapomorphy in any particular case must be confirmed by 
congruence with other characters. In the case of S$. heterorhynchos 
and T. nukta the requirement of corroboration from additional 
characters is not met. Rather, the oro-labial specialisations common 
to all species of Schismatorhynchos suggest any resemblance between 
the divided snout of S. heterorhynchos and T. nukta is one of 
convergence, and therefore without taxonomic significance. 
In summary, we support Reid’s exclusion of Nukta from 
Schismatorhynchos for three reasons: the oro-labial specialisations 
of Schismatorhynchos are unique among cyprinids; the ‘divided’ 
snout of S. heterorhynchos and T. nukta is not corroborated as a 
useful indicator of relationship; and Hora was probably mistaken 
when he assumed Bleeker and Weber & de Beaufort were suggesting 
a comparison between S. heterorhynchos and T. nukta. Subordinat- 
ing Nukta within Schismatorhynchos renders Schismatorhynchos 
polyphyletic. Restricting Schismatorhynchos to Bleeker’s and We- 
ber & de Beaufort’s concept of a group of labeonins with an elongate 
lower jaw cutting edge which separates the upper lip from the lower 
lips at the corner of the mouth, and also with a lower labial frenulum 
which houses the mandubular laterosensory canal, exactly matches 
Hora’s concept (1942:12—13) for the nominate subgenus Schismato- 
rhynchos. 
D.J. SIEBERT AND A.H. TIAKRAWIDJAJA 
SPECIES ACCOUNTS 
An account of each species of Schismatorhynchos is presented 
below, and a comparative account for all three is given at the end of 
the section. 
Key to the species of Schismatorhynchos. 
la. Snout with horizontal cleft, dark lateral band extends to the distal tips of 
muddiercatidaltim=nay's---eeeracs eens cease eee S. heterorhynchos 
1b. Snout without horizontal cleft, middle caudal fin-rays not pigmented 
sncdurneventavefondenied toeeinvcasecursnaetaneersetuctesertrdstrcet nes tence =n eee Go to 2 
2a. Dorsal fin branched ray count > 9 ................. S. endecarhapis sp. nov. 
2b. Dorsal fin branched ray count < 10............. S. holorhynchos sp. nov. 
Schismatorhynchos heterorhynchos (Bleeker, 1853) 
(Figs 1A,2,3A,5) 
Lobocheilos heterorhynchos Bleeker, 1853: 524. 
Schismatorhynchos lobocheiloides Bleeker, 1855: 259. 
Schismatorhynchus heterorhynchus Bleeker, 1863: 193. 
Tylognathus heterorhynchos Gunther, 1867: 67. 
SYNTYPE. BMNH 1866.5.2.82 (143.3 mm Sl), [Indonesia], 
Sumatra, Solok, H.C. Schwanenfeld. 
NON-TYPE MATERIALS. Sumatra—ZMA 115.911 (5, 175-228 mm 
S]); [Indonesia]; Sumatra, Penetai, E. Jacobson, VII-1915. MZB 
4818 (2, 119.6-156.6 mm Sl); Indonesia; Sumatra, Jambi Province; 
Batang Hari basin, Sungai Meringin at Muaraimat; col. Suroto and 
M. Siluba; 16-VIII-1982. 
Borneo (Kapuas River basin, Kalimantan Barat, Indonesia) — 
MZB 5456 (2; 67.9-71.2 mm SI), Sungai Kapuas at Putussibau, col. 
Munandar, 26-IV-1983. Upper part of Sungai Sibau, col. Ike 
Ratchmatica and Haryono, 25 June—7 July 1996: 1) MZB 8600, 
Station IV (1, 98.8 mm S1); 2) MZB 8601, Station IV, Habitat 2 (1, 
110.4 mm S1); 3) MZB 8602, Station VI.2 (2, 86.9-97.6 mm Sl); 4) 
MZB 8603, Station IX, at Muara Suluk (1, 134.0 mm SI); 5) MZB 
8604, Station XIII (5, 85.4-93.8 mm S]); and 6) MZB 8605, Station 
XIV, at Muara Apeang (1, 101.7 mm Sl). Sungai Putan, an upper 
basin tributary of Sungai Sibau; col. Ike Ratchmatica and Haryono; 
22-26 Jun 1996: 1) MZB 8606, Station III (2, 91.7—93.3 mm SI); 2) 
MZB 8607, Station IV (1, 106.6 mm S]); 3) MZB 8608, Station V (1, 
107.3 mm SI); 4) MZB 869, Station VIII (2, 89.4-96.0 mm S]); and 
5) MZB 8610, Station VI (1; 92.2 mm S1). Sungai Apeang, an upper 
basin tributary of Sungai Sibau; col. Ike Ratchmatica and Haryono; 
30 Jun 1996: 1) MZB 8611, Station X.2 (2, 98.6—128.2 mm Sl); and 
2) MZB 8612, Station X.4 (2, 104.8-136.9 mm SI). SungaiAring, an 
upper basin tributray of Sungai Sibau; col. Ike Ratchmatica and 
Haryono; 7 Jul 1996: 1) MZB 8613, Station XVI (1, 96.2 mm Sl); 
and 2) MZB 8614, Station XVI.2 (3, 97.2-131.0 mm Sl). Sungai 
Menjakan, an upper basin tributary of Sungai Sibau; col. Ike 
Ratchmatica and Haryono, | Jul 1996: 1) MZB 8615, Station XI.1 
(1, 132.6 mm SI); and 2) MZB 8616, Station X1.3 (1, 81.4 mm Sl). 
Sungai Sekedam Besar, an upper basin triburaty of Sungai Sibau: 
col. Ike Ratchmatica and Haryono; 25 June 1996, MZB 8617, 
Station II (3, 09.1-97.6 mm Sl). Sungai Berarap, an upper basin 
tributary of Sungai Sibau; col. Ike Ratchmatica and Haryono; 3 Jul 
1996; MZB 8618, (1, 95.0 mm Sl). 
DIAGNOSIS. A species of Schismatorhynchos with a deep horizon- 
tal cleft in snout (S. holorhynchos and S. endecarhapis without cleft 
in snout); snout, including cleft, heavily tuberculate, tubercles pyra- 
