The J. L. B. SMITH INSTITUTE OF ICHTHYOLOGY SPECIAL PUBLICATION No. ro EVOLUTIONARY SIGNIFICANCE OF HOLAPOGON, A NEW GENUS OF CARDINAL FISHES (APOGONIDAE), WITH A REDESCRIPTION OF ITS TYPE-SPECIES, APOGON MAXIMUS BY Thomas H. Fraser RHODES UNIVERSITY GRAHAMSTOWN, SOUTH AFRICA 24 April 1973 ACKNOWLEDGEMENTS For co-operation during a brief visit to the British Museum (BMNH) I thank A. C. Wheeler, N. B. Marshall and P. J. P.Whitehead. A. C. Wheeler expedited loans of several specimens and G. Palmer helped to clarify an historical problem relating to which specimens represented the syntypes. Tornio Iwamoto provided information concerning the type of Apogonichthys landoni and specimens of Apogon magnifica at the California Academy of Sciences. Han Nijssen provided information on the maximum size of some species of Glossamia in the collections at the Zoologisch Museum, Amsterdam. I thank Ernest A. Lachner and M. M. Smith for critically reading the manu­ script. Funds for the study of fishes, travel grants and publishing this paper are provided by the South African Council for Scientific and Industrial Research and Rhodes University. EVOLUTIONARY SIGNIFICANCE OF HOLAPOGON, A NEW GENUS OF CARDINAL FISHES (APOGONIDAE), WITH A REDESCRIPTION OF ITS TYPE-SPECIES, APOGON MAXIMUS by THOMAS H. FRASER Senior Lecturer J. L. B. Smith Institute of Ichthyology Rhodes University, Grahamstown ABSTRACT A new genus is erected for Apogon maximus, a deep water cardinal fish occurring off the coast of southern Arabia in the Indian Ocean. Ho[apogon is a primitive genus near the ancestor which gave rise to all the living Apogoninae. The type-species, Apogon maximus Boulenger, 1887, is redescribed and aspects of its anatomy are investigated. INTRODUCTION In r887 Boulenger based a new species, Apogon maximus, on three large specimens from the Persian Gulf but did not give a figure. Day (r888: 784) synonymized Apogon maximus with A. b!fasciatus Ri.ippell. On the basis of three additional specimens Boulenger (1889 : 244) stated that Apogon maximus was "perfectly distinct from A. bifasciatus". He noted a number of valid differences but introduced some confusion (typographical error) as to the number of branched anal rays in A . maximus. Zugmayer (1913: 10) listed A. maximus from Oman without comment. Fowler and Bean (1930: 33), however, listed A. maximus as a synonym of A. taeniatus Ehrenberg, a senior synonym of A . bifasciatus Ri.ippell. Briefly reporting on one specimen from the Soutl1 Arabian coast, Norman (1939: 59) suggested that A . maximus was not conspecific witl1 A . taeniatus (=A. b!fasciatus). Boulenger's description, while adequate for some characters, is lacking and/or erroneous for other characters. An illustration of tl1e species is presented for the first time. Apogon maximus is important to concepts of evolution in the subfamily Apogoninae and the large genus Apogon. I METHODS Counts and measurements were made according to Hubbs and Lagler (1958). Measurements were made with dial calipers. Last dorsal and anal rays split to their bases are cotmted as one element each. The gillraker at the angle is included in the count for the lower arch. HOLAPOGON NEW GENUS Type species: Apogon maximus Boulenger, 1887: 655. DIAGNOSIS. Holapogon is monotypic. The diagnostic characters are given under the species account. Holapogon maximus (Boulenger, 1887) DIAGNOSIS. Eight first dorsal spines, the eighth reduced, usually hidden; seven soft anal rays; large supramaxilla; villiform teeth on premaxilla, dentary, vo~ner and palatine, none on ectopterygoid; preopercular ridge smooth, ventral and posterior edges serrated; infraorbital edges smooth except for one or two spines on the second bone; one spine on posttemporal; lateral line complete, scales ctenoid; three predorsals; two pairs of uroneurals. DESCRIPTION. For general body shape see figurer. Range of proportions (as a percentage ofstandard lengths): body depth 37-39%; head length 42-44%; eye length II-13%, snout length 9-u%; bony interorbital width 8-9%; upper jaw length 17-19%; caudal peduncle depth 15-16%; caudal peduncle length 19-20%; first dorsal spine length 4- 5%; second dorsal spine length 10-15%; third dorsal spine length 17-20%, fourth dorsal spine length 16-18%; first anal spine length 3%; second anal spine length 12-14%; pectoral fm length 26-28%; pelvic fm length 24-28%. Meristic counts and ranges for specimens examined: dorsal fm VIII-!,9; anal fin II,7; pectoral fin 13 or 14; pelvic fm !,5; principal caudal fin rays 9+8; well-developed gillrakers 15-17 (3-4+ 12-13), including rudiments 21-24 (2-4+3-4; 12-13+2-4); pored lateral-line scales 23-25; longi­ tudinal scale row above lateral line 24-25; transverse scale rows above lateral line 2; transverse scale rows below lateral line 6; median predorsal scales 5; circumpeduncular scale rows 10-II (5+2+5-6). SWIMBLADDER. Oval on dorsal side near anterior end; about 40 retial complexes in a pattern similar to some species of Cheilodipterus. CoLOURATION. Life colours unknown, but probably red with black spots. Juvenile with a some­ what different pattern from adult (fig. 1). Intestine and stomach pale and peritoneum silvery without black spotting. OSTEOLOGY. Caudal skeleton1 -Five hypurals, a parhypural, three epurals, two pairs of uroneurals, two autogenous haemal spines and secondary caudal rays not spinous. 1 P. H. Greenwood brought my attention to an error in designating the last three centra as pre-ural centra one and two and ural centrum one in a previous publication (1971) on Dinolestes. These should have been labelled pre-ural centra two and three and a composite, probably consisting of pre-ural centrum one and ural centrum one. In 1972 I used the term "terminal centrum" for this composite centrum and retained the erroneously numbered pre-ural centra. 2 FIGURE 1. Holapogotl tnaximus, lateral views of a juvenile (A) 82 mm SL, BMNH 1939·5.24.848, and an adult (B), 198 mm SL, BMNH 1889·4·15-22. Vertebrae-1o+ 14. Pleural ribs on third through tenth vertebrae. Epipleural ribs on first through eighth vertebrae. Anal fin-Two spines on first pterygiophore. Dorsal fm-Two spines on first pterygiophore. Eighth dorsal spine nearly covered over by scales. Pterygiophore-neural spine relationships the usual apogonine configuration. Predorsals-Three. Pelvic girdle-No comment. Pectoral girdle-No free medial extrascapular. Posttemporal with a spine. Jaws-Villiform bands of teeth on the dentary and premaxilla. Large supramaxilla. Suspensorium-Narrow villiform band of teeth on palatine; none on ectopterygoid. Branchial apparatus-Suspensory pharyngeal present. Five upper pharyngeal tooth patches. Junction between ceratohyal and epihyal smooth. Foramen in ceratohyal present. Seven branchio­ stegal rays. Infraorbitals-Six, shelf apparently absent on the third bone. Opercles-Preopercle serrated on the posterior and ventral edges, smooth on the ridge. Opercle with a single spine. Neurocranium-Basisphenoid present. Vomer with a narrow band of villiform teeth. Some ornamentation on frontals. Scales-Ctenoid. Lateral line complete. DISTRIBUTION. Holapogon maximus is known from very few specimens obtained along the Arabian coasts of Muscat and Oman and nowhere else. Nevertheless, if this species lives in deeper coastal water as the collection data suggest (83-100 m for the John Murray Expedition) then it may not be collected frequently. MATERIAL EXAMINED. Syntypes: BMNH 1887.11.11.66 (1, 173.9) Muscat. BMNH 1887.1I.II.68 (r, 176.4) Muscat, dried skeleton. Other material: BMNH 1889.4-15.21.-23 (3, 176.9-208-4) Muscat. BMNH 1939·5.24.848 (r, 82.4) South Arabian coast. ETYMOLOGY. Holos (entire, whole) and Apogon (a genus of cardinal fishes), in reference to the pro­ posal that this genus most closely represents the ancestor of the diverse genus Apogon. Gender, masculine. REMARKS. Holapogon differs from the other primitive genera in the Apogoninae (Table r) in possessing a total of nine dorsal spines, a perforated ceratohyal, seven anal rays and lacking an infraorbital shelf( 1). These same characters and the presence of a large supramaxilla and two pairs of uroneurals taken together distinguish Holapogon from all other genera in the Apogoninae (Fraser, 1972). Holap ogon represents, most closely, the probable ancestor which gave rise to Coran- 4 TABLE 1. COMPARISON OF SELECTED CHARACTERS FOR PRIMITIVE APOGONINE GROUPS. Holapogon Coranthus Glossamia Apogon (Yarica) Dorsal spines (total) 9 8 7 7 Predorsals . 3 3 Epipleural ribs 8 7-8 9 9 Pairs of uroneurals 2 2* I Preopercular edge serrated serrated smooth serrated Ceratohyal-epihyal junction smooth ? dentate smooth Upper pharyngeal tooth patches 4 Infraorbital shelf absent(?) ? present present Supramaxilla . large large large large Ceratohyal with foramen notched notched Intercalary facet not on otic bulla not on otic bulla not on otic bulla Extrascapulars. I I Teeth on premaxilla . villiform rows some canine villiform rows villiform rows dentary villiform rows sorne canine villiform rows villiform rows vomer . villiform rows few villiform rows villifonn rows villiform rows palatine. villiform rows few villiform rows villiform rows villiform rows ectopterygoid . none none villiform rows none Dorsal rays 9 IO 8-Io 9 Anal rays . 7 8 8-Io 8 Well-developed gillrakers I5-I7 I8 7-IO 8 Maximum known size (SL) 208 mm I3I 111111 245111111 I38 111111 * Previously, hard X -ray negatives were equivocal on this character. Soft X-ray negatives confirm the presence of two pairs of uroneurals. rhus-Rhabdamia lineages (Fraser, 1972: Pl. 44) especially the line leading to Apogon. The comple­ ment of primitive osteological characters present in Holapogon is more complete than in Glossanlia, Coranthus, Apogon (Yarica) or any other apogonid genus known to me. Therefore, Holapogon indicates that the Apogoninae are probably as primitive as, if not more primitive than the Epi­ gomnae. Several interesting patterns occur in the primitive apogonine genera. The species are all large fish by most standards within the Apogoninae reaching lengths of over 120 mm SL and up to at least 245 mm SL in the case of Glossamia (H.