25 September 1991 PROC. BEX. SOC. WASH. 104(3), 1991, pp. 468-473 MATSUBARICHTHYSINUSITATUS, A NEW GENUS AND SPECIES OF VELVETFISH (SCORPAENIFORMES: APLOACTINID AE) FROM THE GREAT BARRIER REEF Stuart G. Poss and G. David Johnson Abstract.—Matsubarichthys inusitatus is described from a single specimen, taken from One Tree Island, Queensland, Australia. It is readily distinguished from other scorpaenoids by its unique dorsal-fin formula (II, IV, 6) and ver- tebral formula (9 + 12 = 21), both with fewer elements than previously reported for a scorpaenoid; a low anal fin-ray count (11,4); a pelvic fin-ray count of 1,1; and the gill opening restricted to a pore dorsal to the opercle. Although the holotype is small (8.5 mm SL) and study of its internal anatomy thus limited, Matsubarichthys inusitatus is a relatively primitive aploactinid that can not be readily assigned to either of the two currently recognized aploactinid subfam- ilies, but may be a sister-group of the Bathyaploactininae. Neuston tow sampling conducted at One using Olympus SZH and Leitz Stereo TS Tree Island at the southern end of the Great binocular dissecting microscopes. B amer Reef resulted in the capture of a sin- Radiographic techniques suggested by gle predemersal-staged specimen represent- Tucker and Laroche (1984) were followed. ing a new genus and species of Aploactini- Radiographs were taken on a Koizumi Sof- dae (velvetfishes). tex SE X-ray unit, using Kodak ultrafine Aploactinids, of which 36 have been pre- grain SB single emulsion diagnostic radio- viously described, are widely distributed graphic film and Kodak Industrex R type throughout the Indo-Pacific. However, film. Exposure times of 6 to 12 sec at 50 to many remain extremely rare in collections 70 kv and 3 mA were employed. and thus poorly understood. Although it is The specimen was lightly stained with evident that velvetfishes are closely allied alizarin red S in 70% ethanol to show more with the scorpionfishes, particularly the clearly critical osteological features not vis- stonefishes and waspfishes (Matsubara, ible in the radiographs. The bones stained 1943a), the combination of presumptively only weakly, probably the result of pro- uniquely derived characters used to define longed storage in unbuffered formalin prior the family presents conflicting hypotheses to transfer to ethanol. of relationship. This paper describes an The abbreviation AMS designates the aploactinid scorpaenoid whose features un- Australian Museum, Sydney, where the ho- derscore this conflict. lotype and only specimen is deposited. Materials and methods.— Counts and head spine terminology used in this paper Matsubarichthys, new genus follow those of Eschmeyer (1969). Mea- Figs. 1, 2 surements were taken as specified in Poss Type species.—Matsubarichthys inusita- (1982), but using an ocular micrometer in- tus. stead of dial calipers. Illustration of the axial Diagnosis.—An aploactinid scorpaenoid skeleton was based on multiple radiographs fish with: dorsal fin II, IV, 6; anal fin II, 4; VOLUME 104, NUMBER 3 469 pelvic fin I, 1; 15 pectoral fin-rays; fin rays ible in radiograph, probably absent. First in all fins unbranched; no enlarged preor- two dorsal-fin pterygiophores enlarged and bital spines; no scales (except for lateral line); closely associated with cranium, both in- branchiostegal membranes connected to serting in first interneural space; first dorsal isthmus along entire length, opening to spine in supernumerary and second in serial opercular chamber restricted to a small pore association with first pterygiophore, both above tip of opercle; no slit behind posteri- spines enlarged and robust, the second no- ormost hemibranch; no pterygiophore in- tably so; third pterygiophore inserting in serting between neural spines of sixth and fourth interneural space and bearing no su- seventh vertebrae. pernumerary spine (Fig. 2). Neural spines Matsubarichthys inusitatus can be distin- of first two vertebrae small, directed for- guished readily from all other scorpaenoid ward, but not clearly visible in radiographs. fishes by its dorsal-fin, pelvic-fin, and ver- Neural spines of sixth and seventh vertebrae tebral counts, which are lower than those of without interdigitating dorsal-fin pterygio- any other species in the suborder. phore. Caudal skeleton with parhypural and Description.—Head large (Fig. 1), without hypurals 1,2,3, and 4 fused into single plate extensive spination. Lacrimal (infraorbital and to urostyle (hypural 5 not visible in 1), immovable, its posteroventral border radiograph); neural spine of preural cen- with 2 small, weak spines. Infraorbital bones trum wide and long; number of epurals and 2 and 3 strongly arched, with large infra- uroneurals not determinable. orbital canal pores opening as distinctly Etymology.—Named in honor of the late raised tubes. Small, tubular, fourth infra- Professor Kiyomatsu Matsubara, in recog- orbital bone present. Nasal bone tubular, nition of his pioneering and inspiring re- without spine. Anterior nostril, an attenuate search on scorpaenoid fishes. The gender is tube near tip of snout, extends over pre- masculine. maxilla. Interorbit wide, with ascending processes of premaxillae extending between Matsubarichthys inusitatus, anterior half of orbits. Mouth strongly up- new species turned. Teeth on upper and lower jaws; none Figs. 1, 2 on palatines. Presence of teeth on vomer uncertain. No slit behind posteriormost Holotype.-AMS 1.29395-001, 8.5 mm hemibranch. One infrapharyngobranchial standard length (SL). Australia, Queens- tooth plate. Epibranchial of first gill arch land, Great Bamer Reef, Capricorn Group, with a narrow, notably short uncinate pro- One Tree Island, 23°30'S, 152°05'E, neus- cess extending posteromedially from dorsal ton tow, Patti D. Schmitt, date, time, and ramus of bone at an angle of about 90°. depth of capture unknown. Three lateral-line pores on each side on low- Description.—Dorsal fin-rays II, IV, 6. er jaw, a fourth between lower jaw and pre- Anal fin-rays II, 4. Pectoralfin-rays 15 right, opercle on each side. Interhyal narrow 15 left. Caudal fin damaged, but relatively throughout its length, not expanded poste- long and rounded, without branched rays; riorly. Branchiostegal rays 6. Posterior 10 segmented rays (5 ventral; 5 dorsal), and opening of opercular chamber restricted to 4 unsegmented, procurrent rays (2 dorsal;.2 a small pore above tip of opercle, with bran- ventral). Lateral line with 6 long, tube-like chiostegal membranes firmly attached to scales, the first 3 very close together, the last isthmus. Ventral surface of urohyal narrow. extending over base of caudal fin. Gill rakers No pseudobranch. 1+4 = 5 (right). Vertebrae: 9 precaudal + Body covered with smooth skin, naked, 12 caudal = 21. except for lateral line. S wimbladder not vis- Head extremely large; notably depressed 470 PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON Fig. 1. Holotype of Matsubarichthys inusitatus in lateral view (AMS 1.29335-001, 8.5 mm SL). Broken tip of second dorsal fin spine reconstructed. (specimen with buccal cavity strongly flared of orbit just dorsal to third infraorbital bone; laterally on preservation). Lacrimal with another smaller spot deep and immediately small spinous points, but without enlarged ventral to opercular-hyomandibular hinge; spines or strong ventral lobes. Preopercle a smaller inclusion just dorsal to opercular with 2 short, somewhat blunt spines near opening, and a still smaller spot anterior to posterior margin of third infraorbital bone, this; two small spots on each side posterior the more dorsal the larger; additional, more to symphysis of premaxillae; large spot on ventrally located spines, if present, not vis- left side of isthmus; several minute dark ible through skin. Cheek with a few fleshy spots over ventral surface of iris, one lateral protuberances. Similar warty structures to urostyle. Small, densely melanic spots at scattered over ventral surface of head. bases of dorsal-fin spines, one between base Body scales absent, except for lateral line. of first and second, one posterior to fourth, Lateral-linescales extremely long, distinctly and a more conspicuous one posterior to tubular. The first 3 touch each other and fifth spine; spot anterior to anal-fin origin; appear, without high magnification, as a sin- another near base of last dorsal-fin ray (right gle elongate scale, except for presence of side only); one in axil of left (but not right) pores demarking their ends. pectoral fin. Dorsal fin originates above dorsal arm of Measurementsfor the holotype in mm are preopercle, with anteriormost two spines as follows (percent SLin parentheses): stan- well separated from remainder of fin; the dard length 8.5, head length 3.7 (44); snout first locked and directed anteriorly, the sec- 0.8 (9); orbit 1.0 (12); interorbit 1.0 (12); ond more robust, also locked, but directed jaw 1.4 (16); postorbit 2.0 (24); body depth vertically. Second spine broken (recon- 3.1 (36); predorsa!2.2 (26); anal fin 2.9 (34); structed in Fig. 1). Third and succeeding caudal fin 1.6 (19); pectoral fin 3.1 (36); pel- spines relatively narrow. vic fin 0.6 (7); dorsal spines, first 0.7 (8), Color in fife unknown. Color of specimen, second 0.9 (11), third 0.3 (4), fourth 0.6 (7), now in 70%ethanol, uniformly buff tan with fifth 0.7 (8), sixth 0.7 (8); anal spines, first several conspicuous, densely melanic inclu- 0.8 (9), second 1.1(13); width ofinterorbital sions that form distinct, deep-to-superficial ridge0.4 (5); caudal peduncle depth 0.9 (11); spots, most bilaterally symmetric: largest, snout to second dorsal spine 2.3 (27), to about V* to Vi size of pupil in ventral well third dorsal spine 4.0 (47), to fourth dorsal VOLUME 104, NUMBER 3 471 Fig. 2. Axial skeleton of holotype of Matsubarichthys inusitatus as reconstructed from multiple radiographs. Neural and haemal spines are not autogenous. Shape of anterior pterygiophores and epural region of caudal skeleton (indicated by hatching) cannot be determined from radiographs.