ANNALES • Ser. hist. nat. • 12 ■ 2002 ■ 2
original scientific paper	UDC 597.5(262.3-17)
received: 2002-07-10
LEBETUS GUILLETI (TELEOSTEI: GOBI I DAE) IN THE NORTHERN ADRIATIC SEA: FIRST RECORD AND DETAILS ON THE SPECIES' MORPHOLOGY
jurgen HERLER
Institute of Zoology, University of Vienna, A-1090 Vienna, AlthanslraSe 14 E-maii: Juergen.Herler@univie.ac.at
Marcela KOVAČIČ Prirodoslovni muzej Rijeka, HR-510QQ Rijeka, Lorenzov prolaz 1 E-rnail: Marceio.Kovacic@public.srce.lir
ABSTRACT
The occurrence of I ebetus guilleti ft. e Danois, 1913) is described for the first time from the northern Adriatic Sea, Croatian coastal waters. Light females (SL 12.1-17.4 mm! and five males <SL 10.6-12.5 mm) were collected in the Kvarner region, south of Rijeka on sandy substrates at depths between 6 and 13 m in >999 and 2001. A second small population was documented photographically along the western coast of /stria, near Rovinj in May 2002. The collected specimens were assigned to L. guilleti (Le Danois, 1913) by the following features: small body size, specific body coloration, complete loss of the head lateral line canals, presence of suborbital row a, limited number of head sensory papillae with two interorbital rows, elongate dorsal fin rays and meristu values of D2 1/7-8, A 1/4-5, F 14-15,! I 24 26 and VC 25-26. This recent finding enables a more detailed description of the morphology of this lath known species as given below. Morphometries, meristic values, lateral line system, coloration and skeletal features as well as ecology are described and compared with related gobiid genera.
Key words: Cobiidae, Lebetusguilleti, Mediterranean, northern Adriatic Sea
LEBETUS GUILLETI (TELEOSTE!: GOBIIDAE) IN ADRIATICO SETTENTRIONALE: PRIMA SEGNALAZIONE E DETTAGLl MORFOLOGÍCI
SINTESI
CU autori segnalano per la prima volta la presenta di Lebetus guületi fie Danois, 1913) nell'Adriatico setten-trionale, in acque croate. Otto femmine (SL 12.1-17.4 mm) e 5 mastín' (SL 10.6-12.5 mm) sono sía» trova!) ne lia re-gione quarnerina a sud di Fiume, su suhstrati sabbiosi tra i 6 c i 13 metri di profondità. Un'altra popolazione e stata scoperta più a nord, vicino a Rovigno. 67/ esemplari sono stati attribuiti alla specie Lebetus guilleti (Le Danois, ¡913) in base aile seguenti caratteristiche: piccole dimension! corporee, colora?ione corporea spécifies, assenza completa di canali lineari lateral! sul capo, presenza délia fila suborbitale a, numero limítate di papille sensorie sul capo con due file interorbitali, raggi délia pinna dorsale aliungati c vaiori meristici di D2 1/7-8, A 1/4-5. P ¡4-15, LL 24-26 e VC 25-26. Tale recente scoperta permette di daré una descrizione pib dettagliata délia morfología di questa poco nota specie. ! valor: moifometrici e meristici, il sistema lineare latcrale, la cobra*ione e le caratteristiche scheletriche nonché ¡'ecología vengono descritte e comparate con i correlatigeneri di go'cidi.
Parole chiave: Gobiidae, Lebetus guilleti. Mediterráneo, Adriático settentrionaíe
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introduction
The taxonomy within the genus Lebelus Winther, 1877 has been somewhat confusing since the two species Cob/us orca and C". scorpioides were described by Collett (1874) and assigned to a new genus by Winther (1877). These two species, which were mainly distinguished by coloration, turned out to be females and males of a single species exhibiting specific sexual di-chromatism (Miller, 1%1, 1963). The valid name for this species was supposed to be L orca initially, but had to be changed to L. scorpioides later (Miller, 1971!. At that time it turned out that two different species actually exist, both found within the material of L scorpiotdcs, indistinguishable by coloration patterns but by different postlarvai development and meristic characters of subadult specimens. The new species, described from specimens of soorplo/c/es-materiai, was designated as L. guilleti, raising the subspecies L. scorpioides guilleti by l.e Danois 0913) to species level (Miller, 1971). Both L. scorpioides (Collett, 1874) and L. guilleti (Le Danois, 1913) had previously been known only from the northeastern Atlantic boreal region, especially around the British Isles, the western Channel and south-western Scandinavia, and some early records made near the Strait of Gibraltar were considered doubtful (Miller, 1963). I he occurrence of the genus Lebetus in the Mediterranean Sea was reported first by Zander (1982), who found one specimen at Banyuls-sur-Mer/France in June 1979, which was assigned to L. guilleti. Now, two small populations of this species have been discovered in the northern Adriatic Sea along Croatian coast, one in the Kvarner region south of Rijeka and another along the western coast of Istria, close to Rovinj (Fig. 1), greatly extending the known distribution area within the Mediterranean Sea. These recently collected specimens exhibit distinct adult features and are therefore used to describe the morphology of this species. Morphometries, meristic values, lateral line system, osteology and coloration as well as a short note on the ecology of L. guilleti are provided.
MATERIAL AND METHODS
Material: 1 specimen; northern Adriatic Sea, Croatia, Kvarner region, Klenovica, south of Rijeka, close to Selce: 1 $,17.4 + 4.3 mm (PMR VP1022), 07.09.1999, leg. Kovacic. 12 specimens; northern Adriatic Sea, Croatia, Kvarner region, Selce, south of Rijeka: 1 5, 12.8 + 4.0 mm (CH 38:1) and 1 6, 12.6 + cl mm (CM 38:2), 12.04.2001, leg. Herler; 4 12.1 + 3.9 to 14.5 + 4.3 mm (CH 38:3, 5, 7, 8), 2 c?rj'. 11.3 + 4.0 mm (CH 38:6) and 11.9 + 3.9 mm (CH 38:4), 2 12.6 + 4.3 mm and 13.1 + 4.1 mm, 2 oV?, 10.6 + 4.0 mm and 10.9 + 3.6 mm (NMVV 94.569-94.592), 30.04.2001, leg. Herler.
Compared material: 1 specimen; western Mediterranean Sea. France, Banyuis-sur-Mer: 1 o, 12.9 + 4.6 mm (ZMH 7969), June 1979, leg. Zander.
The fish were collected with hand nets and photographed after anaesthetics (qulnakiine diluted with ethanoi 1:15) were dispersed from a squeeze bottle. The size of fish is given in SL+Ci (d-damaged). For os-teological descriptions, two specimens, 1 9 1--S + 4.0 mm (CH 38:1) and 1 8 12.6 + d mm (CH 38:2), were cleared and stained with alcian-blue and alizarin-red. Near Rovinj, six specimens were observed during a single dive in May 2002; two were documented photographically, but no collection took place.
Morphometries: Ab, anal fin base; Ad and Aw, body depth and width at anal fin origin; CI, caudal firs length; CHd, cheek depth: CP and CPd, caudal peduncle length and depth: D1b and D2b, first and second dorsal fin bases; £, eye diameter; H and Hw, head length and width; !, interorbital width; PI, pectoral fin length; PC), postorbilal length; SL, standard length; SN, snout length; SN/A and SN/AN, snout to anal fin origin and anus; SN/D1 and SN/D2, snout to origin of first and second dorsal fins; SN/V, snout to pelvic disc origin; Uj, upper jaw length; V/AN, pelvic disc origin to anus; Vd, body depth at pelvic disc origin; VI, pelvic disc length.
Meristics: A, anal fin; C, caudal fin; D1, D2, first and second dorsal fins; I.L, scales in lateral series; P, pectoral fin; TR, scales in transverse series; V, pelvic disc; VC, number of vertebrae.
Collections: CH, collection Herler; NMW, Museum of Natural History Vienna; PMR, Museum of Natural History, Rijeka.
RESULTS Morphology
Identification: The specimens were assigned to Lebetus guilleti (le Danois, 1913) by meristic features D2 1/7-8, A 1/4-5 and 25-26 vertebrae. The small body size, typical habitat choice and conspicuous brown and white body coloration also enables easy discrimination in the field. Slight differences in the coloration between L. guilleti and the congeneric L. scorpioides are given In Table.?..
General morphology: Body proportions are given in Table 1. Body small, laterally compressed with dorso-ventral symmetrical shape. Head relatively small and slightly depressed, with large eyes longei than snout. Lyes positioned dorsolateral resulting in narrow interorbital space. The mouth is oblique with short upper lip extending back only to below anterior edge of orbit. Anterior nostril a short tube without, process from rim, posterior nostril with only slightly ascending rim. Bran-chiostegal membrane attached to side of isthmus at ventral origin of P, and membrane not fused across isthmus.
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C. Mediterranean Sea
Fig. I: Mediterranean Sea with northern Adriatic Sea (enlarged) indicating the observation sites of Lebetus guilleti in the Kvarner region at Selce and Klenovica (1) and along the western coast of Istria near Rovinj (2). Si. 1: Sredozemsko morje s severnim Jadranom (povečano<) in z lokalitetami pri Sekah in Klenovici (!) v Kvarnerjti in v bližini Rovinja vzdolž zahodne istrske obale (2), kjer je bila opazovana in dokumentirana vrsta Lebetus guilleti.
Tab. 1: Morphometric values in both sexes of the northern Adriatic lebetus guilleti. n = number of specimens; s -standard deviation.
Tab. 7: Morfometrične vrednosti pri obeh spolih severnojadranske vrste Lebetus guilleti. n = število primerkov; s = standardni odklon.
		Lebetus guilleti (l.e Danois, 1913)					
Sex					OP		
SL		10.6 -12.5 mm			12.1 17.4 mm		
n		5			8		
		range	mean	s	ranee	mean	s
%Sl,	H	29.8-30.6	30.1	0.3	29.9-32.5	30.9	0.8
	Hw	17.2-18.9	17.9	0.6	16.9-21.8	18.3	1.5
	SN/D1	36.7-38.7	37.8	0.8	36.9-39.4	37.9	1.0
	SN/D2	58.0-61.3	59.8	1.3	58.4-61.5	59.9	1.1
	SN/AN	52.3-58.3	55.9	2.0	56.3-60.6	58.5	1.5
	SVA	58.9-62.8	61.4	1.4	61.9-66.7	64.7	1.5
	SNA'"	30.5-34.5	32.6	1.7	30.4-34.4	32.3	1.4
	CP	22.7-24.5	23.6	0.7	21.8-26.8	23.4	1.5
	D Hi	10.7-12.3	If.5	0.6	11.2-15.5	12.3	1.4
	02b	21.4-25.5	23.6	1.4	21.5-25.3	23.0	1.3
	Ab	14.0-17.9	15.7	1.7	13.3-16.6	15.0	1.0 j
	CI	32.9-37.7	34.9	1.9	24.7-34.0	31.3	2-3 I
	PI	26.5-28.9	27.6	1.1	21.8-27.6	25,2	1.6
	VI	28.2-33.1	31-1	1.7	27.6-32.4	30.4	1.5
	Vd	17.9-20.1	18.9	0.9	16.6-21.3	18.6	1.6
	Ad	15.3-19.6	17.3	1.5	14.6-18.0	16.6	1.1
	Aw	10.3-13.0	11.2	1.0	9.2-13.2	11.0	1.2 1
	CPd	10.4-12.2	11-1	0.7	9.6-11.5	10.4	0.6
	V/AN	23.9-26.2	25-0	0.7	26.3-30-0	28.5	1.3
	E	9.1-10.8	9.9	0.6	8.6-10,8	9.9	0.8
% CP.	CPd	42.9-51.9	46.9	3.3	39,6-50.2	44.5	3.0
% H.	SN	22.6-27.1	24.8	1.4	22,0-27.8	25.1	2.0
	E	30.0-35.3	32.9	2.0	28,8-35.2	32.1	2.1
	PO	44.8-48.3	<17.1	1.3	44.7-48.8	46.5	1.4
	CHd	11.7-15.1	13.2	1.4	11.8-14.9	13.5	1.1
	Hw	56.8-61.8	59.4	1.9	54.4-73.1	59.3	5.6
	Ul	27.4-33.7	30.6	2.3	28,6-35.8	31.7	2.4
. % E.	1	18.2-23.2	20.2	1.7	11.3-18.5	14.8	2.8
_ V/AN,	VI	118.0-130.6	124.3	4.3	98.0-115.4	106.8	5.2
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Fig. 2: Fin shapes in Lebetus guilleti. (A) D1 and D2, o, 10.6 + 4.0 mm; (B) ventral fin, S 10.9 + 3.6 mm. Scale bar = 7 mm.
SI. 2: Oblike plavuti vrste lebetus guilleti. (A) D1 in D2, ¿, 10,6 + 4,0 mm; (B) trebušna plavut>, S 10,9 + 3,6 mm. Merilo - 1 mm.
Teeth in both jaws in three rows, enlarged in first of these, erect and caniniform. Sexual dimorphism, apart from sexual dichromatism described below, can be seen in some body proportions (Tab. II. females show a longer abdomen through higher value-s in SN/AN, SN/A and V/AN (all in % SL). The caudal and pectoral tins (CI
and Pi in % SI.) are somewhat shorter ;n in inferor-bital width (I in % If) the 99- aie exceeded by the So-
Fins (Pig. 2): D1 VI; 02 1/7-8 (7:8, 8:5); A 1/4-5 (4:4, 5:9); C (branched rays) 8-10 (8:3, 9:8, 10:1, d:1); P 1415 (14:9, 15:4); V 1/5+1/5. Rays of median fins 01, D2 and A elongated especially in males. In P, all rays are within membrane. V truncate, V4 and V5 usually of same length or latter slightly shorter, with no anterior membrane developed. C slightly rounded to truncate Segmented fin rays branched only in C and V.
Scales: Li. 24-26 (24:3, 25:4, 26:4, d:l). TR 7-8 (7:12, 8:1). Squamation occurs only on the trunk, while nape, predorsa! area back to end of D1 base, opercie, breast and belly are naked. The scales on the trunk are ctenoid and are easily lost in preserved specimens.
Vertebrae: VC 25-26, including urostyle (10 precau-dal i 15 caudal vertebrae and 11 + 15 respectively).
Lateral line system <Fig. 3): No head canals present and a iow number of superficial neuromasts. Rows of papillae were lettered according to Miller (1963) as given for L. scorpioides (formerly L. orca) bul adapted to a more recent nomenclature (Miller, 1986) in some rows. Number of papillae are given as the most frequent, values in parentheses.
1.)	Preorbital: Snout with only few papillae. Row rs (2- 5) close to each other arid to posterior nostril, row 5 (1) more distant on anterior edge of snout. Rows c with C (1) near posterior nostril and <:' (5) downward from anterior nostril.
2.)	Suborbital: Row a (5) with longitudinal extension termed row a' (2) from poste-ior edge of orbit. 3 to 4 papillae irregularly distributed on upper cheek and therefore difficult to assign to row b or c. Row d (1 2) on posterior edge of lower jaw.
Tab. 2: Inter- and intraspecific comparison of morphological differences within the gobiid genus Lebetus from different geographical regions.
Tab. 2: Inter- in intraspecifična primerjava morfoloških razlik znotraj rodu ! ebetus iz različnih geografskih regij.
Species	•HH'imiM^^^e' ................ L scorpioides	L. guilleti	L. guilleti
Location	north-eastern Atlantic	north-eastern Atlantic	northern Adriatic
Reference	Miller (1963, 1971)	Miller (1971)	this study
	n = 76	n = 6	n = 13
Features:			
D2 soft rays	9-10	7-9	7-8
A soft rays	7-8	5-6	4-5
Vertebrae	27-29	25-26	25-26
D1 shape (<5'o)	enlarged, rounded	?	smaller, triangular
D1 coloration {<$$)	dusky yellow, white edged	?	grey, 2 yellow bands
02 coloration (<?<?)	4 broad red bands	?	6 yellow bands
S Postlarvae (5-6 mm):			
j Ventral fin length	< 10% SL	> 10% SL	?
j Melanophores (A base)	absent	present	?
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A
F'g. 3: Lateral line system of the northern Adriatic Lebetus guilleti; S, 10.9 + 3.6 nun. (A) lateral view, (B) dorsal view, (C) ventral view of head. Scale bar - 1 mm.
SI. 3: Sistem pobotnice pri severnojadranskih primerkih vrste Lebetus guilleti; S, 10,9 + 3,6 mm. (A) glava s strani, <bJ s "rbtne strani, (C) s trebušne strani. Merilo ~ 1 mm.
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Fig. 4: Skeleton of the northern Adriatic Lebetus guilleti; 12.8 + 4.0 mm (A - D) and Q, 12.6 + d mm (E), (A) Jaws, suspensorium and opercle series; (B) pectoral girdle; (C) pelvic girdle; (D, E) last vertebrae and caudal skeleton; all in lateral view. Bones white, cartilage stippled. Scale bar = 1 mm. AN, retroarticular; ART, anguloarticular; CL, clcithrum; CORcoracoid; D, dentary; EPU, epural píate; HS, Itemal spine; HYO, hyomandibular; HYP, hypu-ral; IOP, interopercle; MPT, meiapterygoid; MX, maxilla; NS, neural spine; OP, opercle; PAL, palatine; PHYP, parhypural; PMX, premaxil/a; POP, preopercle; PRC, procurrent cartilage; PTG, ectopterygoid; PTM, posttemporal; QU, quadrate; RAD, ra dials; SCA, scapula; SCL, supracleithrum; SOP, subopercle; SV, symplectic. Si. 4: Skelet severnojadranskih primerkov vrste Lebetus guilleti; 12,8 + 4,0 mm (A - D) in 12,S + d mm (E). (A) Čeljusti, oporni in operkularni nizi; (B) oplečje; (C) okolčje; (D, E) zadnja vretenca in obrepni skelet; vse s pogledom s strani. Kosti bele, hrustanec pikčast Merilo = 1 mm.
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3.)	f'reopercub-mandibular: Papillae of posterior part of external row e (1-2) along preopercle, distant from each other, those of the anterior part (2) close to each other at posterior edge of lower jaw. Internal row i in three parts with superior section (2) along upper pre-opercle, posterior section (6) along lower preopercle, and anterior (4) section along lower jaw. Mental row f (2) in clear distance from rows e and /.
4.)	Oculoscapular: Row t/' (1) ^n the middle of postorbital region. Row x II) more posterior, with row u2 (3) below this. Row xy (1) above upper end of opercle. Row z {1) superior to superior section of row i. Axillary series represented by rows a< (2), as7 (1), as"'' (1). ¡a' (1) and ia2 (1) clearly separated.
■>.) Opercular: Transverse row ol divided into upper (2-3) and lower (1-2J set i on. Rows os (1-2) and oi (1-2) present.
6.)	Anterior dorsa:: Row n G) with section of two papillae along posterior edge of orbit and one in distance from orbit. Rows g and m (1-3) together and difficult to assign, in most cases forming a triangle on each side. Row h (2-3) usually before origin of 01.
7.)	Interorbitai: Row p (1) in anterior and p2 (1) n middle part of interorbitai space on each side close to orbit.
8.)	Trunk: Dotsvti series with ld! (1) near 01 origin. ¡ct (1-2) below posterior part of Dl and id1 (2-3) on upper edge of caudal peduncle. Median rows Itm in 7 to 10 short (1-3) transverse rows. Ventral series with lv' (23) between origins of P ant: V, Iv2 (2-3) in middle of abdomen and ¡v3 (2-3) above anus.
9.)	Caudal: Three papillae in short transverse row at C origin. One median longitudinal row (2-4) originating :Yom middle papillae of former row.
Osteology (Fig. 4): Both stained specimens well ossified. Apart from vertebrae and pterygiophores no major differences in the skeleton of the stained male and female were observed. Hyoid (not shown in Fig. 4): 5 branchiostegal rays, first thin ant.) attached to slender antenor process of axe-shaped anterior ceralohyal. Rays 2, 3 and 4 on broad part of the latter. Firth blade-like ray attached to posterior ceralohyal
1.) jaws, susperisorium and opercular series (Fig. 4a): Teeth present on premaxiila and dentary. Both elements with three tows of caniniform teeth at symphysis, decreasing to one row posterolateral!'/. Teeth in outer row-enlarged. Premaxiila with long ascending and articular process, posterior part short, joining only the anterior half of maxilla. Postmaxiilary process absent. Maxilla broad only in first two thirds, lasl third splint-like, overlapping dentary plate and dorsally anguloarticular when mouth opened. Palatine slender with thin process in setting in anterodorsal end of maxilla. Ectopteiygoid as small bone between palatine and quadrate. Angulnar-ticular inserts in dentary with pointed anterior process,
while the ventral ramus is plate-like. Posterodorsal, an-guloarticuSar articulates with quadrate. Retroarticular small, ventromedial at posterior end of anguloarticular. Metapterygoid small, laterally overlapping hyoman-dibular arid anterodorsal half of symplectic. Latter attaching to quadrate medially. Posterior ramus of quadrate overlapped by anterior ramus of preopercle, latter dorsatly fixed between plate and inferior process of hyomandibular.
2.)	Pectoral girdle (Fig. 4b): Post-temporal with two processes and thin plate, which overlaps the articulation with supradeithrurn. Cleithrum relatively straight in lateral view, strongly bifid at dorsal end and with ascending plate from middle part. In lower third bony plates, which join the pelvic intercleithral cartilage on both sides. Ventral intercleithral cartilage between ventrally joining left and right cleithrum. Coracoid inserting close !o ventral bony plate of cleithrum. Scapula unossifted, slender with dorsal foramen. Four large proximal radials surrounded by cartilaginous areas. The tiny distal radials are cartilaginous.
3.)	Pelvic girdle (Fig. 4c): Pelvis joining large pelvic intercleithral cartilage anteriorly. Pelvic fin rays insert on cartilaginous posterior rim of pelvis. Medially rod-like bones project forward from posterior inner rims of pelvis.
4.)	Axiaf skeleton and median fins: 25-26 vertebrae, including urostyle. Variation was found in number of precaudat vertebrae with 10 and 11, respectively. The number of caudal vertebrae was 15 in both stained specimens, with hernal arches closed. In lateral view, first five vertebral centra becoming progressively longer and less wide backwards, first two centra shorter than wide. The absence of one precaudal vertebra in the female specimen (CF1 38:1) seems to impinge on the arrangement of the pterygiophores of Dl and D2. 01 shows the formula 3-2301 instead of 3-2211 as exhibited by the male (CH 38:2). Two free interneural spaces between pterygiophores of D1 and D2 and therefore three pterygiophores of D2 before the first caudal vertebra in the male, but only two in the female. In both specimens, the number of proximal pterygiophores in D2 resembles the count of all fin rays, that in A only the count of soft rays. Pleural ribs are found on third to last precaudal vertebrae, therefore 8 and 9 in number, attached to parapophyses of vertebrae, Epipleural ribs on second precaudal vertebra to fourth caudal vertebra (13 and 14). First epipleural rib attached to second vertebra, remaining precaudal attached to pleural ribs. First two caudal epipleural ribs attached to vertebrae, last two loose contact.
5.)	Caudal skeleton (Figs. 4d, 4e): Neural spines and hemal spines of fast three vertebrae enlarged, especially last hemal spine expanded, larger in male. Dorsal and ventral procurrent cartilage slender, joining large epurai
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1
Fig. 5: Coloration of the northern Adriatic Lebetus guilleti. Male (A) and female (B) in the natural habitat. More colourful variations arc shown after narcotisation and/or recent preservation in formaldehide: (C) S, 12.6 + d mm, lateral view; (D) 13.1+4.1 mm, ventral view. Scale bar = 5 mm.
Fig. 5: Obarvanost severnojadranskih primerkov vrste Lebetus guilleti. Samec (A) in samica (B) v naravnem življenjskem prostoru. Bolj pisane barve se pokažejo po omamljenju in/ali po shranitvi primerka v formaldehidu: (C) S, 12,6 + d mm, pogled s strani; (D) 13,1 +4,1 mm, pogled s trebušne strani. Merilo = 5 mm.
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plate and last hemal spine, respectively. Ossification of former less in male, notched on dorsal rim. Parhypural and hypural 5 small splint-like bones. Two large hypural plates, hypural 3+4 and hypural 1 +2, former fused with urostyle, latter inserting ventral to ural centrum. All fin rays associated with large hypural plates branched. One ray of both dorsal and ventral of those branched rays articulated, but not branched.
Coloration. Within the natural habitat, the body coloration is well adapted to the substrate (Figs. 5a, 5b). Basic coloration is a broad brown and white oblique transverse pattern. Head greyish in males, brownish in females, followed by a white interspace below D1 base. Anterior edge of following brown transverse bar oblique, running from D2 origin to ventral middle of belly. Large bright spot ventrally interrupts this bar in both sexes. Posterior edge at beginning of caudal peduncle curved. Caudal peduncle almost white. Before C origin narrow brown transverse band with oblique anterior edge from dorsal origin of caudal fin to ventral beginning of last quarter of caudal peduncle. Brown pattern dorsally slightly extending on to caudal fin. All brown vertical bars are well separated from white interspaces by dark margins. Proximal half of pectoral fin white, distal half transparent to dusky. C transparent. Sexual dimorphism especially shown in dorsal fin coloration.
Males (Fig. 5a): D1 greyish with yellow oblique bands, one narrow in lower third and one broad in upper third; edged white. D2 edged black, especially with large blotch in upper anterior corner. Six oblique narrow yellow bands below dark edge running across fin rays and separated from one another by dark edges and transparent interspaces. V and A usually dusky. Lips yellow to light orange.
Females (Fig. 5b): D1 white to light grey with a small green eye spot between fifth and sixth fin rays. D2, V and A transparent. Lips red, especially in posterior half.
A more colourful pattern in body coloration is shown when the fish are narcotised, kept in a photographic aquarium or recently preserved in formaldehyde (Figs. 5c, 5d).
Males: When captured, head becomes yellowish with some orange spots on cheek, snout and upper lip light orange. First bright interspace on trunk shows 4 narrow but conspicuous brown to orange-red vertical bands extending on to belly. Middle parts of following brown vertical bar with large red parts. Yellow bands in D1 and D2 and dark edge of D2 become more distinct. A, distal half of V and ventral part of P turn dark grey to black. Proximal half of V red.
Females: Head and broad brown trunk bar with dark red regions. Bands within first white interspace on trunk not distinct, somewhat irregular and coloured light brown with red dots. D1 turns dark grey with two to three slight red bands, eye spot still visible. D2 dusky with 4 red oblique bands. A and distal half of V black.

Fig. 6: Grain size distribution of the sediment in the habitat of Lebetus guilleti in the northern Adriatic Sea. SI. 6: Granulacija sedimenta v habitatu vrste Lebetus guilleti v severnem Jadranskem morju.
Breast, proximal half of V and base of A red. P bright with dark spot in centre.
After preservation in 70% ethanol, the specimens retain only brown and black coloration with white interspaces. Females exhibit darker mottling on head, hreast and in first dorsal fin. Narrow red bands below D1 get lost or turn light brown. In both sexes, broad brown oblique bar on trunk brightened in centre, therefore mainly represented by dark margins. Brown band on caudal peduncle well visible. Black margin of D2 in males stays distinct. Distal half of V and A in both sexes black. P in males with ventral half dusky, in females with black spot in the centre.
Ecology
All specimens observed and collected were found on a bottom consisting of a highly biogenic coarsely structured sand as shown by the grain size distribution (Fig. 6). The fish were found within a depth range of 6 to 13 m. The shallowest discovery was near Klenovica, Kvarner region, where one specimen was collected at 6 m depth. At Selce, Kvarner region, the specimens occurred frequently at depths between 11 and 13 m, and between 7 and 10 m at Rovinj. The habitats investigated near Rovinj and in the Kvarner region show high similarities, characterised by sandy bottom, which is interrupted by bedrock areas at depths of about 5 to 9 m, dividing the sandy areas into small insular spots. The fish were found in both large areas and in small insular spots of sand bottom. The specimens were discovered accidentally when the anaesthetic was dispersed from a squeeze bottle over the sediment. The tiny fish exhibit a very cryptic behaviour with few movements and high colour adaptation, which makes them almost invisible. The fish can be discovered by a diver when moving one hand forward flowly and directly over the sand surface, which causes flight reactions. The fish appear to dwell
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on the sand sutface and it seemed quite unusual when digging in the substrate, as observed in one specimen, when chased with the anaesthetic. The distribution is somewhat aggregated, because most specimens usually occurred close to each other, while large neighbouring areas revealed no fish. The highest abundance observed was about 2 ind./tn2. Co-occurring epibenthic fish species were especially Gob/us roulei, Buenia aftlnis and Pomatoschistus bathi, which dwell on the same substrate in high abundance. All collected specimens are adult and sex determination was possible from coloration, differences in fin shape and the typical sexual dimorphism of the urogenital papillae. Within the material collected only one size ( lass, obviously the one year-c.lass, occurs. The specimens collected in spring range from 10.6 to 14.5 mm SL. This includes the specimen collected in the western Mediterranean by Zander (1982) in June 1979 with 12.9 mm SL. The only collection made in autumn revealed a larger specimen of 17.4 mm SL. Collected at the same time, females are larger than males within this one size class.
DISCUSSION
Since Miller (1971, 1986) suggested two species within Lebetus Winther, 1877, due to different postlarval developments of pelvic fins and pigmentation and different rneristic values of anal fin, second dorsal fin and vertebrae, the northern Adriatic specimens can be assigned to L. guilieti (Le Danois, 1913) (Tab. 2). Counts of fin rays and vertebrae are significantly higher in L scor-pioides than in L. guilieti and therefore enable identification also of subadult or adult bentbic specimens (Miller, 1971). The western Mediterranean specimen found by Zander (1982) at Banyuls (Franee) exhibited the very typical coloration (Zander, pers. comm.) as described above for the northern Adriatic specimens and represents a male L. guilieti. The greater number of specimens investigated now increases the knowledge of the morphology of this species and indicates a wider anal fin ray count of I/4-6 (Tab. 2).
Apart from meristics, there are differences between L. guilieti and L scorpioides in some specific coloration patterns. In particular, the first dorsal fin in males of the former is less uniformly coloured- The second dorsal fin exhibits more but narrower oblique bands. The dorsal fins are also important for sex discrimination in both species (see also Miller, 1963). Body coloration seems to be more differentiated in L. guilieti with vertical bars occurring on the abdomen in both sexes but especially in males. Also the dark bar on the posterior caudal peduncle appears more evident, expanding more anteriorly on ventral side. Nevertheless, the basic coloration patterns of both species is very similar. In osteology, the main differences occur in the number of vertebrae, this being lower in L guilieti. Other features show no major
differences. The cleithrum in L guilieti appears straighter in lateral view and somewhat elongated on its bifid dorsal end. The caudal skeleton appears less strong, with the roots of the neural and hemal spine expanding over entire length of vertebral centra only in the last vertebra.
Similarities of the genus Lehetus with other Mediterranean gobies relate mainly to Speleogobius trigloides Zander and jeSinek, 1976. Although there is an anterior oculoscapuiar head canal developed in the latter, the arrangement of the superficial head sensory papillae is very similar (compare with Zander & jelinek, 1976; Miller, 1986). Meristics of fin rays and scales are almost the same as those of L. guilieti. As predorsal scales are only present in S. trigloides, Lebetus may be regarded as more specialised by reduction of squamation. In both the anterior membrane of the ventral disc is lost. They also conform in small body size and in a conspicuous colourful body coloration, which can be suppressed by Lebetus due to substrate adaptation. These similarities suggest a close relationship and possible common ancestry for Speleogobius and Lebetus, with some features more generalised in the former.
Affinities of the genus Lebetus with different 'sand-goby' genera (Pomatoschistus, Cobiusculus, Ktih powitschia and Economidichthys) and related genera are described by Miller (1963) and McKay & Miller (1997). High similarities are exhibited with Buenia lljin by the arrangement of head sensory papillae and merts-tic counts, although the latter being lower in L. guilieti. Both genera conform in a very limited number of head neuromasts basically arranged longitudinally and in dwelling sand bottom. Buenia is more generalised in possessing a complete head canal system. Further differences exist in the dorsal pterygiophore formula, being derived with 1221 in Buenia, and in higher variations in the counts of precaudal and caudal vertebrae in Lehetus (McKay & Miller, 1997).
Concerning the ecology of L. guilieti in the northern Adriatic Sea, several observations confirm the results of Zander (1982) and Miller (1971) in the western Mediterranean Sea arid northern Atlantic. Both the habitat choice of rough biogenic sand bottom and the cooccurrence of Pomatoschistus bathi in high abundance correspond with Zander (1982). The substrate inhabited by the small population near Rovirij, where about six specimens were observed during one dive, resembles that off Selce. Highly biogenic coarse sand is interspersed with large rocky boulders. The habitat choice of coarse deposits and the occurrence in quite shallow waters were also described by Miller (1971) for the north-eastern Atlantic specimens, in contrast to L. scor-pioides from the north-east Atlantic, which is supposed to mature in the second year of life (Miller, 1963), L. guilieti seems to attain sexual maturity within the first year of life in the Mediterranean. Since the one year
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Wrçrn HERltR « M»rcth KOVACtC; UWUS C LU I £TI (THfOS Î0- GO8II0AÜ IN TH{ NORTHERN ADRIATIC SR A: FIRST rIcORÖT
class, represented by only tiny specimens collected in the Mediterranean until now, appears to be the only size class, a semelparous reproductive strategy is possible. The very small size of this fish within the Mediterranean may explain why this species had not been found in that region for such a long time.
ACKNOWLEDGEMENTS
We are indebted to P. j. Miller for comments on the manuscript and to C. D. Zander for essential information and photos of his record of L. guilleti in the western Mediterranean. Thanks to H. Wilkens and G. Schulze from the Zoologisches Museum Hamburg for lending this specimen. For helpful assistance during the field work we would like to thank P. Zoida and M, Kirincic. Two anonymous reviewers provided constructive criticism.
LEBETUS GUILLETI (TELEOSTEI: GOBIIDAE): PRVI ZAPIS TE VRSTE IZ SEVERNEGA JADRANSKEGA MORJA iN PODATKI O NjFNI MORFOLOGIJI
Jiirgen HEKLtR
Institute of Zoology, University of Vienna, A-1090 Vienna, Althanstrafie t A fc'-maii: )uergen.Herler®univie.ac.at
Marcela KOVAČIČ Prirodoslovni muzej Rijc-ka, HR-51000 Rijeka, lorenzov piolaz t E-roaii: MaTcelo.Kovacir.@public.srce.hr
POVZETEK
Avtorji članka poročajo o prvem opazovanju vrste Lebetus guilleti (Le Dartois, 1913) iz družine glavačev v obalnih vodah severnega Jadrana. Leta 1999 in 2001 so v Kvarnerju južno od Reke dokumentirali osem samic (5L 12.117,4 mm) in pet samcev (SI. 10,6-12,5 mm) na peščeni podlagi v globinah med 6 in 13 metri. Druga manjša populacija te vrste je bila fotografirana maja 2002 ob istrski obali v bližini Rovinja. Zbrani osebki so pripadali vrsti 1. guilleti (Le Dancis, 1913), kar je bilo ugotovljeno po njihovih naslednjih značilnostih: majhno telo, specifična barva telesa, popolnoma brez bočnih naglavnih kanalov, obstoj podočesnega niza a, omejeno število naglavnih čutilnih papil z dvema medočesnima nizoma, podaljšani žarki hrbtne plavuti in merislične vrednosti D2 1/7-8, A 1/4-5, P 1415, l.L 24-26 in VC 25-26. Ta nedavna odkritja so omogočila natančnejši opis morfologije te malo znane vrste. Avtorji podajajo njene morfometrične podatke, merislične vrednosti, parametre v zvezi s pnbočnico, obarvanost, skeletne značilnosti in ekologijo in L. guilleti primerjajo s sorodnimi rodovi glavačev.
Ključne besede: Gobiidae, Lebetus guilleti, Sredozemlje, severno jadransko morje
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