Bellottia apoda Giglioli, 1883

Nielsen, Jørgen G., Ross, Steve W. & Cohen, Daniel M., 2009, Atlantic occurrence of the genus Bellottia (Teleostei, Bythitidae) with two new species from the Western North Atlantic, Zootaxa 2018, pp. 45-57 : 53-56

Bellottia apoda Giglioli, 1883

( Figs. 8–10 )

Bellottia apoda Giglioli, 1883: 399 (type locality Gulf of Naples, Italy); Nielsen & Cohen 1968: 99 (selection and illustration of lectotype MZUF 5668); Nielsen et al. 1968: 245 (spermatophores); Maul 1976: 53 (off Portugal and on Great Meteor Bank southwest of Madeira); Orsi 1976: 38 (Ligurian Sea); Papaconstantinou 1984: 103 (Gulf of Evoikos, Greece); Berdar et al. 1977: 77 (Strait of Messina); Papaconstantinou et al. 1977: 279 (Gulf of Saronikos, Greece); Jardas 1979: 1 (Adriatic Sea); Sardou 1980: 69 (Villefranche-sur-Mer, South France; illustration of head pore system); Schwarzhans 1981: 103 (otolith); Allué 1984: 41 (near Barcelona); de Ranieri & Sbrana 1992: 177 (Northern Tyrrhenian Sea); Gramito & Coen 1997: 163 (Adriatic Sea); Anon. 2002 (Mallorca) - non Bellottia apoda ; Mytilineou et al. 2005: 230 (eastern Ionian Sea).

Material examined (16 specimens, SL 26–65 mm): Lectotype: MZUF 5668, SL 28, male, Gulf of Naples, trawl, Posidonia- bottom, 30 m, 20 Dec. 1882. - Paralectotype: MZUF 5669, SL 26, female, same data as for lectotype.

Non-type material: MMF 22516, SL 52–55, male and female, off Portugal, 37°41.5’N, 9°11.9’W, R/V Meteor, st. 11a-AT 7, Agassiz trawl, 500 m, 20 Jan. 1967. MMF. 22860, SL 39+ -65,?- male, off Portugal, 37°21.5’N, 9°12.5’W, R/V Meteor, st. 90d-AT 26, Agassiz trawl, 320–385 m, 22 June 1967. ZMUC P77698, SL 46, male, Great Meteor Bank, 29°50.2’N, 28°29.8’W, R/V Meteor, st. 159a, bottom trawl, 308–310 m, 18 July 1967. ZMUC P771651, SL 38, female, Central Adriatic Sea, 42°51’N, 14°44.6’E, bottom trawl, 247 m, 30 Jan. 1980. BMNH 1999.3.23.1, SL 41, male, Adriatic Sea, 42°48.5’N, 14°48.0’E, 18 June 1980. IIPB 454/ 1982 and 455/1982, SL 47–52, male and female, off Barcelona, 41°6.05’N, 2°3.1’E, bottom trawl, 446–516 m, 30 June 1981. ZMUC P771646-1650, SL 29–45, males, Central Adriatic Sea, 42°48.9’N, 14°41.5’E, bottom trawl, 217–219 m, 15 Apr. 1994.

Diagnosis. Bellottia apoda differs from all its congeners by having retrorse fangs on all dentigerous bones and lacking a distinct spine on cleithrum above base of pectoral fin and by the following combination of characters: body slender (13.0–16.0 % SL at origin of anal fin), spine on preopercular crest, caudal fin rays 6, anterior gill arch with 3–4 long rakers, precaudal vertebrae 12–13 and predorsal length (35.5–40.0).

Similarity. Judging from Table 2 , B. apoda seems to differ equally much from all the other Bellottia species making it difficult to select one species as the most similar. It differs from B. robusta e.g. by a more slender (13.0–16.0 vs 17.5–23.0 % SL) and more light-colored body, by fewer caudal fin rays (6 vs 7), fewer long rakers on anterior gill arch (3–4 vs 5–6), lacking spine on cleithrum (spine present) and shorter predorsal length (35.5–40.0 vs 44.0–49.5). From B. cryptica it differs e.g. by having fewer caudal fin rays (6 vs 7), more precaudal vertebrae (12–13 vs 10), fewer long rakers on anterior gill arch (3–4 vs 5–6) and presence of a spine on preopercular crest (spine absent). From B. armiger it differs e.g. by having fewer long rakers on anterior gill arch (3–4 vs 5), more precaudal vertebrae (12–13 vs 10), and origin of anal fin below dorsal fin ray 17–19 (vs 11). From B. galatheae it differs i. a. by having more rays in dorsal fin (83–94 vs 70–72), anal fin (68–82 vs 61), pectoral fin (21–26 vs 19–20), and a shorter predorsal length (35.5–40.0 vs 44.0–45.5).

Description. The principal meristic and morphometric characters are shown in Table 1 . Nielsen & Møller (2008, table 3) used the same set of characters as in the present paper based on 13 specimens three of which they examined while the characters of the rest were taken from the literature. For comparative reasons we have here only included characters from the 16 specimens examined by us.

B. apoda is thoroughly described and illustrated by Nielsen & Cohen (1968), Sardou (1980) and Gramitto & Coen (1997), rendering a detailed description here redundant. A few characters that have not been focused on in earlier papers are mentioned below.

Dentition. In males vomer, palatines and dentaries with many large, retrorse fangs; premaxillaries with small, pointed teeth besides fangs. In females fangs on all four dentigerous bones, but fewer and shorter than in males.

apoda armiger galatheae robusta cryptica Axial skeleton (based on radiographs): Tips of neural and haemal spines thin and pointed. Anterior neural spine 1/2 to 1/1 the length of second spine. Neural spines 2–9 depressed. Bases of neural spines 4–9 enlarged. Parapophyses present on vertebrae 7/8 to 12/13, pleural ribs on vertebrae 2/3 to 10/11 and epipleural ribs on vertebrae 4/5 to 11/12; the latter observed on few specimens only.

Otolith ( Fig.9 ). The 3.9 mm elongate sagittal otolith (from a 65 mm SL specimen, MMF 22860) is twice as long as high and twice as high as thick. Dorsal and ventral rim evenly rounded. Sulcus undivided, almost half as long as the otolith. No osteal channel.

Coloration: Fig. 8 shows a specimen after 27 years of preservation. It is uniformly light brown except for the dark eyes. A photo (provided by E. Gramitto, Ancona) of a specimen of unknown length from the Adriatic Sea taken just after capture shows a light brown body with darker vertical fins, a dark brown head with many spots and dark blue eyes.

Biology. All specimens have been caught on or near the bottom. The type material was trawled at 30 m on Posidonia -bottom and all specimens since then at depths of 150– 569 m. This is a viviparous genus in which the male transfers the spermatozoans packed in spermatophores into the female (Nielsen et al. 1968: 245). A 38 mm specimen (ZMUC P 771651) contained eggs up to 1 mm in diameter; embryos were not observed. Gramitto & Coen (1997: 170) observed embryos ready to hatch of 5 mm total length. According to Gramitto & Coen (1997:168), the stomach contents from 23 Adriatic specimens showed that the diet consisted of pelagic and benthic crustaceans with copepods as the most important prey.

Distribution. Fig. 10 shows that B. apoda is found from Greece to off Barcelona, off southern Portugal and furthermore on Great Meteor Bank at depths of 30– 569 m.

Remarks. B. apoda seems to be a rather common species in the Mediterranean as 128 specimens were caught in the Central Adriatic Sea between 1970 and 1994 (Gramitto & Coen 1997: 163). In order to determine whether the specimens from the East Atlantic Ocean differ from the Mediterranean ones, we have compared the set of characters used in Table 1 between these areas. Overlap was observed in all but one character, viz. number of pectoral fin rays: 21–23 in the Atlantic and 23–26 in the Mediterranean specimens, suggesting that there is no difference between the two populations.

Figures

FIGURE 8. Bellottia apoda. IIPB 454 / 1982. SL 52.

FIGURE 9. Bellottia apoda. MMF 22860. SL 65. Right sagitta: A—median view, B—dorsal view.

FIGURE 10. Records of Bellottia apoda. One record outside the map on Great Meteor Bank (29 ° 50.2 ’ N, 28 ° 29.8 ’ W).

Tables

TABLE 2. Comparison of diagnostic characters of Bellottia spp.

Dorsal fin rays	83–94	86	70–72	85–93	92
Caudal fin rays	6	6	6	7	7
Anal fin rays	68–82	74	61	75–88	84
Pectoral fin rays	21–26	22	19–20	23–25	23
Precaudal vertebrae	12–13	10	11	12	10
Total vertebrae	46–50	45	44–45	48–51	49
Long gill rakers	3–4	5	4	5–6	5–6
Spine on preopercle crest	yes	yes	yes	yes	No
Spine on cleithrum	no	yes	yes	yes	Yes
Predorsal in % SL	35.5–40.0	41.5	44.0–45.5	44.0–49.5	46.5
Depth at anal fin origin	13.0–16.0	17.5	16.5	17.5–23.0	17.0