Maurolicus cf. muelleri (Gmelin, 1789)

Van Hinsbergh, Victor W. M. & Helwerda, Renate A., 2019, Fish Otoliths from the Cabarruyan Piacenzian-Gelasian fauna found in the Philippines, Zootaxa 4563 (3), pp. 401-443 : 406-407

Maurolicus cf. muelleri (Gmelin, 1789)

(Figures 9–13)

1934 Maurolicus muelleri Chaine & Duvergier (re-pictured in Nolf etal., 2009)

1980 Maurolicus muelleri Schwarzhans W , p. 31, fig. 54

1995 Maurolicus muelleri Smale MJ, Watson G, Hecht T, p. 29, plate 11, E1–3

1999 Maurolicus muelleri Rivaton J, Bourret P , pp. 204-205, pl.93 fig. 13–16

2008 Maurolicus muelleri Tusset VM, Lombarte A, Assis CA, pp. 38-39, fig. 19 A1–3

2012 Maurolicus muelleri Lin CH and Chang CW, p. 75, plate 7

2013 Maurolicus muelleri Nolf D. plate 43

PLATE 1.

1. Ariosoma sp., RGM 962092, locality AndaDeVos. For this figure and remaining figures, all material derives from the Piacenzian or Gelasian Santa Cruz Formation of Cabarruyan Island or nearby Luzon Island, Philippines. Figures display otolith medial faces, which were imaged with light microscope Z-stack photography, unless stated otherwise.

2. Bathycongrus sp. Frost, 1933, RGM 962094, locality Anda2, SEM image.

3. Bathycongrus sp. Frost, 1933, juvenile, RGM 962095, locality Anda2, SEM image.

4. Bathycongrus sp. Frost, 1933 juvenile, RGM 962096, locality Anda3. (a) SEM image, (b) light microscopy image. 5. Congridarum sp., RGM 962093, locality Tiep2, SEM image.

6. Gonorynchus abbreviatus , RGM 962097, locality Roxas. (a) SEM image, (b) light microscopy image, (c) ventral profile, (d) lateral face, (e) ostial profile.

7. Argentina sp., RGM 962098, locality Anda4, SEM image.

8. Opisthoproctus grimaldii , RGM 962099, locality Roxas.

9. Maurolicus cf. muelleri , RGM 962104, locality Anda3.

10. Maurolicus cf. muelleri , RGM 962105, locality Anda3.

11. Maurolicus cf. muelleri , RGM 962101, locality Anda1.

12. Maurolicus cf. muelleri , RGM 962100, locality Anda1, SEM image.

13. Maurolicus cf. muelleri , RGM 962103, locality Anda3.

14. Maurolicus sp., RGM 962109, locality Anda1.

Material: 24 specimens in total. Anda1 (2) RGM 962100, RGM 962101 ,; Anda2 (7) RGM 962102 , RGM 962111 ; Anda3 (4) RGM 962103 , RGM 962104 , RGM 962105 , RGM 962106 ; AndaDeVos (2) RGM 962114 ; Roxas (8) RGM 962113 ; Tiep2 (1) in RGM 962116 .

Small otoliths (OL:OH=1.19–1.35) with a long pointed rostrum a sharp to rectangular postdorsal angle that separates two rather straight parts of the dorsal rim, of which the posterior one is considerably steeper than the anterior one. The anterior part of the dorsal rim starts at 1/3 of the sulcus, leaving the upper part of the rostrum covered by the ostium. The ventral rim is separated in two parts by a pointed postventral angle, which is accentuated by a prominent flag-like extension. The posterior part of the dorsal rim and that of the ventral rim form a variably rounded angle that can be prominent or shallow. The ventral rim contains irregular lobes; the dorsal rim varies in ornamentation from smooth to lobed. The slightly supramedian sulcus is divided in a deep ostium and a longer cauda that ends at considerable distance from the posterior rim. A crista superior lines the cauda only. The crista inferior consists of two separated parts that line either from ostium to the anterior part of the cauda or the posterior part of the cauda. The outer surface is smooth with a marked uprising at the central part. These otoliths are reminiscent of the extant Maurolicus muelleri , which is also known from Pliocene and Miocene deposits in Europe ( Nolf and Capetta, 1989; Steurbaut et al. 1979).

At present 15 species of Maurolicus are known, of which M. muelleri and M. javanicus are encountered in deep West Central Pacific waters, and M. japonicus is known from the North West Pacific, Japan, and Hawaii. The other Maurolicus species are only known from areas remote of the Philippines. However, many of these species have only been recognized from 1993, when Parin and Kobyliansky (1993) reported that the known pan-global M. muelleri represented a mixture of different species. While this asks for caution in using old references to M. muelleri , the presence of M. muelleri is well documented from the Mediterranean Sea, from which no other Maurolicus species have been reported ( Tuset et al, 2008). Comparison of the published data on M. muelleri otoliths provide a consistent picture. Several of our specimens (Figures 9–13) are identical to M. muelleri , while the ornamentation of a few specimens is rather pronounced. As they appear as one species, we have indicated it as Maurolicus cf. muelleri .