Mephisto fraserbrunneri Tyler 1966
Creators: name: Bemis, Katherine E.
name: Tyler, James C.
name: Psomadakis, Peter N.
name: Ferris, Lauren Newell
name: Kumar, Appukuttannair Biju
Publisher: name: Zenodo
Year: 2020
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Actinopterygii
Tetraodontiformes
Triacanthodidae
Mephisto
Mephisto fraserbrunneri

description: Mephisto fraserbrunneri Tyler 1966
Devil’s Spikefish
Mephisto fraserbrunneri Tyler 1966a: 1–5 (original description; based upon a single specimen, holotype: ANSP 103314, type locality: eastern Bay of Bengal, Andaman Sea, off southern Myanmar, Indian Ocean, 10°39′N, 97°06′E, R/ V Anton Bruun, Station 22B, 159 fathoms (= 290 m), 24 March 1963; etymology: species named in honor of A. Fraser-Brunner for his pioneering revisions of many families of plectognaths). Tyler, 1966b: 4 (considered to be a generalized triacanthodid). Tyler, 1968: 133–138 (description, proposed relationships, illustration of pelvis and scales, photograph of BAH IOES-201 (= ZMH 5629)). Tyler, 1980 (summary of proposed relationships as given in Tyler (1968)). Shcherbachev et al., 1986: 208 (description of USNM 350153; specimen identified as Mephisto sp. because scales have several spinules that are bifurcate). Tyler, 1986: 887 (Mephisto included in key). Gorelova et al., 1993: 225 (mesobenthic species, captured on Error Seamount; stomach contents of 105 mm SL specimen (now USNM 350153) contained chitin fragments and peropods of a gammarid). Manilo and Bogorodsky, 2003: S123 (listed only). Matsuura, 2015: 75, 76 (range includes Somalia, Arabian Sea, and Andaman Sea). Mullasseri et al., 2017: 76–81 (comparison of seven specimens from Andaman Islands of putative Paratriacanthodes retrospinis with data from Tyler (1968) on M. fraserbrunneri, but critical diagnostic measurements, such as length of gill opening, not provided, and the single specimen illustrated (figs. 2, 3, both in color; fresh and after preservation of the same specimen) of putative P. retrospinis has the typical blotchy color pattern and long gill opening that is diagnostic of M. fraserbrunneri rather than the horizontally lined pattern and shorter gill opening typical of P. retrospinis; these specimens require re-examination for proper identification). Matsuura et al., 2018: 30–33 (comparison of M. fraserbrunneri with M. albomaculosus).
Material. Known from the holotype ANSP 103314, seven additional specimens, and two separate photographic records of individuals that were not retained (Table 1).
Diagnosis. A species of Mephisto with red to pink coloration and lighter, almost white, areas and darker red blotches; the ventral part of the head and body beginning under the eye is light in coloration, but no white, rounded markings are present (Fig. 1 A–D). Pelvic width 10.6–12.1% SL; pelvic width into pelvic length 2.6–3.2 times; gill rakers 16–19; pseudobranch lamellae 17–20.
Description. Data on meristics (Table 2), proportional measurements (Table 3), and additional characters (Table 4) are summarized for all eight specimens.
Coloration. Mephisto fraserbrunneri is red to pink with lighter, almost white, areas and darker red blotches (Fig. 1 A–D). The darkest red regions are below the spinous dorsal fin, below the posterior part of the soft dorsal fin, and above the pectoral fin from behind the eye. The ventral part of the head, beginning under the eye, is light in coloration. The spinous dorsal fin is predominantly dark red, whereas the soft dorsal and anal fins are white proximal to the body and darker distally. In alcohol, the blotchy pattern remains, and the darkest red areas in life are brown (Fig. 4A). The peritoneum and branchial cavity are tan to blackish and speckled with darker spots (Table 4).
Description of scales during ontogeny. The scales of Mephisto fraserbrunneri begin with a single spinule and increase in number of spinules during their ontogeny; the branching of spinules also increases with specimen length. Matsuura et al. (2018: fig 2) described the scales of M. albomaculosus as differing from those of M. fraserbrunneri because the scales of M. albomaculosus have a bifurcate spinule at the base of the central spinule (Fig. 5D). However, the new specimens reported herein increase the size range known for M. fraserbrunneri, and we now have more information on how the number of spinules and their branches change throughout ontogeny (Table 4). We confirm that large M. fraserbrunneri (DABFUK/FI/ 302, 102.7 mm SL and USNM 350153 105.8 mm SL) have up to six spinules per scale, with 1–3 branched spinules and the central and largest spinule having a bifurcate spinule at the base (Fig. 5). Thus, having a bifurcate spine on the central spinule is not diagnostic for Mephisto species. Shcherbachev et al. (1986) identified USNM 350153 as Mephisto sp. because at the time it was collected and examined only two small specimens of Mephisto fraserbrunneri were known, and each had scales with a single, unbranched spinule; we recognize the multiple spinule pattern present in the largest specimens as representing an advanced stage of ontogeny (Fig. 5 A–C).
Description of teeth and tooth replacement. Mephisto has relatively few stoutly conical teeth that are larger in the anterior part of the jaw and smaller posterolaterally on the premaxilla and dentary (Table 2; Fig. 6). Teeth are re- placed intraosseously (Fig. 6). Teeth develop underneath functional teeth and erupt on the labial side of the jaw. There is no obvious pattern of replacement; several teeth in the jaws of various specimens were in the process of replacement. For example, in the specimen shown in Figure 6, there are nine teeth in both the left and right premaxillae; two or three teeth are undergoing replacement (loci 3 and 7 in the left premaxilla; loci 1, 3, and 9 in the right premaxilla). On each side of the left and right dentary there are 11 teeth; two to four teeth are undergoing replacement (loci 2 and 10 on the left dentary and loci 1, 3, 7, and 9 on the right dentary). In the right dentary, locus 1 has an eroding tooth and an erupting replacement tooth beneath it.
Diet. Three specimens of Mephisto fraserbrunneri had stomach contents: DABFUK/FI/304 contained primarily foraminiferans and secondarily pteropods. Both planktic (Globorotalia menardii, Globigerinella siphonifera, Globigerinoides ruber, Neogloboquadrina dutertrei, and Trilobatus sacculifer) and benthic (Bolivina and Uvigerina) foraminiferans were present (Brian Huber, pers. comm., 2020). Pteropod shells, as well as several scaphopods and an echinoderm spine, were also in the stomach. The shells of these organisms had sediment on them, and the foraminiferans did not appear to have been ingested alive. USNM 306629 had well-digested amphipods in its stomach. The largest specimen, USNM 350153, had chitin fragments and peropods of a gammarid in its stomach (Gorelova et al., 1993), which were lost when it was cleared and stained. Based upon this data, we conclude that M. fraserbrunneri feeds on a diversity of small organisms found on or in bottom sediment.
Geographic and depth distribution. The holotype of Mephisto fraserbrunneri was collected in the Andaman Sea off Myanmar. Three of the eight known specimens of M. fraserbrunneri were collected off Somalia. The four most recently collected specimens of M. fraserbrunneri were caught off Kerala on the southwest coast of India in the Lakshadweep Sea (Fig. 2). All eight specimens of M. fraserbrunneri were caught in bottom trawls at depths of 176–415 m (Table 1).
description: Published as part of Bemis, Katherine E., Tyler, James C., Psomadakis, Peter N., Ferris, Lauren Newell & Kumar, Appukuttannair Biju, 2020, Review of the Indian Ocean spikefish genus Mephisto (Tetraodontiformes Triacanthodidae), pp. 82-98 in Zootaxa 4802 (1) on pages 90-94, DOI: 10.11646/zootaxa.4802.1.5, http://zenodo.org/record/3991949