Echiodon prionodon, Parmentier, 2012

Parmentier, Eric, 2012, Echiodon prionodon, a new species of Carapidae (Pisces, Ophidiiformes) from New Zealand, European Journal of Taxonomy 31, pp. 1-8 : 3-6

Echiodon prionodon sp. nov.

urn:lsid:zoobank.org:act:44A01315-F569-4553-B342-69C5D1C51ACF

Figs 1-4

Diagnosis

A species of Echiodon , with a serrated posterior margin on the fangs, expanded thoracic plates on some abdominal vertebrae, PCV 33–35, D 30 42–45, A 30 40–41.

Etymology

From the Greek priôn meaning saw, and odous (odon) meaning tooth, in reference to the unique morphology of the fang at the tip of the jaw.

Type material

Holotype

Ƌ, 165 mm TL, in NMNZ (P.041833), RV Tangaroa , sta. TAN 0413/119, 13 Nov. 2004.

Paratypes

NMNZ P.003281 (97 mm TL), off Kapiti Island, 40°51.0’S – 174°52.0’E, Fred Abernethy, 37 m, Apr. 1958, badly cleared and stained specimen; NMNZ P.052493 (57+ mm, anterior portion only), outer North Taranaki Bight, RV Tangaroa , sta. TAN 1105/137, 38°26.70’S – 173°18.97’E, 170-240 m epibenthic sled, 5 Apr. 2011.

Type locality

Off White Island, outer Bay of Plenty, New Zealand, 37° 33.57’S – 176° 59.1-58.8’E, 313 m bottom trawl.

Description

Selected counts and measurements are given in Table 1 and the holotype is shown in Figure 1 . Body slender, much higher than wide, tapering into a pointed tail; greatest body depth (at anus) approximately 5% of total length; no caudal fin; dorsal fin origin posterior to anal fin origin, anus ends in a tube at half length of the pectoral fin. Dorsal profile of head slightly convex. Snout rounded in lateral view, slightly projecting beyond upper jaw. Olfactory lobe approximately 70% of snout length, closer to the eye than to the snout tip; anterior nostril developed in a small tube; posterior nostril directly in front of anterior margin of eye, elliptical, being higher than long. Eye elongate, longer than high. Mouth oblique, upper jaw extending beyond posterior margin of eye; posterior portion of maxilla unsheathed. Anterior tip of lower jaw behind tip of snout, lower jaw occlusion with palatine bones. Short opercular spine exposed through an elliptical slit in skin. Gill opening extends from upper end of pectoral fin base to below rear end of maxillary. Seven branchiostegal rays. Ceratobranchials 1 with three slender gill-rakers, with tooth pads on upper limb; other gill-rakers tubercular.

Two enlarged caniniform teeth near symphysis in premaxilla and in dentary (one tooth missing on left lower jaw in holotype). Each of these caniniform teeth has a serrated margin posteriorly ( Fig. 2 ). Upper and lower jaw fangs are separated from the posterior teeth rows by a pronounced diastema. Eight to nine rows of small, minute, straight, conical teeth on dentary, 3-4 outer rows with smaller teeth. Four to five rows of small conical teeth on the upper jaw, teeth on inner rows somewhat longer and curved inwardly, teeth of outer rows similar to lower jaw teeth. Palatine with 4-5 rows of villiform teeth. Vomer a small oblong bump with irregular disposition of small conical teeth, posterior one being somewhat bigger. In the holotype ( Fig. 3 ), vertebral centra 6 to 24 with parapophyses expanded to form lateral plates (vertebral centra 6 to 14 in NMNZ P. 052493, 6 to 17 in NMNZ P.003281). Holotype swimbladder extends to 30 th vertebral centra (57.9 mm from the snout tip), slight central constriction separating anterior part, brown with dark spots, and shorter posterior part, unpigmented and with ventral tunic ridges.

Color pattern

After eight years in alcohol, the holotype has cream-colored body and head. Melanophores highly concentrated at the level of the geniohyoideus (throat), but not on the lower jaws, at the oro-branchial cavity on the tongue, the palate, branchial arches, on the inner face of the opercula, on the parietals and on the posterior parts of the frontal. Stomach and peritoneal cavity black, anus unpigmented. Melanophores concentrated at the base of dorsal and anal fins and forming lines on the lateral lines and on different myosepta. Pterygiophores of anal and dorsal fins black from the tip to approximately 1/5 of the body length.

Differential diagnosis

Echiodon prionodon sp. nov. is unique in having serrated posterior margin on the fangs. Moreover, it differs from all others Echiodon species by the thoracic plates on some abdominal vertebrae and it differs from Eurypleuron species by having tunic ridges on the swimbladder.

Distribution

Endemic to coastal waters around the North Island of New Zealand ( Fig. 4 ). The species seems to be benthic from 30 to 315 m depth. The holotype was caught along with other fish species which usually are associated with shelly-gravel to sandy bottoms with patch reefs as Gnathophis umbrellabius (Whitley, 1948) (Congridae) , Hoplostethus mediterraneus Cuvier, 1829 (Trachichthyidae) and Paraulopus nigripinnis (Günther, 1878) (Paraulopidae) .

Figures

Fig 1. Echiodon prionodon sp. nov., left lateral view (holotype NMNZ P.041833, 165 mm TL).

Fig. 2. Echiodon prionodon sp. nov., left lateral view of the left premaxillary fang showing the posterior serrated margin.

Fig. 3. Echiodon prionodon sp. nov., left lateral X-ray (holotype NMNZ P.041833, 165 mm TL).

Fig. 4. Distribution of Echiodon prionodon. The red circle depicts the locality where the holotype was caught.

Tables

Table 1. Morphometric (mm) and meristic data for Echiodon prionodon sp. nov. Numbers in brackets refer to measurements in % head length.

	NMNZ P. 041833 Holotype	NMNZ P.003281 Paratype	NMNZ P. 052493 Paratype
Total length (mm)	165	97	-
Head length	17.8	12.8	12.5
Preanus length	21.1 (118)	14.9 (116)	15.4 (123)
Predorsal length	26.3 (147)	15.8 (123)	17.8 (142)
Snout length	2.5 (14)	2.0 (15)	2.2 (17)
Upper jaw length	7.8 (44)	5.9 (46)	6.0 (48)
Lower jaw length	9.3 (52)	6.4 (49)	6.8 (54)
Horizontal eye diameter	4.1 (23)	3.3 (25)	2.9 (23)
Head depth	6.9 (39)	5.3 (41)	-
Depth at anus	8.4 (47)	5.8 (45)	6.3 (50)
Interorbital length	2.2 (12)	1.4 (11)	1.5 (12)
Pectoral length	8.7 (49)	-	8.2 (65)
Meristic
PCV	33	33	35
D 30 A 30 VDO	45	42	-
	40	-	41
	8	8	8
VAO	7	6	7
VPB	7	-	7
P 1	15	14	13