Odontamblyopus rebecca , Edward O. Murdy & Koichi Shibukawa, 2003

Edward O. Murdy & Koichi Shibukawa, 2003, Odontamblyopus rebecca, a new species of amblyopine goby from Vietnam with a key to known species of the genus (Gobiidae: Amblyopinae)., Zootaxa 138, pp. 1-6: 2-6

publication ID

z00138p001

publication LSID

lsid:zoobank.org:pub:215F5561-93F2-4E75-AFF1-3F8817CCD88F

persistent identifier

http://treatment.plazi.org/id/B2E5396C-1B12-4AF9-8B19-9CAC129038AF

taxon LSID

lsid:zoobank.org:act:B2E5396C-1B12-4AF9-8B19-9CAC129038AF

treatment provided by

Thomas

scientific name

Odontamblyopus rebecca
status

sp. nov.

Odontamblyopus rebecca  ZBK  sp. nov.

(Fig.1; Tables 1-2)

Holotype: ROM 72279, 141.0 mm SL, male.GoogleMaps 

Paratypes: AMS I.41549-001, 2: 110.8-125.6 mm SL; MNHN 2002-3010, 1:78.5, MNHN 2002-3011, 1:89.0, MNHN 2002-3012, 1: 92.0 mm SL; ROM 72625, 2:96.1- 136.8 mm SL; ROM 72626, 26:75.1-132.6 mm SL; USNM 369736, 3:113.1-137.8 mm SL.GoogleMaps 

All material was collected on 29 February 2000 by Richard Winterbottom from a fish market located on the east side of Haiphong City   GoogleMaps, Vietnam (20º52' N, 106º41' E).

Diagnosis. Odontamblyopus rebecca  ZBK  can be diagnosed from congeners by the following combination of characters: total dorsal-fin elements 44-48 (mean 45.8), anal-fin elements37-42 (mean 38.5), pectoral fin with 40-51 rays (mean 45.8), and caudal vertebrae 20-21 (mean 20.1). A brownish streak courses from the dorsal surface of the head along dorsum to the caudal fin; chin blackish; caudal fin blackish.

Description. Counts of holotype given first, followed by those of paratypes in parentheses. D VI (VI), 40 (38-42), first non-spinous dorsal-fin ray segmented and branched; spinous dorsal-fin pterygiophore formula 3-12210 (holotype and all paratypes); dorsal fin connected by membrane to the caudal fin. Anal-fin rays 38 (37-42), first element of anal fin segmented but not branched. Anal fin connected by membrane to caudal fin. Pectoralfin rays 45/45 (40-51), all pectoral-fin rays segmented, occasionally one or more ventralmost rays branched, all others unbranched; for distal half of fin, membranous connection lacking so that rays are free and silk-like. Pelvic-fin rays I, 5; frenum present; interradial membrane uniting fins present throughout length of innermost rays. Caudal fin with 17 (17) segmented rays including 8+7 (8+7) branched rays and a dorsal and ventral simple ray.

Scales cycloid, embedded, non-imbricated, and difficult to discern without magnification; present on body and head, largest posteriorly. Head scales most abundant on dorsum with some scales on cheeks and a few on operculum. Two lateral rows of teeth in each jaw, more than two rows anteriorly; outer-row teeth much larger and more pointed than those of inner rows; lower-jaw teeth longer than upper-jaw teeth; 19 (7-20) fang-like teeth in outer row of upper jaw, typically interlocking with those of lower jaw; numerous conical teeth on inner rows of upper jaw; 9 (6-10) fang-like teeth in outer row of lower jaw; numerous conical teeth in inner rows of lower jaw. Two (occasionally only one) stout caninoid teeth internal to symphysis of lower jaw. No palatine or vomerine teeth present.

Precaudal vertebrae 10 (10), caudal vertebrae 20 (20-21).

Coloration. Head and body tannish brown. Chin with diffuse blackish blotch. Dorsal surface of head dusky brown as is dorsal-fin base almost to the caudal peduncle. From midpoint of caudal fin posteriad, blackish. Other fins translucent.

Distribution. Known only from a single locality, a fish market located on the east side of Haiphong City, Vietnam. The collector of these specimens, Dr. Richard Winterbottom, assumes the specimens were obtained along the Gulf of Tonkin coast, which is near the market, or in a nearby estuarine environment. Nguyên (1991) reported an unidentified species of Odontamblyopus  ZBK  from coastal provinces in northern Vietnam and stated that the species possessed: VI, 39-42 dorsal-fin rays; 37-41 anal-fin rays; 43-50 pectoral-fin rays; 10+19 (18-20) vertebrae. With the exception of the caudal vertebral count, we believe that Nguyên's description is a match with the subject specimens. (As we do not know Nguyên's methodology for counting vertebrae, we cannot be sure that our counting methods are the same.) Unfortunately, attempts to contact Mr. Nguyên were unsuccessful so his specimens were not available to us.

Etymology. This species is named for Rebecca Rootes, the life partner and spouse of the first author.

Comparisons with congeners. The following data and information pertaining to Odontamblyopus  ZBK  , excepting the new species described herein, were taken from Murdy and Shibukawa (2001) unless otherwise cited. With respect to O. rebecca  ZBK  , O. roseus  differs in having a chocolate-brown distal margin on the median fins (vs. translucent in O. rebecca  ZBK  ); more caudal vertebrae (22 in O. roseus  vs. typically 20 in O. rebecca  ZBK  ) and in having a longer pelvic fin (pelvic-fin length/SL 0.124-0.151, mean = 0.141, in O. roseus  vs. 0.074- 0.126, mean = 0.107, in O. rebecca  ZBK  ). In comparison to O. rubicundus  , O. rebecca  ZBK  has more caudal vertebrae (20-21 in O. rebecca  ZBK  vs. 17 in O. rubicundus  ); a longer pectoral fin with respect to head length (pectoral-fin length/head length 0.673-1.050, mean = 0.852, in O. rebecca  ZBK  vs. 0.628-0.965, mean = 0.719, in O. rubicundus  ); and fewer anal-fin pterygiophores anterior to the first hemal spine (typically 2 in O. rebecca  ZBK  vs. 3 in O. rubicundus  ). Whereas there is considerable overlap in most meristic values between O. rebecca  ZBK  and O. lacepedii  , a significant difference exists in the number of pectoral-fin rays (40-51, mean = 45.8, in O. rebecca  ZBK  vs. 24-33, mean = 27.9, in O. lacepedii  ). Several morphometric measures also serve to distinguish O. rebecca  ZBK  from O. lacepedii  : SL/TL (range 0.761-0.829, mean = 0.788, in O. rebecca  ZBK  vs. 0.808-0.850, mean = 0.825, in O. lacepedii  ); pelvic-fin length/head length (range 0.508-0.842, mean = 0.703, in O. rebecca  ZBK  vs. 0.665-1.08, mean = 0.810, in O. lacepedii  ); and pectoral-fin length/SL (range 0.093-0.154, mean = 0.130, in O. rebecca  ZBK  vs. 0.082-0.132, mean = 0.101, in O. lacepedii  ).

Within the genus Odontamblyopus  ZBK  , only O. tenuis  and O. rebecca  ZBK  have pectoral-fin ray counts greater than 39; the average pectoral-fin ray count for O. tenuis  is 59.5 (range = 46-65) whereas for O. rebecca  ZBK  it is 45.8 (range = 40-51). (No other species of Odontamblyopus  ZBK  has more than 33 pectoral-fin rays.) We hypothesize that the shared possession of high numbers of pectoral-fin rays connotes a greater degree of relatedness between these two species than with species that do not possess this feature.

In contrast with O. rebecca  ZBK  , O. tenuis  has barbels on the underside of the chin ( O. rebecca  ZBK  has none). O. tenuis  typically has fewer elements in both the dorsal and anal fins than does O. rebecca  ZBK  (range of dorsal-fin elements 40-42, mean = 40.4, in O. tenuis  vs. range of 44-48, mean = 45.8, in O. rebecca  ZBK  ; range of anal-fin elements 32-35, mean = 33.2, in O. tenuis  vs. range of 37-42, mean = 38.5, in O. rebecca  ZBK  ). O. tenuis  and O. rebecca  ZBK  differ in vertebral numbers; O. tenuis  has 17 caudal vertebrae whereas O. rebecca  ZBK  typically has 20. Epineurals are present from 1st precaudal vertebra to the 5th caudal vertebra in O. tenuis  , and 1st precaudal vertebra to the 4th, 5th, 6th, or 7th caudal vertebra in O. rebecca  ZBK  .

The following morphometric measures also show differences between the two species: head length/SL (range of 0.078-0.130, mean = 0.114, in O. tenuis  vs. 0.130-0.179, mean = 0.152, in O. rebecca  ZBK  ); head width/SL (0.040-0.059, mean = 0.054, in O. tenuis  vs. 0.062- 0.110, mean = 0.083, in O. rebecca  ZBK  ); and pectoral-fin length/SL (0.084-0.119, mean = 0.102, in O. tenuis  vs. 0.093-0.154, mean = 0.130, in O. rebecca  ZBK  ).

Key to the species of Odontamblyopus  ZBK 

(modified from Murdy and Shibukawa, 2001)

1a. Pectoral-fin rays 40 or more .......................................................................................... 2

1b. Pectoral-fin rays 33 or fewer ......................................................................................... 3

2a. Chin with numerous small barbels; pectoral-fin rays 46-65; total dorsal-fin elements 40-42; anal-fin elements 32-35; 17 caudal vertebrae. (Pakistan, Myanmar) .... O. tenuis 

2b. Chin lacking barbels; pectoral-fin rays 40-51; total dorsal-fin elements 44-48; anal-fin elements 37-42; 20-21 caudal vertebrae. (Vietnam) ........................ O. rebecca  ZBK  sp. nov.

3a. In preservative, distal margins of dorsal and anal fins tinged chocolate-brown; dorsal surface of skull bony lacking portions of adductor mandibulae muscle; epineurals present from 1st precaudal vertebra to 10th caudal vertebra. (west coast of India) .......... .......................................................................................................................... O. roseus 

3b. In preservative, distal margins of dorsal and anal fins the same color as rest of fin but not chocolate-brown; dorsal surface of skull covered by adductor mandibulae muscle; epineurals present from 1st precaudal vertebra to 3rd, 4th, or 5th caudal vertebra ............ 4

4a. Caudal fin very long, standard length typically less than 80% of total length; total dorsal-fin elements 40-47; anal-fin elements 33-40; caudal vertebrae 17; 3 anal-fin pterygiophores preceding first hemal spine. (east coast of India, Bangladesh, Myanmar) .... .................................................................................................................. O. rubicundus 

4b. Caudal fin long, standard length more than 80% of total length; total dorsal-fin elements44-54; anal-fin elements 36-45; caudal vertebrae 20-24; 2 (rarely 3) anal-fin pterygiophores preceding first hemal spine. (China, Hong Kong, Taiwan, Korea, Japan) ...................................................................................................................... O. lacepedii 

ROM

Canada Entomology Department, Royal Ontario Museum

AMS

Australia, New South Wales, Sydney, Australian Museum

MNHN

France, Paris, Museum National d'Histoire Naturelle

USNM

USA, Washington D.C., National Museum of Natural History, [formerly, United States National Museum]