Principal Caudal Rays Research Articles

Two new species of snailfishes of the genus emCareproctus/em (Cottoidei: Liparidae) from the western North Pacific Ocean with a range extension of emCareproctus brevipectoralis/em.

Three snailfish species of Careproctus (Cottoidei: Liparidae), including two new species, are described from the deep Pacific Ocean off northern Honshu Island, Japan. Careproctus cyanogladius sp. nov., collected from the depths of 2,698-3,223 m, can be distinguished from congeneric species by having the following combination of characters: vertebrae 63; dorsal-fin rays 57-58; anal-fin rays 50; principal caudal rays 7; pectoral-fin rays 29-31; pectoral fin without a notch; uppermost pectoral-fin base below a horizontal through posterior margin of maxillary; pelvic disk oval; chin pores well separated; teeth simple; pyloric caeca 6-10; body pale blue or gray when fresh. The other new species, Careproctus orri sp. nov., collected from depths of 640-808 m, can be distinguished from congeneric species by having the following combination of characters: vertebrae 58-60; dorsal-fin rays 52-53; anal-fin rays 47-49; pectoral-fin rays 34-35; pectoral fin with a distinct notch; cephalic pores 2-6-7-2, chin pores single, unpaired; gill slit extending ventrally to 5th or 6th pectoral-fin ray; teeth strongly trilobed; peritoneum dark, stomach white. In addition, one specimen of Careproctus brevipectoralis Chernova, Thiel Eidus, 2020 was newly collected from Japan, and is redescribed here in detail with comments on intraspecific variations.

Osteology of the posterior vertebral column and caudal skeleton of marine amphibious gobies (mudskippers) (Teleostei: Gobioidei)

Mudskippers are amphibious gobies (Teleostei: Gobioidei, Oxudercinae) that have served as models for the specialised physiology and behaviour of fishes out of water. In this study, a comparative analysis of the posterior vertebral column and the caudal skeleton of ten mudskipper species was conducted on the basis of X-ray imaging. The species considered were Apocryptes bato, Apocryptodon madurensis, Boleophthalmus dussumieri, Oxuderces dentatus, Periophthalmodon freycineti, Pn. schlosseri, Periophthalmus novemradiatus, Ps. waltoni, Pseudapocryptes borneensis, and Scartelaos tenuis. For the osteological description the new term 'modified caudal vertebra' is used for all those vertebrae that display visibly modified neural and/or haemal spines compared to the spines of a 'usual' caudal vertebra, but are not involved in the support of caudal rays. The results reveal that the most terrestrial forms (Pn. freycineti, Pn. schlosseri, Ps. novemradiatus, Ps. waltoni) possess distinct traits that are seldom found in the other species. Among these features are (a) the existence of at least two modified caudal vertebrae (also present in S. tenuis), (b) a particularly close, dovetailing association between the neural spines of the preural vertebrae two and three (restricted to Ps. novemradiatus and Ps. waltoni), and (c) thickening and shortening of the ventralmost principal caudal rays (also present in B. dussumieri and S. tenuis). These findings support the idea that the posterior caudal vertebrae and caudal skeleton of the mentioned species are modified to enhance locomotion on land. Moreover, a relationship between character development and degree of terrestrial adaptation is probable, as all three traits are most pronounced in Ps. waltoni, which correlates with its strikingly high level of adaptation to amphibious life. A further aspect of this study is that the newly recognized skeletal structures have good fossilization potential and could therefore facilitate recognition of fossil species of mudskippers, which are currently unknown.

A Fossil Melamphaid Fish of the Genus Scopelogadus (Teleostei: Melamphaidae) from the Neogene Deposits of Sakhalin Island, Russia

The skeleton of a berycomorph fish of the Melamphaidae family was found in sediments of the Middle-Upper Miocene of the Kurasi Formation of Sakhalin Island, Russia. Morphological features, such as a short tall body with a large head, the presence of one dorsal fin with a short base, 19 principal caudal rays, a small number of vertebrae, and single-row jaw teeth in combination with very large cycloid scales enable the assignment of this fossil to the modern genus Scopelogadus. This is the second known record of a fossil skeleton for both the genus Scopelogadus and the family Melamphaidae. The fossil locality is placed approximately 17 degrees north of the range of extant species of the genus. The presence of scopelogadus fish in the Kurasi Formation complex suggests that the accumulation depth of its deposits was at least 200 m.

Different levels of amphibious adaptation in three mudskipper species from the Persian Gulf: Insights from skeleton and otolith characteristics

Event Abstract Back to Event Different levels of amphibious adaptation in three mudskipper species from the Persian Gulf: Insights from skeleton and otolith characteristics Mehdi Ghanbarifardi1, Carolin Gut2, Zeinab Gholami2, Hamid Reza Esmaeili3, Christoph Gierl2 and Bettina Reichenbacher2* 1 University of Sistan and Baluchestan, Department of Biology, Faculty of Sciences, Iran 2 Ludwig Maximilian University of Munich, Department of Earth and Environmental Sciences, Palaeontology and Geobiology, Germany 3 Shiraz University, Department of Biology, College of Sciences, Iran Mudskippers are amphibious gobies (Teleostei: Gobioidei) that have served as models for the specialised physiology and behaviour of fishes out of water. Here we present new data on the skeletons and otoliths of three endemic mudskipper species from the Persian Gulf, i.e. Boleophthalmus dussumieri, Scartelaos tenuis and Periophthalmus waltoni, supplemented by one specimen each of Periophthalmodon schlosseri and Pn. freycineti from a museum collection. The species investigated are known for their different levels of amphibious adaptation, which allowed us to examine whether their skeletal and otolith characters might also reflect associated functional constraints. Based on X-ray and SEM imaging, we show here that the five species studied share three exceptional characters. One concerns the principal caudal rays, one relates to the caudal endoskeleton, and one to the otolith. A relationship between character innovation and degree of amphibious adaptation can be suggested for two of these traits. Our data also reveal that the Periophthalmodon and Periophthalmus species have three further exceptional characters of the caudal endoskeleton in common. Moreover, three additional unique traits, two related to the caudal endoskeleton and one to the otolith, were identified in Ps. waltoni. Following previous work on mudskipper locomotion, we suggest that the particular traits of the principal caudal rays and caudal endoskeleton developed in response to the extra stresses imposed on the tail when the fish moves about on land or is performing terrestrial jumps (skipping). The unique characters related to the otoliths may be linked to specialization in intraspecific acoustic communication via the wet substratum of emerged mudflats, but further work is needed to support this assumption. Our new data may also facilitate recognition of fossil species of mudskippers – which are currently unknown – as both skeletons and otoliths have good fossilization potential. Keywords: Amphibious goby, Terrestrial adaptation, caudal fin and skeleton, Osteology, Otolith morphology Conference: XVI European Congress of Ichthyology, Lausanne, Switzerland, 2 Sep - 6 Sep, 2019. Presentation Type: Oral Topic: MORPHOLOGY, ONTOGENY AND PALAEONTOLOGY Citation: Ghanbarifardi M, Gut C, Gholami Z, Esmaeili H, Gierl C and Reichenbacher B (2019). Different levels of amphibious adaptation in three mudskipper species from the Persian Gulf: Insights from skeleton and otolith characteristics. Front. Mar. Sci. Conference Abstract: XVI European Congress of Ichthyology. doi: 10.3389/conf.fmars.2019.07.00076 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 30 May 2019; Published Online: 14 Aug 2019. * Correspondence: Mx. Bettina Reichenbacher, Ludwig Maximilian University of Munich, Department of Earth and Environmental Sciences, Palaeontology and Geobiology, Munich, Bavaria, 80802, Germany, b.reichenbacher@lrz.uni-muenchen.de Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Mehdi Ghanbarifardi Carolin Gut Zeinab Gholami Hamid Reza Esmaeili Christoph Gierl Bettina Reichenbacher Google Mehdi Ghanbarifardi Carolin Gut Zeinab Gholami Hamid Reza Esmaeili Christoph Gierl Bettina Reichenbacher Google Scholar Mehdi Ghanbarifardi Carolin Gut Zeinab Gholami Hamid Reza Esmaeili Christoph Gierl Bettina Reichenbacher PubMed Mehdi Ghanbarifardi Carolin Gut Zeinab Gholami Hamid Reza Esmaeili Christoph Gierl Bettina Reichenbacher Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

A new species of cardinalfish (Gymnapogon, Gymnapogonini, Apogonidae, Percomorpha) from the Philippines.

The new species is consistent with Gymnapogon, a distinct genus having one to three spines on the preopercle edge, fused hypurals (parhypural+1+2 and 3+4+terminal central), a free fifth hypural, two epurals, no supraneurals, scaleless head and body, a single rod-like postcleithrum and complex lines of free neuromasts on the head, body and caudal fin. The new species is distinguished by having a combination of a rounded caudal with 15 branched principal caudal-fin rays, 2 unbranched principal caudal-fin rays, 10 soft dorsal rays with the anterior two rays unbranched, 9 or 10 anal rays with the first ray unbranched and 14 pectoral rays the lower three and upper two unbranched. Nominal species Gymnapogon annona, G. foraminosus, G. japonicus, G. urospilotus and G. vanderbilti have 9 or 10 soft dorsal, 9 or 10 anal rays and 12 to 14 pectoral rays, the lower two and upper two unbranched. Gymnapogon africanus, G. melanogaster and G. philippinus have 9 soft dorsal rays, the first ray unbranched and 8 soft anal rays, the first ray branched. Gymnapogon japonicus has a rounded caudal fin with 13, 14 or 15 branched principal caudal rays. Gymnapogon africanus, G. annona, G. melanogaster, G. philippinus, G. urospilotus and G. vanderbilti have a forked caudal fin with 13 branched principal caudal rays and 2 unbranched upper and lower principal caudal rays. A single preopercle spine distinguishes the new species from the single bifid-like preopercle spine shared by Gymnapogon annona, G. melanogaster and undescribed forms. The wide-spread B-marked species complex made up of Gymnapogon urospilotus, G. vanderbilti and undescribed forms have at least one small upper preopercle spine in addition to the larger single spine near the angle of the preopercle.

Paranursallia spinosan. gen., n. sp., a new Upper Cretaceous pycnodontiform fish from the Eurafrican Mesogea

The osteology of the fossil fish Paranursallia spinosa n. gen., n. sp., from the marine Upper Cenomanian of Tunisia, is studied in details. The new species belongs to the family Pycnodontidae and the subfamily Nursalliinae. It is closely allied to “Nursallia” gutturosa (Arambourg, 1954), a species from the Cenomanian of Morocco, but differs from it by some cranial characters, by the lesser number of scutes in the dorsal ridge and the ventral keel and by the lesser number of principal caudal rays. Paranursallia spinosa n. gen., n. sp. differs more markedly from Nursallia veronae Blot, 1987 (Middle Eocene, Italy), the type-species of the genus Nursallia Blot, 1987, and from Nursallia tethysensis Capasso, Abi Saad & Taverne, 2009 (Cenomanian, Lebanon). It is proposed to include “Nursallia” gutturosa in the new genus Paranursallia n. gen.

Psilorhynchus khopai, a new fish species (Teleostei: Psilorhynchidae) from Mizoram, northeastern India.

Psilorhynchus khopai, a new species of Psilorhynchidae, is described from Tuisi River, a tributary of Kaladan River, in Mizoram, India. The species is proposed to be a member of the Psilorhynchus homaloptera species group and can be distinguished from its congeners in having a forked caudal-fin with 9 + 9 principal caudal rays, 14-17 predorsal scale rows, 39-41 lateral-line scale rows, mid-lateral body with 9-12 indistinct small dark brown round markings forming a lateral stripe and, in life, a faint gold stripe along dorsal midline with 4-5 black spots between dorsal fin and caudal fin base.

Revalidation and redescription of Pterocryptis anomala (Herre, 1933), a catfish (Teleostei: Siluridae) from southern China

Pterocryptis anomala (Herre, 1933) is resurrected from synonymy with P. cochinchinensis (Valenciennes, 1839) and redescribed in this study. This species of catfish from southern China and Hong Kong Special Administrative Region can be distinguished from congeners by the unique combination of the following characters: length of dorsal fin 7.9–10.1% SL, depth of caudal peduncle 7.2–9.7% SL, head length 16.6–20.7% SL, eye diameter 9.2–13.7% SL, dorsal-fin rays 3– 4, anal-fin rays 59–69, principal caudal rays 14–16, small conical genital papilla in both sexes, anal and caudal fins separated by a deep notch, narrow cheeks, circular eye and weakly contrasting mottled coloration. Characters for diagnosing Pterocryptis species are identified and discussed.

Reexamination of Bregmaceros lanceolatus Shen, 1960 with description of a new species Bregmaceros pseudolanceolatus (Gadiformes: Bregmacerotidae)

Based on our reexamination of the 9 specimens including the neotype, Bregmaceros lanceolatus is recharacterized and diagnosed by the following combination of features: caudal fin rounded; scales present on gill cover; dorsal surface of snout unpigmented or with a few chromatophores; isthmus pigmented with punctate chromatophores; two parapophyses on abdominal vertebrae; dorsal rays (D) 65–74; anal rays (A) 67–74; vertebrae (V) 58–61; longitudinal scales (LS) ca. 82–88; principal caudal rays (PC) 16–18; head length (HL)/standard length (SL) 14.0–15.5%; caudal peduncle depth/SL 3.2–4.2%. Based on 27 specimens, B. pseudolanceolatus sp. nov. is described. This species is closely similar to B. lanceolatus, but is diagnosed by the following combination of features: caudal fin rounded; scales present on gill cover; dense concentration of chromatophores on dorsal surface of snout; isthmus colorless; one board-like parapophysis on the last three abdominal vertebrae; D 58–64; A 58–67; V 52–55; LS ca. 68–77; PC 14–16; HL 15.5–18.4% SL; caudal peduncle depth 4.1–5.2% SL. Bregmaceros pseudolanceolatus is known from around the Taiwan Strait, southern East China Sea, South China Sea, Gulf of Thailand, Timor Sea, Arafura Sea, and eastern Bay of Bengal.

Larvae of Enchelyurus ater (Günther, 1877) and E. kraussi (Klunzinger, 1871) (Pisces: Blenniidae: Omobranchini)

The omobranchinin blenniid, Enchelyurus ater, ranges across the islands of the south Pacific Ocean, and E. kraussi ranges from the Red Sea to the Mariana Islands and eastern Australia. The planktonic larvae of these blennies were identified by establishing developmental series up to large larvae identifiable to species using morphological and meristic characters and geographic location. Larvae of both species are similar in appearance, hatch at about 1.5-2.5 mm length, and undergo notochord flexion at about 4.5-5.5 mm. Enchelyurus ater probably is near 12 mm, and E. kraussi probably nearer 15 mm, at settlement from the plankton. Larvae of both species have a rounded head, a short, coiled gut, an elongate, compressed tail, and about 34 myomeres. Small spines are present on the posterior preopercular margin at, or soon after, hatching. The spine at the preopercular angle becomes largest, reaching about 25% of head length in the postflexion stage. First the pectoral-fin rays, then principal caudal-fin rays, dorsal- and anal-fin anlagen, and pelvic-fin buds begin to form during the preflexion stage. All principal caudal rays are present by the end of the flexion stage. Pelvic-fin rays and all segmented dorsal- and anal-fin rays are present by mid-postflexion stage. Dorsal-fin spines and procurrent caudal-fin rays form during the postflexion stage. Larvae of both species initially are pigmented dorsally on the head and gut, posteriorly on the ventral margin of the tail, and on the mesial surface of the pectoral-fin base. Pigmentation gradually increases on the head and gut in both and on the pectoral fin in E. kraussi, and decreases on the ventral margin of the tail in both. Enchelyurus ater, E. kraussi, and the Hawaiian endemic, E. brunneolus, are a monophyletic group with unknown sister-species relationships. Larval characters suggest the hypothesis that E. ater is the sister species to E. brunneolus, and E. kraussi is the sister species to the other two.

The principal caudal fin ray count ‐ a fundamental character in the galaxioid fishes

The principal caudal rays, usually defined as the two largest segmented unbranched fin rays in the caudal fin that lie above and below, and the segmented branched caudal rays that they enclose, have a consistent relationship to the caudal skeleton in galaxioid fishes, being those fin rays supported by the primitively ventral surface of elements in the caudal skeleton. They comprise rays supported by skeletal elements including, and posterior to, the parhypural and hypurals. The most anterior (or ventral) principal ray is supported by the parhypural while the posterior (or uppermost) principal ray lies immediately below the point at which the notochord emerges from the truncated posterior end of the last caudal vertebra. The consistent relationship to these skeletal elements suggests that the principal caudal fin ray count is a character of fundamental nature for the galaxioid fishes, giving it particular phylogenetic significance in that group.

Caudal Skeleton in Galaxias and Allied Genera (Teleostei: Galaxiidae)

The caudal skeleton of galaxiid fishes typically comprises a composite main ural centrum (PUI + Ul), an additional small ural centrum U2, a parhypural and five separate hypurals, one epural and two uroneurals; caudal neural and haemal spines are usually broadly flattened. However, there is wide variation within and among species in various of these basic details, including fusion/loss of ural centrum U2; varied fusion of hypural elements; loss of flattening in caudal neural and haemal spines; variation in number of neural arches and form of neural spines on caudal vertebrae; even the number of parhypurals varies. An opisthural is present, defining the upper limits of the principal caudal rays which typically number 16.

A new primitive acanthomorph fish from the Greenhorn Formation (Late Cretaceous) of Nebraska

ABSTRACT A new acanthomorph genus is described from the Greenhorn Formation (Turonian) of north eastern Nebraska. The type and only specimen of this genus is a nearly complete skull and postcranial skeleton characterized by an interesting combination of features such as a prominent, anteriorly thickened supraoccipital crest, protrusile upper jaw with well developed premaxilla, opercular bones without spines, 39 vertebral centra, pectorals very low on the flank, pelvic fins in abdominal position, medial pelvic process distally ossified, true dorsal fin-spines present, and spinoid scales covering the trunk. The Late Cretaceous acanthomorph †Aipichthys shares a few characters with the new genus including deeply cleft caudal fin and nine principal caudal rays on the upper lobe of the caudal fin. Characters are shared also with †Araripichthys from the Early Cretaceous of Brazil. The material described resembles in certain characters (e.g., supraneurals, abdominal vertebrae and probably paired fin placement) the acanthomorph †Ferrifrons rugosus, represented by a single incomplete specimen from the Niobrara Chalk (Santonian). Based on a few synapomorphies, the new genus and †Ferrifrons are included in the new fossil family Ferrifronsidae.

Reevaluation of the caudal skeleton of certain actinopterygian fishes: III. Salmonidae. Homologization of caudal skeletal structures.

The ontogenetic development of caudal vertebrae and associated skeletal elements of salmonids provides information about sequence of ossification and origin of bones that can be considered as a model for other teleosts. The ossification of elements forming the caudal skeleton follows the same sequence, independent of size and age at first appearance. Dermal bones like principal caudal rays ossify earlier than chondral bones; among dermal bones, the middle principal caudal rays ossify before the ventral and dorsal ones. Among chondral bones, the ventral hypural 1 and parhypural ossify first, followed by hypural 2 and by the ventral spine of preural centrum 2. The ossification of the dorsal chondral elements starts later than that of ventral ones. Three elements participate in the formation of a caudal vertebra: paired basidorsal and basiventral arcocentra, chordacentrum, and autocentrum; appearance of cartilaginous arcocentra precedes that of the mineralized basiventral chordacentrum, and that of the perichordal ossification of the autocentrum. Each ural centrum is mainly formed by arcocentral and chordacentrum. The autocentrum is irregularly present or absent. Some ural centra are formed only by a chordacentrum. This pattern of vertebral formation characterizes basal teleosts and primitive extant teleosts such as elopomorphs, osteoglossomorphs, and salmonids. The diural caudal skeleton is redefined as having two independent ural chordacentra plus their arcocentra, or two ural chordacentra plus their autocentra and arococentra, or only two ural chordacentra. A polyural caudal skeleton is identified by more than two ural centra, variably formed as given for the diural condition. The two ural centra of primitive teleosts may result from early fusion of ural centra 1 and 2 and of ural centra 3 and 4, or 3, 4, and 5 (e.g., elopomorphs), respectively. The two centra may corespond to ural centrum 2 and 4 only (e.g., salmonids). Additionally, ural centra 1 and 3 may be lost during the evolution of teleosts. Additional ural centra form late in ontogeny in advanced salmonids, resulting in a secondary polyural caudal skeleton. The hypural, which is a haemal spine of a ural centrum, results by growth and ossification of a single basiventral ural arococentrum and its haemal spine. The proximal part of the hypural always includes part of the ventral ural arcocentrum. The uroneural is a modification of a ural neural arch, which is demonstrated by a cartilaginous precursor. The stegural of salmonids and esocids originates from only one paired cartilaginous dorsal arcocentrum that grows anteriorly by a perichondral basal ossification and an anterodorsal membranous ossification. The true epurals of teleosts are detached neural spines of preural and ural neural arches as shown by developmental series; they are homologous to the neural spines of anterior vertebrae. Free epurals without any indication of connection with the dorsal arococentra are considered herein as an advanced state of the epural. Caudal distal radials originate from the cartilaginous distal portion of neural and haemal spines of preural and ural (epurals and hypurals) vertebrae. Therefore, they result from distal growth of the cartilaginous spines and hypurals. Cartilaginous plates that support rays are the result of modifications of the plates of connective tissue at the posterior end of hypurals (e.g., between hypurals 2 and 3 in salmonids) and first preural haemal spines, or from the distal growth of cartilaginous spines (e.g., epural plates in Thymallus). Among salmonids, conditions of the caudal skeleton such as the progressive loss of cartilaginous portions of the arcocentra, the progressive fusion between the perichondral ossification of arcocentra and autocentra, the broadening of the neural spines, the enlargement and interdigitation of the stegural, and other features provide evidence that Prosopium and Thymallus are the most primitive, and that Oncorhynchus and Salmo are the most advanced salmonids respectively. This interpretation supports the current hypothesis of phylogenetic relationships of salmonids. © 1992 Wiley-Liss, Inc.

Synopsis of the whalefishes (family Cetomimidae) with descriptions of four new genera

This study of more than 500 specimens recognises two cetomimid subfamilies (one newly described), nine genera (four newly described) and about 35 species (four newly described). Characters of the gill arches, head laterosensory canals, lateral line scales, cavernous tissue, anal lappets and subpectoral organ (the last three of unknown function) are used to distinguish taxa. A cladistic analysis of 39 characters utilised Rondeletia and Barbourisia as outgroups to polarise character states within the family and the beryciform families to polarise family characters. Three synapomorphies, the presence of gill rakers in some form other than elongate and flattened and the absence of pelvic fins and pleural ribs, support the monophyly of the family. The monotypic Procetichthyinae, defined by four autapomorphies, is the primitive sister group of all other cetomimids. It retains such pleisiomorphic features as a fully developed nasal organ, a fully developed eye with lens, a pseudobranch and 19 principal caudal rays. Ditropichthys is the primitive sister group of the remaining seven genera, with the next line including the related Cetichthys and Notocetichthys. The relationships of the remaining five genera are equivocal, except that Cetomimus and Gyrinomimus are sister taxa defined by lateral line scale shape. A working hypothesis of relationships is presented that places Danacetichthys and Cetostoma as sister groups of the remaining three genera. Multistate characters of gill raker-tooth plate shape and extent of the fourth gill slit support the hypothesis. Cetostoma and Rhamphocetichthys are highly derivative forms, with each monotypic genus defined by three or four autapomorphies. The genera Gyrinomimus and Cetomimus each have more than ten species, which will be reviewed in later papers. The other genera each have one or two species that are fully detailed here. All examined specimens with recognisable gonads are females, confirmed by histology of eight specimens representing four genera. Egg sizes of at least 2.0, 1.3 and 0.6 mm diameter are attained by the genera Procetichthys, Gyrinomimus and Cetostoma respectively. The vast majority of examined specimens had eggs 0.1 mm diameter or less. The few specimens with larger eggs had bimodal egg sizes. Males and individuals less than 25 mm are unknown. Maximum size is at least 390 mm in one species of Gyrinomimus, while Ditropichthys and Cetostoma apparently do not exceed 140 mm and 250 mm, respectively. Crustaceans are the primary food of whalefishes. The family is distributed in all oceans, from 52°N to 72°S. At the species level, two distribution patterns are apparent. The two commonest species, Cetostoma regani and Ditropichthys storeri, have cosmopolitan distributions between 50°N and 40°S. The two most frequently captured species of Gyrinomimus are restricted to the north Pacific between 39° and 52°N and circumglobally in the Southern Ocean between 32° and 72°S. There are too few collections of the other species to ascertain distributional limits, but some have been taken in all three oceans and others only in a part of one ocean. The centres of vertical distribution for all species are below 1000 m. Only smaller specimens of C. regani and D. storeri have been taken above 1000 m, where some nocturnal vertical migration is indicated. Closing net captures confirm large specimens of both species live between 1200 and 1500 m. Four separate closing net captures of Cetichthys parini between 2700 and 3200 m demonstrate this to be the deepest living known whalefish. At least some cetomimids are more abundant than previously thought, with 55% of the ISH midwater trawls in the Atlantic fishing to 1800 m or deeper catching whalefishes. Up to 11 specimens and six different species of whalefishes were taken in a single deep trawl. With about 35 species, cetomimids are second only to the anglerfish family Oneirodidae as the most speciose bathypelagic fish family and may be the most abundant below 1800 m. As four of the eight species considered in this paper are represented by less than five specimens, it seems probable that additional species of cetomimids will be captured.

Osteological development of the lophiid anglerfish,lophius gastrophysus

The osteological development of the head skeleton and dorsal, pectoral, and anal fin supports, are described from cleared and stained specimens ofLophius gastrophysus larvae, ranging from 4.6 to 21.8 mm NL; the results are compared with those of juvenile (79.8 mm SL) and adult (398 mm SL) specimens. Tiny conical teeth are present on the premaxillary, dentary, palatine and vomer since early stage. The first three dorsal fin spines are initially positioned on the midline of body posterior to the supraoccipital, but they migrate forward with growth and become cephalic in juveniles. The forward movement of the dorsal spines is produced by the forward extension of the cartilaginous basal inside the subepidermal space. During the planktonic larval stage the pectoral fins are on the sides of body as in ordinary fishes, but they move ventrad and become leg-like in bottom living juveniles and adults. Ossification of the caudal complex ofL. gastrophysus larvae proceeds very slowly and only the 21.8 mm NL larva has an almost completely ossified caudal complex. Eight principal caudal rays are loosely attached on the posterior edge of the hypurals and no procurrent rays are present. Larvae have well developed parhypurapophysis at the mid-portion of the urostyle which transforms into keel-like structure in juveniles and adults.

Another New Species of the Clingfish Genus Derilissus from the Western Atlantic (Pisces: Gobiesocidae)

new genus and species of clingfish, Derilissus nanus, from the Bahama Islands. Subsequently, Fraser (1970) described two additional new species of Derilissus and utilized several generic characters neglected in previous clingfish descriptions. Briggs placed his new genus in the subfamily Gobiesocinae, an action of particular significance because Derilissus differs from all other genera included in this new world subfamily in having attached gill membranes. This, together with the discovery of another new genus from the western Atlantic, which clearly is unrelated to any genus currently included in the Gobiesocinae, has caused B6hlke and Robins (1970) to question the subfamilial classification within the family. A fourth new species of Derilissus, known from a single specimen, is described herein in order that its description may contribute toward a better understanding of the origin and affinities of this group of little known fishes. Terminology and methods follow those described by Briggs (1955), except for the caudal ray count. In many groups of fishes, including the closely related Callionymidae, the arrangement of the caudal rays may indicate generic relationships. In the following description the caudal rays are reported as a four-part formula, for example 2 + 76 + 1, indicates that there are 13 principal caudal rays (seven associated with the ventral hypural and six with the dorsal hypural) and three procurrent rays (two associated with the ventral hypural and one with the dorsal hypural). Principal caudal rays are defined as rays attached or articulating with the hypurals. Measurements are all straight-line measurements between points made with dial calipers. (Caudal-peduncle lengths used by Fraser apparently are projection measures rather than point to point measures.) All

Two New Species of the Clingfish Genus Derilissus (Gobiesocidae) from the Western Atlantic

Description.-The body shape is shown in Fig. 1. Body proportions are as follows, with the corresponding proportional measurements in parentheses: head length 33.3-36.6%9 (2.7-3.0), head width 28.6-31.8% (3.1-3.4), body depth 27.1-36.6% (3.3-3.6), and pelvic disk length 23.9-25.2% (3.9-4.3) of standard length; eye length 21.6-23.6,% (4.2-4.6) of head length and 59.2-80.9% (1.2-1.6) of interorbital width; snout length 28.2-36.4% (2.73.5) of head length; caudal peduncle length 28.9-50.0% (2.0-3.4) of caudal peduncle least depth. The fin ray counts are as follows, with the frequency of each count in parentheses: dorsal 7(1), 8(2) with the first dorsal ray unsegmented and fused; anal 7(1), 8(1), 9(1) with two specimens having counts of 7 and 9 not having the first anal ray unsegmented and fused; pectoral (both sides counted) 28(2), 29(3), 30(1); pelvic I, 4(3); principal caudal rays 7 + 7(3). All fin rays in all fins are unbranched. In Fig. 1 the anal fin is shown with seven fin rays, however there is another ray hidden within the skin at the anterior end.