Movable head armature in higher teleostean fishes

Synopsis A general pattern of movable head armature, composed of serrations on the borders of the lacrimal and preopercle and of a spine on the opercle, evolved among early acanthopterygians and is retained among many basal percoid families. In the more specialized higher teleostean groups this pattern is modified in various ways. Scorpaeniform fishes develop a suborbital stay with which the lacrimal is rigidly united. Elsewhere lacrimal serrations are generally absent, but in some bottom-resting forms preopercular or opercular armature becomes highly specialized. An association between head armature, fin spines, and changes in locomotion in the development of the acanthopterygian state of teleostean evolution is suggested.     

The functions and mechanisms of the protrusible upper jaws of some acanthopterygian fish

Photographs of Pterophyllum and Gasterosteus feeding indicate that they suck food into their mouths by expansion of the buccal and opercular cavities. The premaxillae are protruded as the mouth opens, and remain protruded as it closes. The mechanisms whereby these movements can be performed, by these and by more generalized acanthopterygians, are described. It is shown that the palatines of generalized acanthopterygians are so arranged as to prevent retraction of the premaxillae when the mouth is closed with the buccal cavity expanded.
It is estimated, from rough measurements on a few species, that a teleost cannot suck into its mouth food that is further from its mouth opening than about one-quarter of the length of its head. It is shown that protrusion of the premaxillae can be useful in getting the mouth opening close to food that is to be sucked in, expecially when it is to be taken from the bottom. The possible advantages of closing the mouth with the premaxillae protruded are discussed.
The origin of the acanthopterygian protrusile mechanism is discussed.     

The palatine bone and its associations in gadoid fishes

The articulation of the palatine bone in gadoid fishes has been thought of as a specialization of that group. It is shown that there are, in fact, three principal types of articulation, two of which are shared with other gadiform groups. The type of palatine articulation in other paracanthopterygians is briefly described and compared with that of various acanthopterygians. The supposed relationships of some gadoids are commented upon in the light of the specialized nature of some types of palatine articulation.     

Characterization of comparative genome‐derived simple sequence repeats for acanthopterygian fishes

Simple sequence repeats (SSRs) have become one of the most popular molecular markers for population genetic studies. The application of SSR markers has often been limited to source species because SSR loci are too labile to be maintained in even closely related species. However, a few extremely conserved SSR loci have been reported. Here, we tested for the presence of conserved SSR loci in acanthopterygian fishes, which include over 14 000 species, by comparing the genome sequences of four acanthopterygian fishes. We also examined the comparative genome‐derived SSRs (CG‐SSRs) for their transferability across acanthopterygian fishes and their applicability to population genetic analysis. Forty‐six SSR loci with conserved flanking regions were detected and examined for their transferability among seven nonacanthopterygian and 27 acanthopterygian fishes. The PCR amplification success rate in nonacanthopterygian fishes was low, ranging from 2.2% to 21.7%, except for Lophius litulon (Lophiiformes; 80.4%). Conversely, the rate in most acanthopterygian fishes exceeded 70.0%. Sequencing of these 46 loci revealed the presence of SSRs suitable for scoring while fragment analysis of 20 loci revealed polymorphisms in most of the acanthopterygian fishes. Population genetic analysis of Cottus pollux (Scorpaeniformes) and Sphaeramia orbicularis (Perciformes) using CG‐SSRs showed that these populations did not deviate from linkage equilibrium or Hardy–Weinberg equilibrium. Furthermore, almost no loci showed evidence of null alleles, suggesting that CG‐SSRs have strong resolving power for population genetic analysis. Our findings will facilitate the use of these markers in species in which markers remain to be identified.     

Homologies among different adductor mandibulae sections of teleostean fishes, with special regard to catfishes (Teleostei: siluriformes)

The adductor mandibulae complex has been a subject of discussion and uncertainties due to a wide range of differentiations and fusions that have occurred during teleost evolution. The adductor mandibulae of numerous catfishes was studied in detail and compared with that of several other teleosts described in the literature. Our observations and comparisons demonstrate that: 1) the adductors mandibulae Aomega, A2, and A3 of acanthopterygians correspond, respectively, to the Aomega, A2, and A3 of ostariophysines; 2) the antero-dorso-lateral (A1) and the antero-ventro-lateral (A1-OST) sections of the adductor mandibulae present, respectively, in acanthopterygians and in basal ostariophysines are the result of two different patterns of differentiation of this muscle; 3) some derived ostariophysines present a lateral section of the adductor mandibulae attached to the upper jaw (A0) that is not homologous with any other section of this muscle present in any other ostariophysine or acanthopterygian fish; 4) the configuration of the adductor mandibulae present in Diplomystes seems to be the plesiomorphic condition for catfishes; and 5) the muscle retractor tentaculi, present in a large number of catfishes, is derived from the inner section of the adductor mandibulae (A3) and, thus, is not homologous with the lateral bundle of this muscle (A0) that inserts on the upper jaw in some derived ostariophysine fishes.     

Evolutionary patterns in tropical marine reef fish feeding

The majority of tropical reef fishes are acanthopterygians. Most of them are percomorphs and thus are likely monophyletic. In accordance to modern systematics, the primitive types among the latter are large-mouthed suction feeders. Species from advanced families often have biting oral jaws with a reduced number and complexly shaped teeth. Mouth sizes decrease from the primitive towards the advanced reef fishes when ranked according to increasing family numbers (Nelson 1984). To create a functional resource axis, Randall's (1967) and Hobson's (1974) data on tropical reef fish feeding were re-interpreted by ranking food items from mobile to sessile prey. The primitive paracantho pterygian and acanthopterygian reef fishes are large-mouthed, suction-feeding predators on mobile prey. Most of the advanced, small-mouthed species are browsers and grazers, but often feed on mobile prey too. Obligatory specialists (monophagous and unable to switch) seem to be relatively rare among modern reef fishes. The trends stated above indicate a wealth of parallel developments in many advanced families of reef fishes towards small, often biting oral jaws. This parallelism may be the result of comparable regimes of selection pressures in reefs and of the need for newly evolved species to establish themselves within the already existing guilds.     

Unique occipital articulation with the first vertebra found in pristigasterids, chirocentrids, and clupeids (Teleostei: Clupeiformes: Clupeoidei)

This study recognized a W-shaped occipital articulation associated with the first vertebra in pristigasterids, chirocentrids, and clupeids as a unique character among teleosts, based on an evaluation of 43 species within 40 genera of these three families of the Clupeoidei. This occipital articulation is accompanied by an anterior extension of the neural arch bases, which are autogenous with the first vertebral centrum. In chirocentrids and many of the clupeid species examined, the anterior extension occurs on the second vertebra, and similar occipital articulation is found between the first and second vertebrae. The W-shaped occipital articulation is not found in any other teleosts, including Denticeps (suborder Denticipitoidei), which is thought to be a sister group to the suborder Clupeoidei. The W-shaped occipital articulation is absent in the other family of the Clupeoidei, Engraulidae, based on an evaluation of 11 species in 10 genera. Instead, the convex anterior surface of the first vertebral centrum forms a condyle that articulates with the basioccipital, and the neural arches fuse with the centrum behind this condyle. Therefore, it is unclear whether the anterior extension of the first vertebral neural arch bases, which causes the W-shaped occipital articulation, occurs in engraulids. Based on an evaluation of the osteological development of Konosirus punctatus and Engraulis japonicus, the cartilaginous neural arch bases of the first and second vertebrae extend anteriorly at an early developmental stage in the former, whereas no anterior extension of the first vertebral neural arch bases occurs at any developmental stage in the latter. Therefore, the anterior extension of the neural arch bases, which causes the W-shaped occipital articulation, seems to be a unique character of pristigasterids, chirocentrids, and clupeids among teleosts. Within the recent phylogenetic context, this character may be a synapomorphy of these three families.     

中国锯天牛族后翅翅脉研究(鞘翅目,天牛科,锯天牛亚科,锯天牛族)(英文)

对中国锯天牛族的后翅基部关节和后翅翅脉特征进行了研究,发现利用Kukalová-Peck和Lawrence (2004)的后翅命名系统能够很好地对中国锯天牛族后翅翅脉进行命名。但是在中国锯天牛族中,后中脉( MP)和前肘脉(CuA)在后缘并不合并;当前臀脉( AA3)和前肘脉(CuA3 +4)与后肘脉(CuP)相遇时,前臀脉(AA3)消失,前肘脉(CuA3 +4)和后肘脉(CuP)合并,因此楔室(W)仅由肘脉(Cu)的分支脉围成。尽管基部翅关节在研究的各属和各种之间没有表现出差异,但是后翅翅脉在土天牛属Dorysthenes和锯天牛属Prionus不同种类之间差异明显,这些特征包括径室的长宽比例和各边的长度关系、r3存在与否及其长度、后径脉的长度、楔室的长宽比例、以及后中脉(MP3 +4)和前肘脉(CuA3 +4)端部是否分叉等。因此,后翅翅脉特征在土天牛属Dorysthenes和锯天牛属Prionus分种时可能具有分类学意义。     

大熊猫腰带骨的特点

大熊猫Ailuropoda melanoleuca(David)是世界闻名的稀有珍贵兽类,仅产于我国的少数地区。由于材料的难得,对大熊猫形态学的研究还不多见。在骨学方面,张鹤宇等(1960)曾记述过颅骨及牙齿的比较解剖,朱靖(1974)曾涉及到幼体牙齿生长的序列。Davis(1964)曾进行过较系统的解剖工作,他的研究材料包括3例完整标本和一些零散骨骼,但缺少完整幼体标本(仅有1例幼体头骨)。     

Development of a model based method for investigating facet articulation

Reported investigations of facet articulation in the human spine have often been conducted through the insertion of pressure sensitive film into the joint space, which requires incision of the facet capsule and may alter the characteristics of interaction between the facet surfaces. Load transmission through the facet has also been measured using strain gauges bonded to the articular processes. While this method allows for preservation of the facet capsule, it requires extensive instrumentation of the spine, as well as strain-gauge calibration, and is highly sensitive to placement and location of the strain gauges. The inherently invasive nature of these techniques makes it difficult to translate them into medical practice. A method has been developed to investigate facet articulation through the application of test kinematics to a specimen-specific rigid-body model of each vertebra within a lumbar spine segment. Rigid-body models of each vertebral body were developed from CT scans of each specimen. The distances between nearest-neighboring points on each facet surface were calculated for specific time frames of each specimen's flexion/extension test. A metric describing the proportion of each facet surface within a distance (2 mm) from the neighboring surface, the contact area ratio (CAR), was calculated at each of these time frames. A statistically significant difference (p<0.037) was found in the CAR between the time frames corresponding to full flexion and full extension in every level of the lumbar spine (L1-L5) using the data obtained from the seven specimens evaluated in this study. The finding that the contact area of the facet is greater in extension than flexion corresponds to other findings in the literature, as well as the generally accepted role of the facets in extension. Thus, a biomechanical method with a sufficiently sensitive metric is presented as a means to evaluate differences in facet articulation between intact and treated or between healthy and pathologic spines.     

Fascia canals of the greater sciatic foramen and their practical importance

Fasciae and fat tissue spaces in the gluteal region, topography of the suprapiriform and infrapiriform foramina have been studied by means of a complex anatomical experimental technique. The suprapiriform foramen should be considered as a fascialosseous canal, as it is 4-4.5 cm long and 0.6-1.0 cm wide. It is formed by the upper margin of the greater sciatic notch covered with a thin fascia, fasciae of the gluteal and piriform muscles and the parietal layer of the pelvic fascia. The proper fascial vaginae of the upper gluteal vessels and nerves are adhered to fascial walls of the canal. This peculiarity is used for the method of ligation of the superior gluteal artery within the limits of the suprapiriform canal. The infrapiriform foramen is either narrow or wide enough (up to 2.0 cm in diameter). Inferior gluteal vessels at the level of the sacrospinous ligament go from the parietal layer of the pelvic fascia into the duplicature of the deeper layer of musculus gluteus maximus. The inferior gluteal nerve, above the lower margin of the piriform muscle, ajoining the vessels gets into the fissure of the parietal layer of the pelvic fascia, under the lower margin neurovascular fasciculus also goes through the fissure of the pelvic fascial parietal layer, downward and parallel to the inferior gluteal vessels. The knowledge of possible ways of connections through the canals of the greater sciatic foramen, fat tissue spaces at the subperitoneal level of the small pelvis and the gluteal region is of great practical value.     

Blood flow to long bones indicates activity metabolism in mammals, reptiles and dinosaurs

The cross-sectional area of a nutrient foramen of a long bone is related to blood flow requirements of the internal bone cells that are essential for dynamic bone remodelling. Foramen area increases with body size in parallel among living mammals and non-varanid reptiles, but is significantly larger in mammals. An index of blood flow rate through the foramina is about 10 times higher in mammals than in reptiles, and even higher if differences in blood pressure are considered. The scaling of foramen size correlates well with maximum whole-body metabolic rate during exercise in mammals and reptiles, but less well with resting metabolic rate. This relates to the role of blood flow associated with bone remodelling during and following activity. Mammals and varanid lizards have much higher aerobic metabolic rates and exercise-induced bone remodelling than non-varanid reptiles. Foramen areas of 10 species of dinosaur from five taxonomic groups are generally larger than from mammals, indicating a routinely highly active and aerobic lifestyle. The simple measurement holds possibilities offers the possibility of assessing other groups of extinct and living vertebrates in relation to body size, behaviour and habitat.     

The skull of Morganucodon

Morganucodon is a triconodont (atherian) mammal from the Lower Jurassic. Two species are described: M. oehleri from China and M. watsoni from Wales. The skull in M. walsoni is 26 mm long; M. oehleri is slightly larger. The dentition is differentiated functionally into incisors, canines, premolars and molars. The pineal foramen is closed. The prefrontals, postfrontals and postorbitals are lost. Septomaxilla, quadratojugal, tabular and pterygoid flanges are retained. The bony external nares are unpaired. The nasal cavity had the mammalian complement of turbinals. The posterior palate has ridges and troughs similar to those in tritylodonts, triconodonts and multituberculates. The alisphenoid ascending process is narrow and is not in contact with the anterior lamina of the petrosal, lying lateral to it. There is a cavum epiptericum, as in late therapsids. The anterior lamina forms the lateral braincase wall, perforated by the foramina pseudovale and pseudorotundum. There is a squamosal-dentary articulation, but the reptilian jaw joint is retained. The ear resembles that in later therapsids, with the tympanum in the lower jaw. The small quadrate was moveable, buttressed medially be a large stapes. Sound conduction from the tympanum was via articular, quadrate and stapes. The systematic position of Morganucodon is discussed.     

A Tachyglossid-Like Humerus from the Early Cretaceous of South-Eastern Australia

A partial right humerus has been recovered from the Early Cretaceous (Albian) Eumeralla Formation at Dinosaur Cove in south-eastern Australia. General morphology, size and the presence of a single epicondylar foramen (the entepicondylar) suggest that the bone is from a mammal or an advanced therapsid reptile. The humerus is similar in size, shape and torsion to the equivalent bone of extant and late Neogene echidnas (Tachyglossidae) but, contrary to the situation in extant monotremes, in which the ulna and radius articulate with a single, largely bulbous condyle, it bears a shallow, pulley-shaped (i.e. trochlear-form) ulnar articulation that is confluent ventro-laterally with the bulbous radial condyle. This form of ulnar articulation distinguishes this bone from the humeri of most advanced therapsids and members of several major groups of Mesozoic mammals, which have a condylar ulnar articulation, but parallels the situation found in therian mammals and in some other lineages of Mesozoic mammals. As in extant monotremes the distal humerus is greatly expanded transversely and humeral torsion is strong. Transverse expansion of the distal humerus is evident in the humeri of the fossorial docodont Haldanodon, highly-fossorial talpids and some clearly fossorial dicynodont therapsids, but the fossil shows greatest overall similarity to extant monotremes and it is possible that the peculiar elbow joint of extant monotremes evolved from a condition approximating that of the fossil. On the basis of comparisons with Mesozoic and Cainozoic mammalian taxa in which humeral morphology is known, the Dinosaur Cove humerus is tentatively attributed to a monotreme. However, several apparently primitive features of the bone exclude the animal concerned from the extant families Tachyglossidae and Ornithorhynchidae and suggest that, if it is a monotreme, it is a stem-group monotreme. Whatever, the animal's true affinity, the gross morphology of its humerus indicates considerable capacity for rotation-thrust digging.     

Description of two new genera, Santelmoa and Bentartia and two new species of Zoarcidae (Teleostei, Perciformes) from the Southern Ocean

Two new genera of lycodine zoarcid fish, Santelmoa and Bentartia, and two new species, Santelmoa carmenae and Bentartia cinerea, are described from 13 specimens collected from the Gerlache Strait, Southern Ocean, at 1,056-m depth. Santelmoa can be distinguished from all other lycodine genera by the combination of the following characters: anterior portion of frontals fused; scapular foramen open; ceratohyal–epihyal articulation interdigitating; cranium narrowed; supratemporal commissure and occipital pores absent; intercalar reaching the prootic; parasphenoid wing well developed; palatal arch well developed; posterior hyomandibular ramus short; post-temporal ventral ramus well developed; six branchiostegal rays; vertebrae asymmetrical; pelvic fin rays ensheathed; scales, lateral line, pyloric caeca, palatine and vomerine teeth present. Bentartia differs from the remaining lycodine genera by the following combination of characters: basioccipital and exoccipitals fused; supraoccipital–exoccipital articulation broadly contacting; ceratohyal–epihyal articulation interdigitating; post-temporal ventral ramus weak; two posterior nasal pores; cranium narrowed; supratemporal commissure and occipital pores absent; intercalar set posteriorly; palatal arch well developed; posterior hyomandibular ramus not elongate; parasphenoid wing high; six branchiostegal rays; vertebrae asymmetrical; pelvic fin rays ensheathed; scales, lateral line, pyloric caeca, palatine and vomerine teeth present. The relationships of the two new genera are discussed.     

软刺裸裂尻鱼的年龄鉴定

检测并比较了软刺裸裂尻鱼（Schizopygopsis malacanthus）鳞片、耳石、脊椎骨和背鳍条的年轮特征。结果表明,这4种材料上均具有年轮特征,以耳石最明显,且易于识别,为最好的年龄鉴定材料;鳞片上的年轮也较明显,但高龄鱼外围的年轮常挤在一起,使鉴定结果偏低;背鳍条上的环纹清晰,但边缘出现轮纹的重叠,影响年龄准确判读;脊椎骨上通常只能观察到比较有限的环纹,不适合用作年龄鉴定。     

Secondary chondrocyte-derived Ihh stimulates proliferation of periosteal cells during chick development

The development of the skull is characterised by its dependence upon epigenetic influences. One of the most important of these is secondary chondrogenesis, which occurs following ossification within certain membrane bone periostea, as a result of biomechanical articulation. We have studied the genesis, character and function of the secondary chondrocytes of the quadratojugal of the chick between embryonic days 11 and 14. Analysis of gene expression revealed that secondary chondrocytes formed coincident with Sox9 upregulation from a precursor population expressing Cbfa1/Runx2: a reversal of the normal sequence. Such secondary chondrocytes rapidly acquired a phenotype that is a compound of prehypertrophic and hypertrophic chondrocytes, exited from the cell cycle and upregulated Ihh. Pulse and pulse/chase experiments with BrdU confirmed the germinal region as the highly proliferative source of the secondary chondrocytes, which formed by division of chondrocyte-committed precursors. By blocking Hh signalling in explant cultures we show that the enhanced proliferation of the germinal region surrounding the secondary chondrocytes derives from this Ihh source. Additionally, in vitro studies on membrane bone periosteal cells (non-germinal region) demonstrated that these cells can also respond to Ihh, and do so both by enhanced proliferation and precocious osteogenesis. Despite the pro-osteogenic effects of Ihh on periosteal cell differentiation, mechanical articulation of the quadratojugal/quadrate joint in explant culture revealed a negative role for articulation in the regulation of osteocalcin by germinal region descendants. Thus, the mechanical stimulus that is the spur to secondary chondrocyte formation appears able to override the osteogenic influence of Ihh on the periosteum, but does not interfere with the cell cycle-promoting component of Hh signalling.     

Mechanical regulation of secondary chondrogenesis

The development of the skull is characterised by its dependence upon epigenetic influences. One of the most important of these is secondary chondrogenesis, which occurs following ossification within certain membrane bone periostea, as a result of biomechanical articulation. We have studied the genesis, character and function of the secondary chondrocytes of the quadratojugal of the chick between embryonic days 11 and 14. Analysis of gene expression revealed that secondary chondrocytes formed coincident with Sox9 upregulation from a precursor population expressing Cbfa1/Runx2: a reversal of the normal sequence. Such secondary chondrocytes rapidly acquired a phenotype that is a compound of prehypertrophic and hypertrophic chondrocytes, exited from the cell cycle and upregulated Ihh. Pulse and pulse/chase experiments with BrdU confirmed the germinal region as the highly proliferative source of the secondary chondrocytes, which formed by division of chondrocyte-committed precursors. By blocking Hh signalling in explant cultures we show that the enhanced proliferation of the germinal region surrounding the secondary chondrocytes derives from this Ihh source. Additionally, in vitro studies on membrane bone periosteal cells (nongerminal region) demonstrated that these cells can also respond to Ihh, and do so both by enhanced proliferation and precocious osteogenesis. Despite the pro-osteogenic effects of Ihh on periosteal cell differentiation, mechanical articulation of the quadratojugal/quadrate joint in explant culture revealed a negative role for articulation in the regulation of osteocalcin by germinal region descendants. Thus, the mechanical stimulus that is the spur to secondary chondrocyte formation appears able to override the osteogenic influence of Ihh on the periosteum, but does not interfere with the cell cycle-promoting component of Hh signalling.     

Brood chambers constructed from spines in fossil and Recent cheilostome bryozoans

Most cheilostome bryozoans brood their larvae in skeletal structures called ovicells which, in evolutionary terms, were derived from spines. Ovicells in the great majority of fossil and Recent cheilostomes, however, have lost all or most traces of their spinose origin. Here we review the occurrence of spinose (including costate) brood chambers in cheilostomes, investigating in detail 32 species belonging to ten genera among five families (Calloporidae, Monoporellidae, Macroporidae, Cribrilinidae and Tendridae). Spinose ovicells are moderately common in the Upper Cretaceous, where they are recorded in 28 species, and also occur in one Palaeocene, seven Eocene‐Miocene and 11 Recent species. The most primitive cheilostome ovicells occur in mid‐Cretaceous calloporids in which a group of mural spines belonging to the distal zooid were apparently bent towards the maternal zooid to form a cage‐like structure for reception of the embryo. The bases of these spines were initially aligned in a distally concave row that later became straight, distally convex and finally horseshoe‐shaped, affording progressively better protection for the developing embryo. We suggest that primitive monoporellids inherited from calloporid ancestors a distally concave arrangement of ovicell spine bases, while cribrilinids inherited a horseshoe‐shaped arrangement. Important trends that can be recognized in early ovicell evolution include: (1) loss of basal spine articulation; (2) spine flattening; (3) closure of the gaps between spines; (4) reduction in spine number (through loss or fusion), and (5) development of a concave ovicell floor. The conventional ‘unipartite’ ovicells found in the majority of cheilostomes may have originated either by spine fusion, as seems likely in some cribrilinids, or through a progressive loss of spines via an intermediate stage, seen in some calloporids and in two monoporellids, where the ovicell comprises a large pair of flattened spines. The spinose ovicells of some monoporellids and macroporids subsequently evolved investments of hypostegal coelom that allowed secretion of a surface layer of cryptocystal calcification. Acanthostegous brood chambers characteristic of Tendridae apparently provide an example of independent evolution of spinose brooding structures. © 2005 The Natural History Museum, London, Zoological Journal of the Linnean Society, 2005, 144 , 317?361.