Anteromedial Process Research Articles

The osteology of the lacertid genus Darevskia Arribas, 1999 (Squamata, Lacertidae)

A total of 230 cleared and alizarin stained and 136 radiographed specimens of Darevskia belonging to 47 nominal taxa (species, subspecies or singular clades) including the seven parthenogenetic ones and a triploid hybrid were studied. Sixteen osteological characters in all the tried species were analyzed. These characters by corporal regions were: skull characters: 1.—number of premaxillary teeth; 2.—number of maxillary teeth; 3.—number of dentary teeth; 4.—teeth morphology; 5.—presence of anterolateral process in the postfrontal bone; 6.—presence of anteromedial process in the postorbital bone; 7.—comparative lengths of the postorbital and postfrontal bones; 8.—overlap degree between the postorbital and the squamosal bones. Postcranial characters: 9.—existence of visible (ossified) ribs associated with the third presacral vertebrae; 10.—sternal/xiphisternal costal formula and presence of inscriptional ribs; 11.—number of presacral vertebrae; 12.—number of posterior dorsal vertebrae (short presacral ribs); 13.—presence and form of the sternal fontanelle; 14.—form of the clavicles (emarginated or marginated); 15.—interclavicle form; 16.—morphology of first autotomic vertebrae of the tail. Our goals were to characterize osteologically the different species of Darevskia, to contrast their relationships traced from osteological traits with the available genetic-derived phylogenies of the group, to compare the osteological characteristics of the parthenogenetic species with their bisexual parental species, and to comment on their parentage and character polarity. Finally, we aimed to search for osteological characteristics of the different groups within Darevskia, diagnosing them for the first time. The results, commented on by characters, are available in the main text, and taxa characteristics are easily consultable and condensed in Table 1. Osteological characteristics of Darevskia, together with available phylogenetic trees, have permitted us to define some new groups within Darevskia (raddei, chlorogaster, defilippi, and parvula new groups) (Appendix 3), which are reciprocally monophyletic and have diagnostic characteristics. All of them are diagnosed and named as subgenera to be used if necessary, instead of the partial, old and not always comprehensive groups.

The first mamenchisaurid from the Upper Jurassic Dongxing Formation of Guangxi, southernmost China

ABSTRACT A new mamenchisaurid sauropod dinosaur, Jingia dongxingensis gen. et sp. nov. from the Upper Jurassic of Southernmost China is reported here. The holotype consists of partly preserved dorsal, sacral, and caudal vertebrae, left and right ulna, and right femur. Anatomical comparison and phylogenetic analysis indicate that the new taxon belongs to Mamenchisauridae and bears a unique combination of characteristics, such as the ratio of the length of the neural spine to the narrowest width of the neural arch of the dorsal vertebra is about 4.4; sacral centrum is opisthocoelous with shallow depression exists on the lateral surface; centrum of anterior caudal vertebrae are amphicoelous, and the articular surfaces are transversely compressed; the anterolateral and anteromedial processes of the ulna are generally perpendicular in proximal view. Phylogenetically, Jingia dongxingensis gen. et sp. nov. is located at the later diverged position in Mamenchisauridae. This discovery increases the diversity of Mamenchisauridae and provides additional information to help understand the evolutionary radiation of eusauropods in China. It also indicates that this lineage is more competitive than penecontemporaneous neosauropods to dominate the Late Jurassic of East Asia.

Systematic Review and Cranial Osteology of Petersius with Redescription of P. conserialis (Teleostei: Alestidae) from the Rufiji and Ruvu Rivers of Tanzania

We review the systematics of the monotypic alestid genus Petersius and provide a taxonomic redescription of P. conserialis from eastern Tanzania. Morphological investigation includes direct observation and examination of radiographed and µCT-scanned data from type and non-type specimens. We delimit the taxon's geographic distribution along the lowland regions of the Rufiji and Ruvu river basins in Tanzania and provide information on ecology, sexual dimorphism, and ontogenetic variation. Petersius is herein diagnosed by the possession of a unique cuspidation patterning of the inner-row premaxillary dentition and a distinctively shaped anterodorsal margin of the supraoccipital crest. It shares with some species of Phenacogrammus a sigmoid-shaped process on the dorsal margin of the second infraorbital, a feature lacking in other alestid taxa. Additional features of potential utility for ongoing investigation of relationships among alestid genera include the possession of contralateral premaxillae separated by the anteromedial process of the mesethmoid and without interdigitations connecting the medial surfaces of the premaxillae; four, occasionally five or six, small outer-row premaxillary teeth implanted alternately with those of the inner row; a dentary lacking a pair of conical inner-row teeth proximal to the symphysis; a dorsal posttemporal fossa that is smaller than the ventral fossa; a median third posttemporal fossa located entirely within the epioccipital; a truncate dorsomedial cranial fontanel; and a complete circumorbital series forming an uninterrupted ring around the orbit in adult specimens.

The too-long anterior process and osteochondral lesion of the talus: Is there an anatomical predisposition? A case-control study on 135 feet

IntroductionThe too-long anterior process (TLAP) increases mechanical stress on the hindfoot and could lead to osteochondral lesions of the talus (OLT) by localized hyper-pressure. The purpose of this study is to investigate an association between TLAP and OLT in children. MethodsThis is a retrospective, multicenter, case-control study conducted between 2010 and 2020. The OLT group was compared to a control group (CoG). TLAP is characterized by a distance between the anteromedial process of the calcaneus and the navicular bone (CN) of< 5 mm. ResultsForty-three feets were included in the OLT group and 92 in the CoG. The OLT group had a lower CN distance on CT than the CoG, a median of 2.8 mm versus 3.75 mm (p = 0.002); 86% of patients (37 feet/43) in the OLT group had a CN distance of< 5 mm (OR=3.0 [1.1; 9.5], p = 0.023) compared to 67% in the CoG. DiscussionThe OLT group had an increased risk of developing TLAP compared to the CoG. Level of evidenceIII.

&lt;p class="Body"&gt;&lt;strong&gt;New taxonomic and ontogenetic data on oribatid mites of the genus &lt;em&gt;Eutegaeus &lt;/em&gt;(Acari, Oribatida, Eutegaeidae)&lt;/strong&gt;&lt;/p&gt;

Two new species of the genus Eutegaeus (Oribatida, Eutegaeidae) are described based on specimens from moss in the Queulat National Park of Chile. Eutegaeus aysenensis sp. nov. (description based on the adult, larva, deuto- and tritonymph) is morphologically similar to that of Eutegaeus lagrecai in having long, flagellate interlamellar and notogastral setae and rod-like bothridial seta; it differs from the latter by having smaller body size and comparatively long bothridial seta, the lamella having anteromedial process, and by the absence of striate ornamentation on notogaster. Eutegaeus queulatensis sp. nov. (description based on the adult, proto- and tritonymph) is morphologically similar to that of Eutegaeus membraniger in having a triangular anteromedial lamellar process, long, rod-like bothridial seta, foveate lamella, and dorsal notogastral setae of medium length; it differs from the latter by having smaller body length, thickened notogastral setae, flagellate interlamellar setae, setiform lamellar setae, a tubercle on epimere III, and absence of an anterolateral tooth on the lamella. Based on new information, several characters in the generic diagnosis of Eutegaeus adults are modified or expanded, and a preliminary diagnosis for juveniles is presented. The larva of E. aysenensis sp. nov. is the first to be described for the genus. Nymphs of four species of Eutegaeus are compared.

First discovery of Megantereon skull from southern China

ABSTRACT The sabertoothed cat Megantereon is an iconic carnivore in the Pleistocene of Eurasia, yet its fossil record is extremely rare and highly fragmentary in southern China (and the whole Oriental Realm). Here we report a nearly complete and undeformed skull of Megantereon from Sabretooth Cave, Chongzuo, southernmost China, middle Early Pleistocene. The general morphology allows us to assign it to Megantereon nihowanensis, differing from the northern China population of M. nihowanensis by better developed P4 parastyle and longer c-p3 diastema. The excellent preservation allows us to exam the previous unrecognised cranial characters. Megantereon shows a clear affinity to Smilodon in many aspects, e.g. wide nasal with parallel lateral border and smoothly curved posterior border, presence of moderately developed antero-medial process of the nasal, presence of anterior accessory process of the frontal, and a distinct frontal depression behind the posterior border of the nasal. These characters are markedly different from those of Homotherium, suggesting a deep divergence of the two lineages of sabertoothed cats. The rarity of Megantereon in southern China and southeastern Asia probably suggests this genus is not well adaptive to the closed forest environment.

A revision of the referred specimen of Chuanjiesaurus anaensis Fang et al., 2000: a new early branching mamenchisaurid sauropod from the Middle Jurassic of China

ABSTRACT We present a revision of the referred specimen (LFGT LCD 9701–1) of Chuanjiesaurus anaensis from the Middle Jurassic Chuanjie Formation of Yunnan Province, southwest China, and demonstrate that LCD 9701-1 is differentiated from the holotype by numerous features. Therefore, it can be referred to a new taxon (Analong chuanjieensis gen. et sp. nov.). Analong bears a unique combination of characters, such as caudal transverse processes persisting until the 10th caudal (15th in Chuanjiesaurus); weakly developed posterior condylar ball in anterior caudal vertebrae (well developed in Chuanjiesaurus); ulnar anterolateral and anteromedial processes sub-equal in length and forming an angle of about 45 degrees (unequal in length and 60 degrees in Chuanjiesaurus anaensis); proximal width of metacarpal II 7% the length of radius (lowest value among mamenchisaurids); pubic distal width approximately 40% of its total length (greatest value among mamenchisaurids). Comparative study and cladistic analysis show Analong chuanjieensis is the earliest branching of Mamenchisauridae, while the (Mamenchisaurus + Chuanjiesaurus anaensis) branching is the latest branching of this clade. Our revision of Analong chuanjieensis increases the diversity of Mamenchisauridae and indicates the evolution of Mamenchisauridae is a complex than previously realised.

A new genus and three new species of dactylogyrids (Monogenea), gill parasites of the threadfin bass, Pronotogrammus multifasciatus Gill (Perciformes: Serranidae) in the Southeastern Pacific Ocean off Peru.

Pronotogrammella n. g. is erected to accommodate Pronotogrammella boegeri n. sp. (type-species), Pr. scholzi n. sp. and Pr. multifasciatus n. sp. (Monogenea: Dactylogyridae). The new species are gill parasites of the threadfin bass Pronotogrammus multifasciatus Gill (Perciformes: Serranidae), a demersal teleost collected from off the coastal zone of Puerto Pizarro, Tumbes, Peru. Pronotogrammella n. g. is mainly characterised by having broadly fork-shaped dorsal anchors, which have an accessory anchor sclerite articulated to the tip of the superficial roots. Pronotogrammella n. g. is also characterised by having: (i) a tubular tapered-shaped male copulatory organ (MCO), filamentous distally, with a clockwise coil at distal end or not, lacking accessory piece; (ii) a dorsal bar with an anteromedial delicate umbelliform membrane supported by two processes; (iii) hooks with upright blunt thumb and uniform shank; (iv) a vaginal aperture dextrolateral; (v) a subquadrangular haptor, with inconspicuous lateral flaps and lacking haptoral reservoirs; and (vi) eye-spot or chromatic granules absent. Pronotogrammella boegeri n. sp. is characterised by its crosier-shaped MCO having a clockwise coil at distal end and by its dorsal bar with a straight anteromedial processes. Pronotogrammella scholzi n. sp. is typified by possessing of a dorsal bar with the anteromedial processes like cow horns, hoof-shaped deep roots of the dorsal anchors and a broader shaft of the MCO. Pronotogrammella multifasciatus n. sp. differs from all congeners by having a tubular MCO with twisted shaft and a base with a short and broad arm and by having an almost dumbbell-shaped ventral bar.

A new species of parasitic copepod (Siphonostomatoida: Lernaeopodidae: Neoalbionella Özdikmen, 2008) infecting the skin of a gulper shark, Centrophorus sp. (Squaliformes: Centrophoridae), in the Gulf of Mexico, with a key to species of Neoalbionella

AbstractWe describe male and female specimens of a species of NeoalbionellaÖzdikmen, 2008 (Siphonostomatoida, Lernaeopodidae), Neoalbionella dannytangisp. nov., infecting the skin of a gulper shark Centrophorus sp. (Centrophoridae) in the northern Gulf of Mexico. Females of the new species most closely resemble those of Neoalbionella globosa (Leigh-Sharpe, 1918) but are unique among congeners by having the combination of 1) terminal endopodal segment of antenna with a reduced distal tubercle having a minute protuberance, 2) maxillule with a spinulose lateral palp and praecoxal endite, 3) maxilla with a swollen tip nearly parallel with the distal surface of the bulla, and 4) maxilliped with a sub-circular spinulose pad along the proximal myxal margin of the corpus maxillipedis. The male copepod was attached to the tip of a female’s posterior process and was assigned to Neoalbionella by having a cephalosome nearly equal in length to the trunk and tapered caudal rami directed posteroventrally (swollen and directed anterodorsally in males of Lernaeopoda von Nordmann, 1832). It was distinct from those of all other congeners by having 1) an antenna terminal endopodal segment and maxillule similar to that of the female, 2) a maxilla syncoxa with an anteromedial process having seven large, conical denticles, 4) a bifid mediative process approximately as wide as the length of the shortest lobe, and 5) a caudal ramus with a unique configuration and number of setae. This is the second report of a species of Neoalbionella from the Gulf of Mexico and the third nominal species of Neoalbionella reported from gulper sharks (Centrophorus spp.). We also provide keys to females and males of Neoalbionella.

Contribution to the knowledge of the oribatid mite genus Lamellarea (Acari, Oribatida, Lamellareidae)

A new species of the genus Lamellarea (Oribatida, Lamellareidae) is described from nests of the termite Trinervitermes trinervoides (Sjöstedt) in the Franklin Game Reserve (Bloemfontein, South Africa). Lamellarea koki sp. nov. differs from all species of the genus by the following main morphological traits: lamellar cusps triangular, without anteromedial processes, separated; translamella long; rostrum with median indentation; several ridges located near tutoria. A revised generic diagnosis, an identification key to known species, and data on the distribution and ecology of Lamellarea are presented.

A new species of troodontid theropod (Dinosauria: Maniraptora) from the Horseshoe Canyon Formation (Maastrichtian) of Alberta, Canada

Troodontid material from the Maastrichtian of North America is extremely rare, beyond isolated teeth from microvertebrate sites. Here we describe troodontid frontals from the early Maastrichtian Horseshoe Canyon Formation (Horsethief Member). The most complete specimen, TMP 1993.105.0001, is notably foreshortened and robust when compared with numerous specimens referred to Troodon from the Dinosaur Park Formation, and exhibits several characteristics that distinguish it from other Late Cretaceous troodontids. Morphometric analyses reinforce shape differences between TMP 1993.105.0001 and other North American troodontids, and show that proportional differences are independent of size. We therefore erect a new taxon, Albertavenator curriei gen. et sp. nov., which is diagnosed by the following autapomorphies: (1) primary supraciliary foramen is truncated anteriorly by the lacrimal contact; (2) superficial (ectocranial) surface of the frontal proportionally shorter than all known troodontids, with a length to width ratio under 1.3; and (3) frontoparietal contact in which an enlarged lappet of the frontal extends medially to extensively overlap the lateral region of the anteromedial process of the parietal. Interestingly, tooth and jaw morphology from the single relatively complete dentary recovered from the Horseshoe Canyon cannot be distinguished from dentaries and teeth from the Dinosaur Park Formation. If the dentary and teeth from the Horsethief Member of the Horseshoe Canyon Formation prove to belong to A. curriei, extensive overlap in tooth morphology between the Dinosaur Park and Horseshoe Canyon formations reinforces the notion that tooth morphotypes do not exhibit strong correspondence to species alpha diversity, and may encompass multiple closely related taxa.

Arthroscopic Resection of Too-Long Anterior Process of the Calcaneus

A too-long anterior process (TLAP) of the calcaneus is an elongated anteromedial process of the calcaneus impinging the navicular or the talar head. TLAP can cause recurrent ankle sprain, peroneal muscle spasm, or persistent tarsal pain in adolescents. Arthroscopic resection is indicated if the symptoms do not respond to conservative treatment. It has the advantage of assessment of completeness of bone resection and treatment of associated lesions of the adjacent joints. The purpose of this technical note is to report an arthroscopic approach of the resection of the TLAP with the lateral midtarsal portal as the viewing portal.

Proposal of Whittingtonocotyle n. gen. (Dactylogyroidea: Dactylogyridae), with the description of two new species from the gills of Hoplerythrinus unitaeniatus (Characiformes: Erythrinidae) in Brazil.

Whittingtonocotyle n. gen. is proposed for species with a male copulatory organ sclerotized, spiral, clockwise, non-articulated to the accessory piece; prostatic reservoir separated into two/three zones with one or two terminal areas densely stained; vaginal opening dextrodorsal; anchors without well-defined roots; and dorsal bar with anteromedial protuberance. Two new species of Whittingtonocotyle n. gen. are described from the gills of Hoplerythrinus unitaeniatus (Agassiz), from two rivers of the State of Pará, Brazil. Whittingtonocotyle caetei n. sp. (type species) is characterized by possessing ventral anchor with deep root truncate; prostatic reservoir separated into two zones with one terminal area densely stained; and vaginal canal heavily sclerotized, coiled and dilate distally. Whittingtonocotyle jeju n. sp. is distinguished from the previously species mainly by having a male copulatory organ comprising a coil of about 19 rings (29 rings in Whittingtonocotyle caetei n. sp.); a prostatic reservoir separated into three zones with two terminal areas densely stained; vaginal canal sclerotized, sigmoid; and dorsal bar with short anteromedial process (elongate in Whittingtonocotyle caetei n. sp.).

Torvosaurus gurneyi n. sp., the Largest Terrestrial Predator from Europe, and a Proposed Terminology of the Maxilla Anatomy in Nonavian Theropods

The Lourinhã Formation (Kimmeridgian-Tithonian) of Central West Portugal is well known for its diversified dinosaur fauna similar to that of the Morrison Formation of North America; both areas share dinosaur taxa including the top predator Torvosaurus, reported in Portugal. The material assigned to the Portuguese T. tanneri, consisting of a right maxilla and an incomplete caudal centrum, was briefly described in the literature and a thorough description of these bones is here given for the first time. A comparison with material referred to Torvosaurus tanneri allows us to highlight some important differences justifying the creation of a distinct Eastern species. Torvosaurus gurneyi n. sp. displays two autapomorphies among Megalosauroidea, a maxilla possessing fewer than eleven teeth and an interdental wall nearly coincidental with the lateral wall of the maxillary body. In addition, it differs from T. tanneri by a reduced number of maxillary teeth, the absence of interdental plates terminating ventrally by broad V-shaped points and falling short relative to the lateral maxillary wall, and the absence of a protuberant ridge on the anterior part of the medial shelf, posterior to the anteromedial process. T. gurneyi is the largest theropod from the Lourinhã Formation of Portugal and the largest land predator discovered in Europe hitherto. This taxon supports the mechanism of vicariance that occurred in the Iberian Meseta during the Late Jurassic when the proto-Atlantic was already well formed. A fragment of maxilla from the Lourinhã Formation referred to Torvosaurus sp. is ascribed to this new species, and several other bones, including a femur, a tibia and embryonic material all from the Kimmeridgian-Tithonian of Portugal, are tentatively assigned to T. gurneyi. A standard terminology and notation of the theropod maxilla is also proposed and a record of the Torvosaurus material from Portugal is given.

A new metriorhynchid crocodylomorph from the Lower Kimmeridge Clay Formation (Late Jurassic) of England, with implications for the evolution of dermatocranium ornamentation in Geosaurini

A new metriorhynchid crocodylomorph from the Lower Kimmeridge Clay Formation (Kimmeridgian, Upper Jurassic) of England is described. This specimen, a three-dimensionally preserved skull and left mandibular ramus, is referred to a new species: Torvoneustes coryphaeus sp. nov. Within the genus Torvoneustes, T. coryphaeus sp. nov. is unique as it has a long anteromedial process of the frontal, ornamented dermatocranium, and the supraorbital notch forms a strongly acute angle. Our phylogenetic analysis confirms the placement of this specimen in Torvoneustes. The dentition of T. coryphaeus sp. nov., like that of the type species, has a blunt apex, crown basal–mid regions with numerous tightly packed apicobasally aligned ridges, and apical region with an anastomosed pattern of ridges that interact with the carinae. Within Thalattosuchia these dental characteristics are only found in Torvoneustes and the teleosaurid Machimosaurus. The heavily ornamented dermatocranium of T. coryphaeus sp. nov. is in contrast to the unornamented (nasals and frontal)–lightly ornamented (maxillae and premaxillae) pattern seen in Torvoneustes carpenteri. Curiously, this pattern of reduction and loss of dermatocranium ornamentation is also observed in Metriorhynchus, Dakosaurus, and the subclade Rhacheosaurini. We hypothesize that the ‘smooth’ dermatocranium of Late Jurassic metriorhynchids evolved independently in each subclade (parallel evolution), and would have reduced drag, thereby making locomotion through water more energy efficient. © 2013 The Linnean Society of London

Osteology, ontogeny, and phylogenetic position of Sinophoneus yumenensis (Therapsida, Dinocephalia) from the Middle Permian Dashankou Fauna of China

ABSTRACT Sinophoneus yumenensis and Stenocybus acidentatus are the only dinocephalians from China, and the latter taxon has been proposed to be a junior synonym of the former. Here I confirm this synonymy on the grounds that the differences between the two putative taxa are due to ontogenetic variation. The osteology of Sinophoneus yumenensis is described in detail based on both previously described specimens and several new ones from the same locality. Sinophoneus yumenensis differs from all other anteosaurs in having premaxillary dorsal processes that are separated by relatively long nasal anteromedial processes, and vomers without raised, elongated edges; from all other anteosaurs except Archaeosyodon praeventor in having distinct frontal posterolateral processes, and a wide intertemporal region formed partly by long posterior processes of the postfrontals that approach the posterior edge of the skull roof; and from Archaeosyodon praeventor in having a well-developed midline ridge on skull roof. A revised phylogenetic analysis including the new material recovers Sinophoneus as the most basal known anteosaurid. SUPPLEMENTAL DATA—Supplemental materials are available for this article for free at www.tandfonline.com/UJVP

Three new species of Protogyrodactylus Johnston &amp; Tiegs, 1922 (Monogenoidea: Dactylogyridae) from the gills of the longtail silverbiddy Gerres longirostris (Teleostei: Gerreidae) in the Red Sea

Twenty-one specimens of the longtailed silverbiddy Gerres longirostris (Gerreidae) were examined for dactylogyrid parasites from the Nabq Managed Resource Protected Area, Ras Mohammed National Park (Red Sea) near Sharm El-Sheikh, South Sinai, Egypt. The diagnosis of Protogyrodactylus Johnston & Tiegs, 1922 was amended, and three new species, P. federicae n. sp., P. zullinii n. sp. and P. alatus n. sp., were recovered and described; the prevalence of each species was 100%. P. federicae most closely resembled P. alienus Bychowsky & Nagibina, 1974, but differed from it by possessing two anteromedial projections on the ventral bar, a claw-like ventral anchor sclerite and spatulate dorsal bars. P. zullini was most similar to P. quadratus Johnston & Tiegs, 1922, from which it differed by having a distal hook on the superficial root of the dorsal anchor, an evenly curved ventral anchor shaft and point, and a flange on the bulbous base of the male copulatory organ. P. alatus was closest to P. youngi Bychowsky & Nagibina, 1974, from which it differed by having delicate anchors and two prominent anteromedial processes on the ventral bar.

A new species of Carcharodontosaurus (Dinosauria: Theropoda) from the Cenomanian of Niger and a revision of the genus

ABSTRACT The systematics and taxonomy of the large allosauroid Carcharodontosaurus are reviewed and a new species of this theropod is described from the Late Cretaceous (Cenomanian) Echkar Formation of Niger, which is roughly coeval with Cenomanian beds elsewhere in northern Africa. The type species, C. saharicus, was based originally on a pair of isolated teeth from Algeria, to which was referred a partial skull and skeleton from Egypt. All of this material was either lost or destroyed more than 50 years ago. Thus, a neotype is designated for C. saharicus, a well-preserved cranium from the Kem Kem beds in Morocco. Newly discovered material from Niger is distinct from that of C. saharicus, justifying the erection of a distinct southern species. C. iguidensis, n. sp. is represented by cranial (maxilla, braincase, dentary, lacrimal, teeth) and postcranial (vertebrae) remains and grew to the same large body size as C. saharicus. The skull displays several autapomorphies, including a laterally reduced external antorbital fossa, a maxillary anteromedial process that is broadly arched toward the midline, a prominent horizontal crest on the medial aspect of the maxilla, and a deeply invaginated fossa on the laterosphenoid. Unlike C. saharicus the ventral rim of the external antorbital fossa does not protrude laterally, the anteromedial process does not demarcate a deep ventral fossa, and the frontal-lacrimal suture is not elevated. The new material provides evidence of differentiation among Cenomanian-age faunas from the Sahara and supports a close relationship between Carcharodontosaurus, Giganotosaurus, and Acrocanthosaurus.

Genetic and morphological differentiation of Mosor rock lizards, Dinarolacerta mosorensis (Kolombatović, 1886), with the description of a new species from the Prokletije Mountain Massif (Montenegro) (Squamata: Lacertidae)

A new species of lacertid lizard of the genus Dinarolacerta is described from the Prokletije Mountain Massif, Montenegro. This new species, Dinarolacerta montenegrina sp. nov., is characterized by its relatively small size, by usually having only one postnasal scale on one or on both sides of the head, a relatively lower number of temporal and postocular scales and a relatively high number of ventral scales. Osteologically, it is mainly characterized by the complete absence of the anteromedial process in the postocular bone, and more reduced supraocular osteoderms. The phylogenetic analysis using partial sequences of the mitochondrial 12S rRNA gene supports the specific status of D. montenegrina sp. nov. and shows that it represents an old independent lineage that separated from its sister species, D. mosorensis, in the late Miocene. The Morača river canyon may have acted as a geomorphological and climatic barrier causing the speciation between the two species of Dinarolacerta. The discovery of this new species endemic to the Balkan Peninsula highlights the importance of the Dinarides as one of the main European hotspots of biodiversity. This high level of endemicity in the Dinaric region is probably the result of both its geographic situation and its complex geological history and morphology.

Arthroscopic Resection of the Calcaneonavicular Coalition or the “Too Long” Anterior Process of the Calcaneus

Calcaneonavicular coalition and the “too long” anterior process (TLAP) of the calcaneus can manifest as lateral foot pain, peroneal spastic flatfoot, and repeated ankle sprain. Surgical resection of the bone bar is frequently required. We present here an arthroscopic approach that can be used to accurately assess pathoanatomy and resect the bone bar. A portal is established slightly dorsal to the angle of Gissane. This is the primary visualization portal. The working portal, which is identified under an image intensifier, is located at the space between the talonavicular and calcaneocuboid joints, directly over the TLAP or the calcaneonavicular coalition. With the 2.7-mm 30° arthroscope placed at the primary visualization portal, soft tissue around the TLAP or the calcaneonavicular coalition is cleared up with the use of an arthroscopic shaver at the working portal. After the TLAP or the calcaneonavicular coalition is clearly visualized, it can be resected with an arthroscopic burr through the working portal. The bone bar is resected proximally until the medial side of the calcaneocuboid joint, the lateral side of the taloavicular joint, and the plantar-lateral aspect of the talar head are clearly seen. Inversion stress should then be applied to the foot to prevent further impingement of the anteromedial process of the calcaneus to the plantar-lateral part of the talar head.