Rounded Posterior Margin Research Articles

Population variation and sexual dimorphism in the deep-sea crab Parilia alcocki (Brachyura, Leucosiidae)

ABSTRACT Parilia alcocki is a deep-sea crab inhabiting the continental shelves and slopes of the eastern Arabian Sea and western Bay of Bengal at a depth of 128–457 m. No published information is available on its population characteristics and sexual dimorphism. The present study provides the first-ever insight into the population differentiation and sexual dimorphism in P. alcocki using Geometric Morphometric Analysis (GMA) of carapace and chela shapes. The Arabian Sea population possessed carapaces with a more pointed anterior and a rounded posterior margin as compared with the Bay of Bengal population. When chela shapes are compared, the Arabian Sea crabs possess an elongated, narrower arm, and shorter pollex. The observed shape variations could be attributed to heterogeneous habitat conditions in these regions which influence feeding and predation. Sexual dimorphism in carapace shapes was indiscernible. However, males exhibited wider intra-specific variations in carapace shape and show a larger average and maximum size for linear carapace measurements. Also, male crabs possess elongated and narrow arms and shorter pollex, whereas the females have a broader and shorter arm and longer pollex, indicative of classical sexual size dimorphism. Our study confirmed the suitability of GMA to understand the ecological and biological characteristics and trait-habitat linkages of P. alcocki.

Description of Chaetocladius (Chaetocladius) spiridonovi sp. nov. from the Russian Arctic Region (Diptera, Chironomidae).

The male adult of Chaetocladius (Chaetocladius) spiridonovi sp. nov. is described and diagnosed based on morphological and phylogenetic data. The new species is characterized by the following features: anal point very long, almost reaching apex of gonocoxite, presence of a dorsal hump at base; inferior volsella sub-rectangular to large lobe shaped, inner and caudal margin with undulation; virga composed of 2 long spines; gonostylus massively globular with rounded posterior margin. Comparison of COI with that of other known Chaetocladius species shows a K2P genetic distances of 8.9220.31%, values well associated with interspecific variation. The barcodes of the new species were identical to that of Chaetocladius sp. 7ES in BOLD systems. Molecular data were also used for the reconstruction of the phylogenetic relationships within the subgenus Chaetocladius.

A new nektaspid euarthropod from the Lower Ordovician strata of Morocco

AbstractNektaspids are Palaeozoic non-biomineralized euarthropods that were at the peak of their diversity during the Cambrian Period. Post-Cambrian nektaspids are a low-diversity group with only a few species described so far. Here we describeTariccoia tazagurtensis, a new species of small-bodied nektaspid from the Lower Ordovician Fezouata Shale of Morocco. The new species differs from the type (and only other known) species from the Ordovician strata of Sardinia (Italy),Tariccoia arrusensis, in possessing more pointed genal angles, a cephalon with marginal rim, a pygidium with anterior margin curved forwards, a rounded posterior margin, and longer and more curved thoracic tergites. The two specimens ofT. tazagurtensissp. nov. show remains of digestive glands that are comparable to those seen in the Cambrian nektaspidNaraoia. The rare occurrence ofT. tazagurtensissp. nov. in the Fezouata Shale and the distribution of other liwiids suggest that these liwiids were originally minor members of open-marine communities during the Cambrian Period, and migrated into colder brackish or restricted seas during the Ordovician Period.

Palaemonella shirakawai, a new species of shrimp (Crustacea: Decapoda: Palaemonidae), associated with burrow dwelling opistognathid fish from the Ryukyu Islands, Japan

A new palaemonid shrimp, Palaemonella shirakawai sp. nov., is described and illustrated on the basis of a single ovigerous female specimen captured from the Ryukyu Islands, Japan. It appears closest to P. aliska Marin by sharing the median carina of the carapace armed with dorsal rostral teeth extending posterior to the level of the hepatic tooth, but is immediately differentiated by the shorter rostrum, a rounded posterior margin of the telson, an elongate antennal scaphocerite with a truncate distal margin of lamella, and the longer second pereiopod. The present new species is an associate of burrow dwelling fishes belonging to the family Opistognathidae.

Two new Actinopterygii (Vertebrata, Osteichthyes) with cosmine from the Bear Gulch Limestone (Heath Fm., Serpukhovian, Mississippian) of Montana USA

ABSTRACT. The osteology and histology of two new actinopterygians, Paphosiscus circulocaudus new genus and species, and P. scalmocristus new species, are described from the Upper Mississippian Serpukhovian Bear Gulch Member of the Heath Formation of Montana (USA). These small fish (ca 50–58mm standard length) exhibit head bones and scales with cosmine, the first report of this in any actinopterygian. Other features of Paphosiscus are dorsal, anal and caudal fin margins round posteriorly, dorsal fin long with horizontal dorsal margin and achieving its greatest height immediately before its rounded posterior margin, tall unpaired predorsal ridge scales/fulcra, premaxillae not sutured to other bones, single postrostral bone, one otic canal bone (dermopterotic), dermosphenotic absent as distinct bone, mandibular articulation level with mandibular tooth row, a coronoid process, marginal teeth pleurodont, coronoid teeth with blunt crowns on a single coronoid bone. Species differ in size and features of cranial ...

A New Abdominally Parasitizing Bopyrid, Anisarthrus okunoi sp. nov. (Crustacea: Isopoda), Infesting the Hinge-Beak Shrimp Rhynchocinetes uritai Kubo, 1942 (Crustacea: Decapoda: Rhynchocinetidae)

Anisarthrus okunoi sp. nov., an abdominal parasite of the hinge-beak shrimp Rhynchocinetes uritai Kubo, 1942, is described from Awaji Island, central Japan. The new bopyrid, the second species of Anisarthrus, is distinguished from A. pelseneeri Giard, 1907 from Boulogne, France, by the lateral plates of the concave side being smaller than those of the convex side, the large, lanceolate pleopods 1–2 and slightly bilobed pleopods 3–4, the simple, bulbous pleotelson in the female, the lack of eyes, and the rounded posterior margin of the pleotelson in the male. This is the first record of bopyrid infestation of any member of the family Rhynchocinetidae in the world.

New genus of opecoelid trematode from Pristipomoides aquilonaris (Perciformes: Lutjanidae) and its phylogenetic affinity within the family Opecoelidae.

Bentholebouria colubrosa gen. n. et sp. n. (Digenea: Opecoelidae) is described in the wenchman, Pristipomoides aquilonaris (Goode et Bean), from the eastern Gulf of Mexico, and new combinations are proposed: Bentholebouria blatta (Bray et Justine, 2009) comb. n., Bentholebouria longisaccula (Yamaguti, 1970) comb. n., Bentholebouria rooseveltiae (Yamaguti, 1970) comb. n., and Bentholebouria ulaula (Yamaguti, 1970) comb. n. The new genus is morphologically similar to Neolebouria Gibson, 1976, but with a longer cirrus sac, entire testes, a rounded posterior margin with a cleft, and an apparent restriction to the deepwater snappers. Morphologically, the new species is closest to B. blatta from Pristipomoides argyrogrammicus (Valenciennes) off New Caledonia but can be differentiated by the nature of the internal seminal vesicle (2-6 turns or loops rather than constrictions), a longer internal seminal vesicle (occupying about 65% rather than 50% of the cirrus sac), a cirrus sac that extends further into the hindbody (averaging 136% rather than 103% of the distance from the posterior margin of the ventral sucker to the ovary), and a narrower body (27% rather than 35% mean width as % of body length). A Bayesian inference analysis of partial sequence of the 28S rDNA from Neolebouria lanceolata (Price, 1934), Cainocreadium lintoni (Siddiqi et Cable, 1960), Hamacreadium mutabile Linton, 1910, Opecoeloides fimbriatus (Linton, 1910), Podocotyloides brevis Andres et Overstreet, 2013, the new species, and previously published comparable sequences from 10 opecoelid species revealed two clades. One clade includes deep-sea (> or = 200 m) and freshwater fish opecoelids + Opecoeloides Bremser in Rudolphi, 1819, and a second clade included those opecoelids from shallow-water marine, perciform fishes.

Four new species of <i>Pycnophyes</i> (Kinorhyncha: Homalorhagida) from Korea and the East China Sea

Four new species of Pycnophyes are described from Korean waters and the East China Sea. Pycnophyes pardosi n. sp. is distinguished from other congeners by the presence of a single paradorsal seta on segments 2-8 and a pair on segment 9, combined with the presence of longitudinal cuticular thickenings on the dorsal and ventral sides of segment 10. Pycnophyes chalgap n. sp. is easily distinguished by the shape of its midsternal plate with the rounded posterior margin, extending beyond and overlapping half of the following segment. Pycnophyes cristatus n. sp. is recognized by its lack of ventromedial setae on segments 3-6 combined with the presence of pointed middorsal processes that turn progressively longer towards the posterior segments from segment 6. The process on segment 10 is conspicuously long, extending beyond the posterior margin of segment 11. Pycnophyes smaug n. sp. is distinguished by its general scarcity of setae which, with the exception of those in lateroventral positions, only appear in laterodorsal positions on segments 2 and 9 and in ventromedial position on segment 9. The description of four additional species brings the total number of valid kinorhynch species around the Korean Peninsula up to 26.

Blaszakia, a New Genus of Quill Mites (Acari: Syringophilidae) Parasitizing Turacos (Aves: Musophagiformes)

Abstract. A new genus and two new species of quill mites (Acari: Syringophilidae) are described and figured from birds of the order Musophagiformes. Blaszakia gen. nov. differs from the closely related Charadriphilus Bochkov et Chistyakov, 2001 by the rounded posterior margin of the stylophore and small number of chambers in the peritremal branches. The first new species — B. tauracos sp. nov. was recorded from Tauraco livingstoni (Gray) from Tanzania and from T. schalowi (Reichenov) (Musophagidae) from Guinea, the second — B. rossae sp. nov. was recorded from Musophaga rossae Gould (Musophagidae) from the Democratic Rep. of Congo. Syringophilid mites are recorded from birds of this order for the first time.

A New Genus of Ischnocera (Mallophaga)

Medium-sized Ischnocera. Head large with expanded temples. Wide hyaline margin which originates at the distal end of marginal carinae. Dorsal anterior plate of forehead with rounded posterior margin, and prolonged into a thickened posterior point. Ventral carina fused to distal end of marginal carina on each side. Pulvinus wide and attached to edges of ventral carinae. Ventral anterior plate and gular plate absent or indistinct. Anterior dorsal setae, preantennal setae, and post nodal setae elongated. Antennae similar in the two sexes. Tergal plates of abdominal segments separated medianly. Median chaetotaxy of tergal plates with thick flattened setae. Abdominal sternal plates indistinct. Terminal abdominal segment of male with rounded posterior margin. Posterior margin of female vulva with a row of small setae. Male genitalia simple, with inward curved parameres.

A NEW GENUS OF ISCHNOCERA (MALLOPHAGA)

Medium-sized Ischnocera. Head large with expanded temples. Wide hyaline margin which originates at the distal end of marginal carinae. Dorsal anterior plate of forehead with rounded posterior margin, and prolonged into a thickened posterior point. Ventral carina fused to distal end of marginal carina on each side. Pulvinus wide and attached to edges of ventral carinae. Ventral anterior plate and gular plate absent or indistinct. Anterior dorsal setae, preantennal setae, and post nodal setae elongated. Antennae similar in the two sexes. Tergal plates of abdominal segments separated medianly. Median chaetotaxy of tergal plates with thick flattened setae. Abdominal sternal plates indistinct. Terminal abdominal segment of male with rounded posterior margin. Posterior margin of female vulva with a row of small setae. Male genitalia simple, with inward curved parameres.

Dynatochela primus n. sp., n. gen. (Acarina; Laelaptidae; Iphiopsinae)

and distinctly larger than those of dorsal shield; sternal pores short, with rounded ends; margins of shield indistinct. Genitoventral shield short, with a rounded posterior margin, and with one pair of genitoventral setae, which are short, stout, and smooth, and are located near the posterior margin of the shield. Outline of anal shield not distinct on the only available specimen; only two anal setae are visible. Endopodal and metapodal shields not present. Metasternal setae distinctly smaller than sternal setae; about equal in size with genitoventral setae. Ventral body setae of about equal length with setae of dorsal shield. Peritreme very short, about two and one half times as long as it is wide. Epistome not clear in specimen examined. Chelae relatively stout. Fixed chela with a bifid tip and a large distal tooth, as well as a distal seta; bears two proximal tufts of setae. Movable chela the smaller of the two; bears one blunt tooth. Maxillary corniculi distinct; all maxillary setae smooth. All palpal setae smooth; ventrally located coxal seta is largest on palp; tarsus bears the usual bifurcate seta of the Laelaptidae. Legs relatively short and stout. Most setae on legs small, although some ventral setae, especially on coxae and tarsi, are stout and spur-like; two conspicuous spur-like setae on femur of leg I; all setae smooth.