scholarly journals Actinistian gular plates from the Cretaceous of Mexico and the problems assigning gular plates taxonomically

Fossil Record ◽  
2016 ◽  
Vol 19 (2) ◽  
pp. 101-117 ◽  
Author(s):  
Hans-Peter Schultze ◽  
Katia Adriana González-Rodríguez

Abstract. Two gular plates of an indeterminate actinistian are described from the Cretaceous of Muhi quarry, Hidalgo state, in central Mexico. Their narrow shape belongs to the few actinistian gular plates with a high length / width ratio (above 4) in contrast to most known actinistian gular plates with a length / width ratio below 4. The gulars of Muhi quarry are assigned, with caution, to the actinistian family Mawsoniidae on the basis of the length / width ratio (around 4.5) of the gular, which can be found in three other genera of the family. There are not enough characteristics in actinistian gular plates alone to erect a new genus or species. Noteworthy is the large size of the Muhi gulars that corresponds to a body length of about 1.6 m – the length of Latimeria today. The gulars are preserved in association with a basibranchial tooth plate and a few neural spines. This is the third actinistian record from the Cretaceous of Mexico.

Zootaxa ◽  
2010 ◽  
Vol 2657 (1) ◽  
pp. 55 ◽  
Author(s):  
RONALD VONK ◽  
DAMIÀ JAUME

A new genus and species of Amphipoda is reported from inland ground waters of the Sultanate of Oman. Although Glyptogidiella omanica gen. et sp. nov. exhibits several features typical of the Bogidiellidae (i. e. combined display of distinct carpal lobe on first gnathopod, reduced pleopodal rami, and unsegmented exopodite of third uropod), its exceptionally large fifth coxal plate and short rami of third uropod do not fit in the restricted diagnosis of the family as recently presented elsewhere. In fact, the enlarged coxal plate V is a feature not reported in any other amphipod, whereas no other bogidiellid displays an expanded basis on pereopod VII. The habitus of Glyptogidiella is not typical for a dweller of a true interstitial niche, with its short antennae, large coxal plate and short and stubby rami on the third uropod. This suggests that the interstitial medium could not be the primary habitat for the species, and that the underground of wadis might contain interstices of large size and could also be in contact with karstic hollows.


Zootaxa ◽  
2021 ◽  
Vol 4966 (5) ◽  
pp. 550-562
Author(s):  
JORGE PÉREZ-SCHULTHEISS ◽  
GEORGE D. F. WILSON

A new asellotan isopod of the family Protojaniridae Fresi, Idato & Scipione, 1980 is described from freshwater springs in the Osorno province, Los Lagos region, southern Chile. Wiyufiloides osornoensis gen. & sp. n. is the third South American protojanirid species and the first known groundwater isopod in Chile. The new genus and species is principally characterized by the presence of a vestigial antennal scale, a strongly subchelate pereiopod I and the absence of an apical lobe on the protopod of pleopod II. The new taxon is described in detail and figures are given. 


Zootaxa ◽  
2010 ◽  
Vol 2372 (1) ◽  
pp. 15-32 ◽  
Author(s):  
TOMOYUKI KOMAI ◽  
TIN-YAM CHAN

Two new species of alvinocaridid shrimps are described from a hydrothermal vent field off northeastern Taiwan at depths of 252–300 m. Alvinocaris chelys n. sp. is morphologically very similar to A. williamsi Shank & Martin, 2003 from the Mid-Atlantic Ridge, and A. alexander Ahyong, 2009 from the southern Kermadec Ridge. These three species can be differentiated by the shape of the postrostral ridge, telson, the second segment of the antennular peduncle and the armature of the meri and ischia of the third pereopod. The second new species, although rather similar to Alvinocaris niwa Webber, 2004 from the Kermadec-Arc, is assigned to a new genus Alvinocaridinides gen. nov., which appears to be intermediate between Shinkaicaris Komai & Segonzac, 2005 and other derived genera including Opaepele Williams & Dobbs, 1995, Chorocaris Martin & Hessler, 1990 and Rimicaris Williams & Rona, 1986. Alvinocaridinides formosa n. sp. differs from Alvinocaris niwa by completely lacking any armature on the ischia of the third to fifth pereopods and by bearing two movable spines at the posterolateral angle of the uropodal exopod. These records constitute the first discovery of the family Alvinocarididae in Taiwanese waters and represent the shallowest occurrence for alvinocaridid shrimps.


1897 ◽  
Vol 29 (11) ◽  
pp. 260-263 ◽  
Author(s):  
William H. Ashmead
Keyword(s):  

This new genus somewhat resembles Philonix, Fitch (= Actaspis, Mayr), and agrees with it in having 14-jointed antennæ, but otherwise is quite different. The head, thorax and abdomen are highly polished, impunctate, the mesonotum being entirely without any trace of the parapsidal furrows, and in this character differing widely from all other of the agamous genera of the Cynipinæ. The absence of the parapsidal furrows being peculiar only to the sexual genera Neuroterus (Ameristus, Færster) and Dolichostrophus, Ashmead. The third joint of the antennæ is not quite as long as joints 1 and 2 or 3 and 4 united, joints 10–13 a little longer than thick, while the last joint is fusiform, a little longer than the penultimate. The scutellum has a depression across its base, but is without distinct foveæ, and is also not separated from the base of the mesonotum by a delicate grooved line; apically it is obtusely rounded, shagreened and somewhat densely pubescent. The mesopleura have a large, rather deep vertical femoral impression. The wings are represented by very short pads which do not extend beyond the apex of the metathorax or just reach to base of abdomen. The abdomen is about twice as long as the head and thorax united, polished, bare; the second segment dorsally occupies about half the whole surface; the third segment dorsally is not quite as long as segments 4 and 5 united; the segments 4–7 subequal; while the hypopygium terminates in a long, pubescent spine. The hind tarsi are as long as their tibiæ, the claws being simple.


1995 ◽  
Vol 69 (2) ◽  
pp. 340-350 ◽  
Author(s):  
Francisco J. Vega ◽  
Rodney M. Feldmann ◽  
Francisco Sour-Tovar

Twenty-four nearly complete carapace samples were collected at three different localities of the Maastrichtian (Late Cretaceous) Cárdenas Formation in San Luis Potosí, east-central Mexico. The material has been assigned to five families: the Callianassidae, Dakoticancridae, Carcineretidae, ?Majidae, and Retroplumidae. Two genera of callianassid shrimp are described, Cheramus for the first time in the fossil record. Dakoticancer australis Rathbun is reported as the most abundant crustacean element; one new genus and species of carcineretid crab, Branchiocarcinus cornatus, is erected, and a single, fragmentary specimen is questionably referred to the Majidae. The three localities reflect paleoenvironmental differences, exhibited by different lithologies, within marginal marine, lagoon environments. The record of dakoticancrid crabs in the Cardenas Formation extends the paleobiogeographic range of the family and the genus Dakoticancer. Carcineretid crabs, although not abundant, seem to have been a persistent element of crustacean assemblages in clastic environments during the Late Cretaceous of the ancestral Gulf Coast of Mexico.


Remains of a fossil amphibian have been recovered from an ironstone layer in the Upper Evergreen Formation, dated as late Liassic, of southeast Queensland. Extraction of the skeleton from the very hard matrix has presented a number of problem s which are discussed. The find is an almost complete skull and mandible connected to an articulated postcranial skeleton which is missing only some ribs, the right hind leg and the distal portions of the other limbs and tail. The remains are those of a temnospondyl labyrinthodont described as a new genus and species of the family Chigutisauridae. The new form is notable for its very large size (total length estimated to be in excess of 2.5 m), relatively large marginal dentition, with unique lance-shaped tooth tips, the presence of minute denticles associated with the palate and mandible, a well developed atlas showing a strong link with the axis, neorhachitomous vertebrae that lack ossified pleurocentra and have low, heavily built neural spines, a neck region and a narrow dermal pectoral girdle associated with unreduced limbs. The discovery of this chigutisaur provides the first unequivocal evidence that labyrinthodonts survived beyond the end of the Triassic. T he status of two previously described doubtful Jurassic forms is reviewed. Austropelor Longman, 1941, from the Early Jurassic Marburg Sandstone of southeast Queensland, is confirmed as a fragm ent of temnospondyl lower jaw , probably attributable to the superfamily Brachyopoidea, and there is no longer any reason to consider the earlier suggestion that it is a reworked Triassic fossil. Cyrtura Jaekel, 1904, from the Late Jurassic Solnhofen Shale of Germany, is considered not to be a labyrinthodont, but its exact relationships are uncertain. The unsatisfactory nature of the higher taxonomy of the Temnospondyli is noted. The superfamily Brachyopoidea is reviewed and the family Kourerpetontidae is removed from it, membership of the superfamily thereby being restricted to the Brachyopidae (Late Permian to Middle Triassic) and Chigutisauridae (Early Triassic to Early Jurassic). Diagnoses for the superfamily and its two included families are provided. The relationships of the better characterized members of the two families are examined and a phylogeny based on shared derived character states is proposed. The analysis of relationships indicates that Brachyops allos Howie, 1972 shares few of the characters diagnostic of the type of Brachyops (B. laticeps Owen, 1855), and a new genus is proposed. The diversity of Australia’s brachyopoids, including the presence of the most primitive and earliest-known members of each of the included families, suggests that the superfamily originated in Australia.


Zootaxa ◽  
2021 ◽  
Vol 4966 (1) ◽  
pp. 16-28
Author(s):  
AYDIN ÖRSTAN

A new bdelloid rotifer, Coronistomus impossibilis gen. nov., sp. nov. is described from the Hawlings River in Maryland, USA. The new species is a non-swimming sediment dweller that exceeds 550 µm in body length. Its corona is a weakly bilobed ciliated field on the ventral side of the head with lateral borders continuing into mouth. The species has ramate trophi that have on each half three widely spaced major teeth with two interproximal teeth. The foot lacks spurs and ends with a pair of long, thick ventral toes and a medially positioned caudal appendage. The new species lives in microhabitats exposed to turbulent flow and its morphological idiosyncrasies are interpreted as adaptations to reduce the likelihood of getting dislodged by the water. Although the corona morphology and the caudal appendage of the new species are similar to the corresponding traits of some of the species in the family Philodinavidae, the structure of its nonprotrusible trophi and its possession of only two toes (as opposed to four) separate it from all other members of the Philodinavidae. Therefore, a new family, Coronistomidae fam. nov., is erected for the new genus Coronistomus. 


Nematology ◽  
2014 ◽  
Vol 16 (8) ◽  
pp. 953-962
Author(s):  
Oleksandr Holovachov ◽  
Sven Boström

The new genus and species Yeatesinia barbata gen. n., sp. n. is described from a sand dune habitat in New Zealand. The new genus is characterised by a body length of 299-357 μm in females and 304-361 μm in males, lip region rounded dorso-ventrally, broad laterally, dorsally inclined, lateral sides of lip region with two large, horn-like, projections, each bearing one seta at its base, each amphid surrounded by three setiform sensilla, oral opening a broad transverse slit located on the dorsal body surface, and different structure of cuticle in the dorsal and ventral body sectors. This combination of unique morphological characters clearly separates the new genus from all other members of the Plectidae. The phylogenetic affinities of Yeatesinia gen. n. and its relationships to other genera of the family Plectidae are discussed.


Insects ◽  
2019 ◽  
Vol 10 (7) ◽  
pp. 188
Author(s):  
Cristian Fernando Beza-Beza ◽  
Larry Jiménez-Ferbans ◽  
Dave J. Clarke ◽  
Pedro Reyes-Castillo ◽  
Duane D. McKenna

Mexico has the third highest diversity of passalid beetles in the World. Here we describe Tonantzin new genus, a new monotypic genus, potentially endemic to the mountains of central Mexico. The new genus is diagnosed by a new configuration of characters from the mesofrontal structure (MFS) in addition to other characters. The MFS in Passalidae has been treated either as a composite complex character or a combination of individual characters. Using a broad taxonomic sample within Proculini, we discuss the taxonomic and systematic implications of the MFS for the tribe. We define the MFS type tepetl. Given the importance of the MFS for passalid taxonomy we propose a new delimitation of the structure using boundaries based on internal and external head structures. We argue that the treatment of the MFS as a complex character better captures the nature of this structure but we ultimately find a need to standardize the way in which this structure is described in the taxonomic literature and used in phylogenetic analyses.


2020 ◽  
Vol 61 (2) ◽  
pp. 119-135
Author(s):  
Thomas Kaltenbach ◽  
Jean-Luc Gattolliat

A new genus of Baetidae, Pedicelliopsgen. nov., and a new species, P. capillifersp. nov., are described from Guinea (West Africa) based on larvae. The new genus is characterized by having strongly enlarged pedicelli and very short flagella, a brush of dense, short setae between prostheca and mola of both mandibles, a small rectangular labrum, an apicolaterally pointed maxillary palp, a labial palp with a small distolateral protuberance and long setae ventrally on glossae and paraglossae. The femora of all legs are covered with numerous long, fine setae. The patellotibial suture is absent on the fore tibia and present on middle and hind tibiae. The claw is pointed with two rows of denticles. No spines are present on the posterior margins of the abdominal tergites. The imago remains unknown and the relationships with other African genera of Baetidae remains tentative. Despite being easily identifiable and of a fairly large size (body length ca. 5 mm), only two larvae were found in two highly sampled localities in West Africa.


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