The amphipod genus Alexandrella (Amphipoda,Stilipedidae): taxonomic status,allometric growth and description of two new species

Two new species of the genus Alexandrella are described: A. mandibulata and A. martae. One species, A. mixta, is considered a junior synonym of the type species A. dentata. The genus now comprises six species, all of which are restricted to either the Antarctic or sub‐Antarctic region or the South Pacific. Oostegites are observed to be present on pereopod 1 in two Alexandrella species. This is a novel morphological trait among the Amphipoda. Developmental information is presented for two other Alexandrella species, in which the mandibular incisor is seen to be modified from strongly toothed in marsupial young to totally smooth in mature specimens. Also the armature dorsally on their body and the morphology of the telson undergo conspicuous allometric changes. A key to all known Alexandrella species is provided.     

Age,body size and growth pattern of Argenteohyla siemersi pederseni (Anura: Hylidae) in northeastern Argentina

In this study we analysed the body size, age structure, age at maturity, longevity and growth pattern of Argenteohyla siemersi pederseni in north-eastern Argentina using skeletochronological methods. Body size was sexually dimorphic; females were significantly larger and heavier than males, regardless of age. As A. s. pederseni is an explosive breeder with only one reproductive episode per year, we assumed that each Line of Arrested Growth (LAG) observed was equivalent to one period of decreasing growth, LAGs reflecting a direct estimation of individual age. The minimum number of LAGs counted was two for males and three for females, but there was no sexual difference in longevity. The von Bertalanffy's growth coefficients (K) were higher in males than in females for both size and body mass. Females had a lower growth rate than males, took longer to reach the minimum maturation size, and were older and larger at reproduction.     

Barrels and pagodas: clarifying the identity and variability of two nominal taxa of carinated land snails in the genus Plagiodontes (Gastropoda: Orthalicidae: Odontostominae)

Plagiodontes weyenberghii (Doering, 1877 Doering, A. 1877. [“1875”]. Apuntes sobre la fauna de moluscos de la República Argentina (continuación). Periód Zool, 2: 219–259.  [Google Scholar]) has a shell with a strong suprasutural keel; the species inhabits a restricted area in Central Argentina. Plagiodontes weyenberghii minor (Parodiz, 1939 Parodiz, JJ. 1939. Revisión de Plagiodontes y Scalarinella (Odontostominae). Physis, 17: 711–734.  [Google Scholar]) was described as a subspecies with obese shells and broader geographic distribution; some populations were sympatric with Plagiodontes daedaleus (Deshayes, 1851). A discriminant analysis on 244 adult shells combined with original information on the internal anatomy confirmed the distinctiveness of P. weyenberghii weyenberghii, whereas P. weyenberghii minor showed a broad overlap with P. daedaleus and no evidence of anatomical differences. As a consequence, P. weyenberghii minor is considered a junior subjective synonym of P. daedaleus daedaleus (Deshayes, 1851). Plagiodontes weyenberghii (Doering, 1877 Doering, A. 1877. [“1875”]. Apuntes sobre la fauna de moluscos de la República Argentina (continuación). Periód Zool, 2: 219–259.  [Google Scholar]) has unique characteristics such as the weak vascularization of the pallial system, the relative size of the penial papilla and its accessory lobe, the markedly swollen distal portion of the bursa copulatrix duct, the spermoviduct with two whorls, and the vagina with a medial depression.     

A new species of Plagiodontes from Argentina,and new data on the anatomy of four other species in the genus (Gastropoda: Orthalicidae,Odontostominae)

Abstract

Plagiodontes weyrauchi sp. nov. is among the smallest species in the genus Plagiodontes (Doering, 1877). Statistical multivariate analyses confirmed its distinctiveness from other species, mostly because of its high number of whorls (8–9.75), relatively small width, and low proportions of last whorl and aperture length to shell length; multivariate discriminant analysis applied to this species and its most similar relative, P. multiplicatus parvus, correctly identified 100%?of specimens. Pallial and genital anatomy supports P. weyrauchi as a different species, mainly because of the position of the ureteric pore, the small general size of the genital system, the presence of an accessory lobe alongside the verge, and the vaginal internal structure. Internal anatomy of four other small-sized taxa in the genus was studied. Two of them have a verge with no accessory lobe [P. dentatus (Wood, 1828) and P. patagonicus (d'Orbigny, 1835)], while the remaining two have an accessory lobe with different characteristics [P. rocae Doering, 1881 and P. multiplicatus parvus (Hylton-Scott, 1952 Hylton-Scott, M I. 1952. Nuevos moluscos terrestres del norte argentino. Acta Zool Lilloana., 10: 5–29.  [Google Scholar])]. Internal structure of the vagina also shows specific differences among Plagiodontes species; their phylogenetic significance will be further investigated.     

Male size and territoriality in the cicada killer wasp Sphecius speciosus (Hymenoptera: Crabronidae)

Males of the eastern cicada killer wasp, Sphecius speciosus, occupy territories in which they may hover or where they may perch either in trees near one or more emergence holes or on the ground at these spots from which females may emerge. Large males are more likely to hold and defend these territories at a site in northern Virginia. When resident males were captured, held and weighed, the males that replaced them, which were also captured, held and weighed, had significantly lower body weights on average than the residents.     

Microhabitat selection in the sand recluse spider (Sicarius thomisoides): the effect of rock size and temperature

In spiders, temperature is considered an important environmental variable for microhabitat selection. In this study, we evaluated the effect of temperature and rock size on the presence of the sand recluse spider Sicarius thomisoides and the degree of selectivity in different locations. This species is a large spider that lives under rocks in desert and semi-desert climates and is particularly active during the summer. In Chile, these spiders can be found at both coastal and inland locations under different thermal conditions, where usually the temperatures are lower near the coast. If large-scale climatic conditions are important for this species, they may be expected to select lower rock temperatures on the coast than at inland locations. In addition, we would expect that the spiders would choose larger rocks in inland compared to coast locations, which reduce the effect of high temperatures. We found that the probability of finding individuals of this species increased according to rock temperature and rock size in the field. Our results suggest that S. thomisoides prefers larger and warmer rocks to shelter under during the day, this selectivity being similar at both coastal and inland locations. Thus, this species tends to select rocks with the same thermal and structural conditions, independent of the climatic conditions.     

The structure and function of the tarsus I sensillar field in mites of the genus Halarachne (Halarachnidae: Gamasida)

The sensillar field on tarsus I of Halarachne (Halarachnidae: Gamasida), a respiratory tract endoparasite of seals (Pinnipedia) is associated with 12 hair- or peg-like receptor sensilla in the larva and 13 or 14 in the adult. These include thermo-hygroreceptors, each with a double wall traversed by 3 or 4 slit-like pores (dw/WP-sensilla), olfactory chemoreceptors of small inorganic molecules, each with a single wall spanned by several small and simple pores (sw/WP-sensilla), gustatory chemoreceptors with a single terminal pore (TP-sensilla), and aporous NP-sensilla which have thermoreceptive and/or other unknown functions. Some sensilla are sessile and others socketed, the latter having a possible additional/alternative mechanoreceptive function. One mechanoreceptor is a probable trichobothrium-like vibration receptor which has not been previously described in the Anactinotrichida. This range of sensilla combined with the absence of sw/WP-sensilla, i.e. olfactory chemoreceptors covered with numerous, large centrally-plugged pores, suggests that although Halarachne spp. can locate large endothermic animals, they lack the ability to discriminate between different species.     

The first record of the genus Vejdovskybathynella Serban and Leclerc, 1984 (Syncarida,Bathynellacea, Bathynellidae) in the Iberian Peninsula: three new species

Three new species of the genus Vejdovskybathynella are described from caves in northern Spain. It is the first time that this genus has been documented in the Iberian Peninsula. Vejdovskybathynella edelweiss n. sp. has several unique features: the setal formula of the antenna (0/2+exp/2+0/1+0/0+0/2+2/4); the form of the segments and claws of the mandibular palp of the mandible of the male; exopod of the female thoracopod VIII similar in size to the endopod (exopod is always longer than the endopod); small frontal projection of the basipod of the male thoracopod VIII, large or very large is common; the form and size of the lobes of the male thoracopod VIII is unique; the second spine of the furcal rami 2.5 times longer than the first spine. Vejdovskybathynella caroloi n. sp. has a unique male thoracopod VIII with a spur in the exopod that is a feature unknown in the genus, and additionally, this species has the smallest endopod of the thoracopod VIII male of the entire genus; the presence of three aesthetascs in segments VI and VII of the antennule had not been observed in this genus until now; the form of the segments of the mandibular palp of the mandible of the male are unique; the distal spine of the sympod of the uropod is larger than in other species, whereas in the rest of the species of the genus they are equal in size. Vejdovskybathynella pascalis n. sp. is the smallest species of the genus and has two and three aesthetascs in segments VI and VII of the antennule, respectively; it is the only species of the genus that has one seta on segment I and two setae on segment IV of the antenna; it has a unique male thoracopod VIII with a small spur on the frontal projection of the basipod and with the endopod larger than all other species in spite of its small size; the basal spine of the sympod of the uropod is smaller than the other three.     

The taxonomy and biology of a new species Pontonema (Nematoda,Oncholaimidae) dominant in organically polluted sublittoral sediments around Scotland,with a review of the genus

A new species of free living marine nematode, Pontonema alaeospicula sp. nov., is a dominant member of the fauna in three organically polluted sublittoral habitats off the Scottish coast. The species is described and the genus reviewed. A schematic pictorial key to the genus is provided. Some notes on the biology of P. alaeospicula sp. nov. are given, based on initial studies of the population in situ and in laboratory culture.     

The bryozoan genus Conopeum (Electridae) in New Zealand,with description of a new species and discussion of the morphological and genetic characters of Conopeum seurati (Canu, 1928)

ABSTRACT

The status of Conopeum Gray, 1848 in New Zealand is clarified, confirming the presence of three living species – one a naturalised alien, one new to science, and a third that is also known in the Pleistocene. Conopeum seurati (Canu, 1928), a Mediterranean-European species, is naturalised at three localities in New Zealand – Opua, Whangarei Harbour and Whanganui Inlet. Conopeum antipodum n. sp., previously confused with C. seurati, is an estuarine species distributed from Kaipara Harbour to Lyttelton Harbour and is also found in Te Whanga Lagoon at Chatham Island (all New Zealand localities). Conopeum oretiensis Uttley, 1951, first described from Foveaux Strait, is known as far north as Kaipara and Manukau Harbours and is known as a Pleistocene fossil from Napier, New Zealand. There is one other solely fossil New Zealand species – Plio-Pleistocene Electra ongleyi Brown, 1952 is transferred to Conopeum. Sequence data from the 18SrDNA locus confirm that Conopeum antipodum n. sp. is resolved within Conopeum and is distinct from C. seurati.

http://www.zoobank.org/urn:lsid:zoobank.org:act:4FED6730-1C70-4420-B1DA-F1D9046221DF http://www.zoobank.org/urn:lsid:zoobank.org.pub:5C130A99-0869-44A2-885C-338005FBCE07