A new species of the Genus Pelodiscus Fitzinger, 1835 (Testudines: Trionychidae) from Huangshan, Anhui, China

A new species of the soft-shelled turtle genus Pelodiscus is described based on seven specimens from Huangshan, southern Anhui Province, China. The new species, Pelodiscus huangshanensis sp. nov., is distinguished from other species in the genus Pelodiscus by the following characteristics: (1) Small size (maximum carapace length of 101.16 mm and maximum body length of 190 mm); (2) keel high; (3) tiny yellowish-white spots on the throat; (4) no black pinstripes around the eyes; (5) white longitudinal bands on both sides of the neck in juveniles, absent in adults; (6) plastron yellowish-white, and only a dark patch on each side of the armpit; (7) many tubercles on the dorsal surface, but indistinct in the center; and (8) entoplastron “⌒” shaped. The phylogenetic relationships of the species in Pelodiscus were reconstructed using the sequences of cytochrome b (cyt b) and NADH dehydrogenase subunit 4 (ND4) genes. The new species formed a monophyletic clade with strong support. The uncorrected pairwise distances between the new species and other representatives of Pelodiscus ranged from 5.4% to 9.2% for cyt b and 4.1% to 7.6% for ND4. The new species brings the number of species of the genus Pelodiscus to six; five species are distributed in China, with three species endemic to China.

Population structure of Gammarus izmirensis (Amphipoda) inhabiting Yiğitler Brook (Nif Stream, İzmir)

Yiğitler Brook, one of the branches of Nif Stream, has a regular flow regime throughout the year. The brook is one of the important aquatic habitats in terms of biological diversity by having relatively unpolluted water. The main objective of the present study is to get information about the population structure of Gammarus izmirensis Özbek, 2007 whose type locality is Yiğitler Brook. There is no information about the species in literature except its original description paper. Gammarus specimens were sampled in monthly intervals between October 2015 and November 2016. Samplings were performed at one locality. During the study, a total of 1938 G. izmirensis specimens were investigated. Of them; 850 were females, 586 were males and 502 were juveniles. The maximum body length was 14.5 mm in males and 14.0 mm in females. The number of juveniles is higher in March and August. The species has a multivoltine life cycle with two generations (spring and summer) throughout the year.

Are small fishes more sensitive to habitat loss? A generic size-based model

Habitat loss represents the greatest threat to freshwater biodiversity. The potential for life history attributes to correlate with the risks associated with habitat loss represents a possible mechanism for more effective and rapid assessments, especially in data-limited situations. Body size correlates with many other life history attributes and is a good starting point for investigating correlates with habitat loss. Here, we use a generic stage-based matrix population model, parameterized using length-based allometries, to investigate if such a mechanism exists. Our analysis revealed that small species (shorter maximum body length) were initially more sensitive to the loss of habitat. Moreover, distinct stage-based patterns exist showing an increased sensitivity of population growth rate for small species to both habitat loss and vital rate perturbations of pre-adult stages. This indicates that the pre-adult period represents a critical stage for the continued production of small species and increased importance of the conservation of habitat used by young-of-the-year and juvenile fishes.

Psyllaphorura jiangsuensis sp. nov. from China (Collembola: Onychiuridae)

The genus Psyllaphorura is reported from China for the first time. A new species, Psyllaphorura jiangsuensis sp. n. as the eighth species of the genus, is described from Nanjing, Southeast China. It is most similar to the Russian species Psyllaphorura martynovae (Stebaeva, 1985) in many respects. However, it can be distinguished from the latter by number of vesicles in the postantennal organ, number of setae on ventral tube, length ratio of unguiculus to unguis, absence of unguiculus basal lamella and maximum body length. A key to all of the species of Psyllaphorura is provided.

Spiochaetopterus nonatoi, a new species of Chaetopteridae (Polychaeta) from Brazil: biogeographical consequences

A new species Spiochaetopterus nonatoi is described from the south-eastern coast of Brazil, the type locality being Flamengo Bight, 6-m depth (23°30′S 45°06′W). This species is distinguishable from already erected species of the same genus by the following characteristics: oculate specimens of large size; maximum segments, 197 (N=15); maximum tube length, 45 cm; maximum body length, 20 cm; orange coloration of the fore part (peristomium and segment 1) and of the ventral shield on segments 6–7; shape of the specialized enlarged cutting seta on A4 with an obliquely truncated distal end; this slightly concave section is heart-shaped and clearly asymmetrical; segments B1 and B2 with one lobe on the neuropodia. This additional description in the genus Spiochaetopterus confirms the limited geographical area of each species in this genus. In spite of the probable ability of planktonic larvae of Spiochaetopterus to disseminate throughout the Atlantic Ocean, the benthic adults of each species cover only a limited geographical area. In particular, the stem species S. costarum loses its cosmopolitan character.

Estimating mean body masses of marine mammals from maximum body lengths

Generalized survival models were applied to growth curves published for 17 species of cetaceans (5 mysticetes, 12 odontocetes) and 13 species of pinnipeds (1 odobenid, 4 otariids, 8 phocids). The mean mass of all individuals in the population was calculated and plotted against the maximum body length reported for each species. The data showed strong linearity (on logarithmic scales), with three distinct clusters of points corresponding to the mysticetes (baleen whales), odontocetes (toothed whales), and pinnipeds (seals, sea lions, and walruses). Exceptions to this pattern were the sperm whales, which appeared to be more closely related to the mysticetes than to the odontocetes. Regression equations were applied to the maximum lengths reported for 76 species of marine mammals without published growth curves. Estimates of mean body mass were thus derived for 106 living species of marine mammals.

Growth and development of Gnathostoma spinigerum early third-stage larvae in vitro

Early third-stage larvae of Gnathostoma spinigerum were cultured in RPMI-1640 supplemented with 25mM NaHCO3,100 units/ml penicillin G, 100 μg/ml of streptomycin, 5 μg/ml of amphotericin B and 10% foetal calf serum at 37°C under 5% CO2 in air for 60 days. After 3 days of cultivation, the larvae moulted. Body sizes increased from 0.49 ± 0.09 × 0.07 ± 0.01 mm in length and width to 4.08 ± 0.48 × 0.32 ± 0.04 mm after 60 days of cultivation. The maximum body length and width of these larvae were 4.94 mm and 0.35 mm, respectively. The survival rate (67.5 %) of the worms was observed at the end of cultivation. The addition of foetal calf serum was found to be essential for growth and development.

A new species of Xenopus (Anura: Pipidae) from the highlands of Ethiopia

A new species of African clawed toad is described from the Bale Mountains region in southern Ethiopia. A series of small field samples indicate a maximum body length for females of about 50 mm. The new species is a 3-clawed Xenopus, distinguished by a rounded snout with relatively small eyes, a dark brown dorsal colouration lacking large spots or patches (which are common elsewhere in the genus), the absence of both a subocular tentacle and a metatarsal tubercle, and a small number of lateral line plaques (18 or 19 transverse plaques between eye and vent). The new species occurs in a region noted for the high proportion of endemic taxa in its fauna and flora; it occurs sympatrically with the single previously-known Ethiopian Xenofius, X. clivii, at around 2600 m asl., but is easily distinguished from this 4-clawed species. The new species has a chromosome number of 2n = 36; a series of biochemical and genetic studie indicate that it is most closely related to X. laevis and X. gilli and that it is relatively distant from the three species which are its nearest geographical neighbours, X. clivii, X. borealis and X. muelleri.

Correlating resting discharge with small signal sensitivity and discharge variability in primary endings of cat soleus muscle spindles

1. In a previous report we proposed that primary endings of cat soleus muscle spindles can be separated into two kinds. One kind, called by us silent endings, at muscle lengths shorter than Lm -10 (maximum body length -10 mm), fell silent after a 5 mm shortening step. Spontaneous endings, on the other hand, were able to resume a resting discharge after a brief pause at all muscle lengths down to Lm -20. This report examines further differences between the two kinds of endings. 2. There were consistent differences in the muscle length dependence of the maintained level of resting discharge of the two kinds of endings, measured after a conditioning contraction or a contraction followed by a shortening step. The resting discharge of spindles with spontaneous endings, after both forms of conditioning increased progressively with length. For silent endings, after a conditioning contraction, resting discharge fell slightly at longer lengths. 3. Discharge variability, measured at a number of muscle lengths, showed a dependence both on mean interimpulse interval and on spindle type, being higher in silent than spontaneous spindles. 4. Small signal sensitivity was measured with the use of 1 Hz sinusoidal stretches applied longitudinally to the tendon. Sine wave amplitude was adjusted to give a 30% depth of modulation of the resting discharge. Spontaneous endings were consistently less sensitive to the stretches than silent endings at all muscle lengths. Average sensitivities, measured over a range of lengths between Lm -4 and Lm -20 mm were 0.30 imp.s-1.microns -1 for spontaneous endings and 0.66 imp.s-1.microns -1 for silent endings.(ABSTRACT TRUNCATED AT 250 WORDS)