Evidence Of Sexual Dimorphism Research Articles

Sex identification in the eastern blue‐tongued lizard (Tiliqua scincoides White, ex Shaw, 1790) using morphometrics

To establish a repeatable, well-tolerated, non-invasive technique for sex identification in eastern blue-tongued lizards (Tiliqua scincoides). Measurements were obtained from 69 free living eastern blue-tongued lizards presented for treatment that were either deceased on arrival or subsequently euthanased on welfare grounds. Weight, head width (H), snout vent length (SVL) and trunk length (T) were recorded. Ratios for head width to snout vent length (H/SVL%) and head width to trunk length (H/T%) were calculated. Sex was identified at necropsy. Evidence of sexual dimorphism in this population was shown. However, the degree of difference was subtle, requiring the use of ratios in order to refine the technique. Ratios of H/SVL% and H/T% showed significant predictability with respect to sex identification in both adult and sub-adult lizards. This study established a protocol for a repeatable, non-invasive technique for sex identification in the eastern blue-tongued lizard (Tiliqua scincoides) and provides a normal reference range.

Sexual selection on skeletal shape in Carnivora.

Lifetime reproductive success of males is often dependent upon the ability to physically compete for mates. However, species variation in social structure leads to differences in the relative importance of intraspecific aggression. Here, we present a large comparative dataset on sexual dimorphism in skeletal shape in Carnivora to test the hypotheses that carnivorans exhibit sexual dimorphism in skeletal anatomy that is reflective of greater specialization for physical aggression in males relative to females and that this dimorphism is associated with the intensity of sexual selection. We tested these hypotheses using a set of functional indices predicted to improve aggressive performance. Our results indicate that skeletal shape dimorphism is widespread within our sample. Functional traits thought to enhance aggressive performance are more pronounced in males. Phylogenetic model selection suggests that the evolution of this dimorphism is driven by sexual selection, with the best-fitting model indicating greater dimorphism in polygynous versus nonpolygynous species. Skeletal shape dimorphism is correlated with body size dimorphism, a common indicator of the intensity of male-male competition, but not with mean body size. These results represent the first evidence of sexual dimorphism in the primary locomotor system of a large sample of mammals.

Accessory Slip of the Extensor Carpi Ulnaris: A Cadaveric Assessment.

Background An accessory slip arising from the extensor carpi ulnaris (ECU) tendon that inserts on the fifth metacarpal bone has been identified. We describe the frequency of this accessory slip arising from the ECU tendon and provide both qualitative and quantitative description of the slip via cadaveric examination. Methods Fifty (28 males and 22 females) cadaveric upper extremity specimens were examined after loupe-aided dissection of the dorsoulnar wrist and hand with identification of the ECU tendon. The presence of an accessory slip arising from the ECU tendon was noted. The insertion and morphology of the accessory slip was also described. Results An accessory slip arising from the ECU tendon at the level of the radiocarpal joint was found to insert on the fifth metacarpal bone in 11 (22%) specimens. Nine accessory slips inserted at the base of the fifth metacarpal (Nakashima Type A) and two inserted at the fifth metacarpal head (Nakashima Type C). Mean width of the accessory slip was 1.2 ± 0.4 mm. No evidence of sexual dimorphism was found regarding the morphology of the accessory slip. Conclusion The current study demonstrates the relative frequency and morphology of the accessory slip arising from the ECU tendon. This variant should be of diagnostic consideration in ailments of the dorsoulnar wrist and hand. Hand surgeons should be aware of this anatomic variant and its potential for clinical manifestation.

New fossil Hyaenodonta (Mammalia, Placentalia) from the Ypresian and Lutetian of France and the evolution of the Proviverrinae in southern Europe

AbstractThe proviverrines from the Ypresian (MP7–MP10) and Lutetian (MP11–MP14) are represented mainly by species recorded in the northern and central parts of Europe (Paris Basin, Belgian Basin, Germany, Switzerland). Here, we describe fossils from southern France: Saint‐Papoul (MP8 + 9; Aude) and Aigues‐Vives 2 (?MP13; Aude). One dentary with secant molars from Saint‐Papoul represents a new genus and species, Preregidens langebadrae. This taxon is possibly present in Avenay (France), the MP8 + 9 reference locality. One of the three dentaries discovered in Aigues‐Vives 2 belongs to the hypercarnivorous Oxyaenoides schlosseri, previously represented by only two isolated lower molars. This dentary appears to be the most derived of the proviverrines. This species is possibly present in Saint‐Martin‐de‐Londres (France), a locality that is considered to be close to the MP13 reference level. The two other dentaries from Aigues‐Vives 2 support the presence of Eurotherium theriodis and provide the first possible evidence of sexual dimorphism in a proviverrine species. A phylogenetic analysis of the proviverrines is performed to resolve the phylogenetic position of the three taxa. This identifies a close relationship between the new genus (Preregidens) and Oxyaenoides. The new fossils allow the age of Saint‐Papoul and Aigues‐Vives 2 to be refined: the first locality is considered to be close in age to Avenay (Ypresian; France), while the second one seems to be close to Egerkingen γ (Lutetian; Switzerland), which is considered to be possibly close in age to the MP13 reference level. Finally, the presence of O. schlosseri and E. theriodis in the southern part of France is compatible with the hypothesis that the mammals involved in the first intra‐Eocene turnover migrated northwards.

Osteology and Cartilaginous Elements of Trilepida salgueiroi (Amaral, 1954) (Scolecophidia: Leptotyphlopidae).

Morphological and anatomical studies on the Leptotyphlopidae have increased in the past 10 years, providing important data on the systematics of this group, mainly focused on the skull and lower jaw morphology. However, most studies are based on a single specimen, rarely combining more than one single method of assessing morphological information. Therefore, several data on postcranial morphology, sexual dimorphism, and ontogenetic and intraspecific variation of leptotyphlopids remain poorly understood. Herein, we provide a detailed description of the cranial and postcranial skeleton of Trilepida salgueiroi based on more than 20 specimens (including males, females and juveniles), as well as a description of osteology and cartilaginous elements through the use of combined methodologies such as X-ray scanning, high resolution CT-scanning, and clearing and staining of articulated and disarticulated specimens. We also provide data on the presence/absence of dimorphic and intraspecific variation of the observed characters. The presence of a statolithic mass in the cavum vestibuli differs from the pattern found in other scolecophidians. A correlation of dorsal vertebrae with ventral and subcaudal scales was found (1:1), as well as total number of vertebrae with middorsal scales (1:1), thoracolumbar vertebrae and ventral scales (1:1), and a higher number of caudal vertebra with subcaudal scales (1.23:1). Intraspecific variation was found in several elements of the skull, lower jaw, pelvic girdle and vertebral number, but no evidence of sexual dimorphism was found in any of the species characters analysed. The homologies of several elements are discussed, although still remaining poorly understood and unknown.

New Species of Praepusa (Carnivora, Phocidae, Phocinae) from the Netherlands Supports East to West Neogene Dispersal of True Seals / Новый вид Praepusa (Carnivora, Phocidae, Phocinae) из Нидерландов, подтверждающий распростра- нение настоящих тюленей в неогене с востока на запад

AbstractExamination of new fossils (humerus and sacrum) from The Netherlands reveals morphologically-distinctive characters, allowing the description of a new Late Miocene - Early Pliocene representative (Praepusa boeska sp.n.) of the subfamily Phocinae. Diagnostic humeral differences in shape of the coronoid (oval in males vs triangular in females) and depth of the olecranon fossae (shallow in males vs deep in females), as well as the presence of a rounded first ventral foramen and thick lateral wall in the male sacrum, reveal the first evidence of sexual dimorphism in the genus Praepusa. The newly described species adds information on the distribution of true seals, supporting the westward dispersal of this genus across the Paratethys. Strong endemism from closure of the Paratethys, and climatic, geological and stratigraphic diff erences indicate that Praepusa first inhabited the Eastern Paratethys (Early - Middle Miocene, 16.5-13.6 Ma) before dispersing to the Central (Middle Miocene, 13.6-11.2 Ma) and, later, Western (Late Miocene - Early Pliocene, 11.6-3.6 Ma) Paratethys. The Pr. boeska fossils are the youngest to date and have been found the furthest west of any previously described material of this genus. These findings help explain the origin and dispersal among described species of the genus Praepusa in comparison with other genera of the subfamily Phocinae.

Evidence for unusual size dimorphism in a fossil ailurid

A second nearly complete skeleton of the fossil ailurid Pristinailurus bristoli was recently recovered from the Hemphillian (late Miocene) Gray Fossil Site of northeast Tennessee. It appears to be significantly larger than the previously known skeleton of P. bristoli, which was surprising as the living red panda Ailurus fulgens is thought to be generally monomorphic, including between sexes. Here the presence of significant size difference in the geometric means of cranial and postcranial measurements and canine area in the two specimens of P. bristoli is tested relative to the distribution of size differences in intersex and intrasex pairs of A. fulgens. The presence of sexual dimorphism in these dimensions is also assessed in A. fulgens using t-tests. We report the first evidence of sexual dimorphism in both upper and lower canine area in A. fulgens. We also found evidence of significantly greater body size difference in the two specimens of P. bristoli than that present in A. fulgens. This could reflect a variety of causes, including the presence of multiple species or subspecies, a greater range of ecologically driven variability, or the presence of sexual dimorphism. We argue tentatively for sexual dimorphism as the most plausible explanation for the apparent size range of P. bristoli. Ethan L. Fulwood. Department of Anthropology, University of Tennessee, Knoxville, Tennessee 37865 USA Current Address: Department of Evolutionary Anthropology, Duke University, Durham, North Carolina 27708 USA ethan.fulwood@duke.edu Steven C. Wallace. Department of Geosciences, Don Sundquist Center of Excellence in Paleontology, East Tennessee State University, Johnson City, Tennessee 37614 USA wallaces@mail.etsu.edu

Growth Performance of Intergeneric Mule and Hinny Ducks In a Humid Tropical Environment

This study was conducted to evaluate growth performance and carcass characteristics of intergeneric mule and hinny ducks in a rainforest environment. Result of study showed that both mule and hinny ducks had comparable hatch weight. However, mule ducklings showed marked increase in body weight up to 6weeks. Thereafter, the hinny ducklings outperformed the mule ducks finishing with 2237.50±56.09 g for drakelets and 2065±36.32 g for ducklets while mule drakelets had 2065±36.32 g and ducklets had 1460.00±30.30 g. It was evident in this study that intergeneric hybrid mule and hinny ducklings grew fast attaining desirable market weight at 10 weeks of age and both hybrids dressed out more than 80% meat at this age. The mules showed uniform body development in both sexes, while the hinnies manifested evidence of sexual dimorphism with the males having higher body weight and higher linear body parameters than the females. The hinnies also showed some juvenile characteristics indicating that they needed more than 10 weeks to mature unlike the mules which appeared well-finished at this age.

Circulating adiponectin and cardiovascular mortality in patients with type 2 diabetes mellitus: evidence of sexual dimorphism.

BackgroundThe pathogenesis of cardiovascular (CV) mortality, whose rate is increased in type 2 diabetes, is poorly understood.While high serum adiponectin is associated with increased CV mortality in the general population, no data are available in type 2 diabetes.We here investigated whether this counterintuitive association was observable also in diabetic patients and whether it was sex-specific.MethodsThree prospective cohorts were analyzed: 1) Gargano Heart Study (GHS; 359 patients, 58 events/1,934 person-years; py); 2) Health Professional Follow-up Study (HPFS; 833 men, 146 events/10,024 py); 3) Nurses’ Health Study (NHS; 902 women, 144 events/15,074 py).ResultsIn GHS serum adiponectin predicted CV mortality in men (hazard ratio, HR, and 95% CI per standard deviation, SD, increment = 1.54, 1.19-2.01), but not women (HR = 0.98, 0.48-2.01).Circulating adiponectin predicted CV mortality in men from HPFS (HR = 1.44, 1.21-1.72), but not in women from NHS (HR = 1.08, 0.86-1.35), used as replication samples. In a pooled analysis, HRs were 1.47 (1.27-1.70) in 1,075 men and 1.07 (0.86-1.33) in 1,019 women (p for HRs heterogeneity across sexes = 0.018).ConclusionsThis is the first report showing that high circulating adiponectin predicts increased CV mortality in men, but not in women with type 2 diabetes. Further studies are necessary to unravel the mechanisms through which adiponectin influences CV mortality in a sex-specific manner.Electronic supplementary materialThe online version of this article (doi:10.1186/s12933-014-0130-y) contains supplementary material, which is available to authorized users.

Evidence of sexual dimorphism in the placental function with severe preeclampsia

Preeclampsia (PE) affects 5–8% of pregnancies and is responsible for 18% of maternal deaths in the US, and for long-term complications in mother and child. PE is an inflammatory state and may influence placental function in a sex-specific manner. We determined if there is a sexual dimorphism in the placental inflammatory and apoptotic responses in preeclamptic pregnancies. Placentas were collected from normotensive and preeclamptic pregnancies with either male or female fetuses (MPE and FPE respectively) after c-section at term with no labor. Expression patterns of markers of inflammation measured by ELISA, as well as hypoxia, apoptosis and angiogenesis markers measured by Western blotting were determined in the placenta. Consistent with previous studies, an increase in inflammation, hypoxia, and apoptotic cell death was observed in PE compared to normotensive pregnancies. Levels of TNFα, IL-6 and IL-8, and HIF-1α were significantly greater, whereas the angiogenic marker VEGF was significantly reduced in MPE vs. FPE. Sexual dimorphism was also observed in the activation of cell death: the number of TUNEL-positive cells, and the expression pro-apoptotic markers PUMA and Bax being higher in MPE vs. FPE. We also found an increase in the levels of protein and DNA-binding activity of NFκB p65 in MPE vs. FPE. In summary, we show here that in preeclamptic pregnancies the placentas of males were associated with significantly higher expression of inflammatory, hypoxia and apoptotic molecules but reduced expression of a pro-angiogenic marker compared to placentas of female fetuses. We propose that the transcription factor NFκB p65 might, at least partially, be involved in sexual dimorphism during PE.

Sex and haemodynamics in pulmonary arterial hypertension

Female sex is a risk factor for pulmonary arterial hypertension (PAH), yet females have better survival than males. We sought to determine if sex was associated with baseline haemodynamics in subjects with PAH, and whether age modified these relationships. We conducted a pooled analysis from 11 randomised trials submitted to the US Food and Drug Administration. The study sample included 1211 subjects with idiopathic PAH, 25% of whom were males, and 489 subjects with connective tissue disease-associated PAH, 13% of whom were males. After multivariable adjustment, right atrial pressure was 1.36 mmHg higher (95% CI 0.44-2.27, p=0.004), cardiac index was -0.14 L · min(-1) · m(-2) lower (95% CI -0.23-0.04, p=0.01) and pulmonary vascular resistance was 1.23 Wood units higher (95% CI 0.18-2.27, p=0.02) in males compared with females. Younger males had 5.43 mmHg (95% CI 2.20-8.66, p=0.001) higher mean pulmonary arterial pressures than younger females, but these relationships were attenuated after age 45 years. In the subgroup of connective tissue disease-associated PAH, males may have had higher right atrial pressure. These findings implicate age as a modifier and provide further evidence of sexual dimorphism in PAH.

Body growth in Hawaiian monk seals

AbstractBody length and axillary girth measurements of more than 600 free‐ranging Hawaiian monk seals from 1 to 20 yr old were analyzed. Comparison of fitted von Bertalanffy growth models confirmed there is no evidence of sexual dimorphism in this species. Substantial differences in growth patterns were detected among seven subpopulations representing the species entire geographic range. The age at which seals would be expected to attain a reference length of 180 cm ranged from just over 3 yr up to almost 7 yr at the various sites. Subpopulations exhibiting slower growth have previously been found to also exhibit lower age‐specific reproductive rates. Differences in growth of seals among sites likely indicate varying environmental conditions determining growth during the time periods represented in the sampled data.

The discovery of male Potiicoara brasiliensis (Crustacea, Spelaeogriphacea) with notes on biology and distribution

The male of Potiicoara brasiliensis is reported for the first time with evidence of sexual dimorphism. Male diagnosticcharacters are described and compared with the other three species of Spelaeogriphidae. Males present differential mor-phology on both distal podomere articles of the antennula and antenna, an elongate and curved bare endopod on pleopod2, a pair of short round penes on the sternum near the base of pereopod 7, and telson with dorsum almost smooth and apexstraight. Material is sampled for the first time from karstic areas north of the species type-locality, Gruta Ricardo Franconear Corumbá City, and Gruta do Curupira in the Araras Mountains. These new findings expand the distribution of thespecies over seven hundred kilometers. Comparisons between exemplars of both sexes are presented. A hypothesis on the distributional pattern of P. brasiliensis is introduced based on the geological history of Central-West Brazil.

Modification of neurobehavioral effects of mercury by a genetic polymorphism of coproporphyrinogen oxidase in children

Mercury (Hg) is neurotoxic, and children may be particularly susceptible to this effect. A current major challenge is the identification of children who may be uniquely susceptible to Hg toxicity because of genetic disposition. We examined the hypothesis that CPOX4, a genetic variant of the heme pathway enzyme coproporphyrinogen oxidase (CPOX) that affects susceptibility to mercury toxicity in adults, also modifies the neurotoxic effects of Hg in children. Five hundred seven children, 8–12years of age at baseline, participated in a clinical trial to evaluate the neurobehavioral effects of Hg from dental amalgam tooth fillings in children. Subjects were evaluated at baseline and at 7 subsequent annual intervals for neurobehavioral performance and urinary mercury levels. Following the completion of the clinical trial, genotyping assays for CPOX4 allelic status were performed on biological samples provided by 330 of the trial participants. Regression modeling strategies were employed to evaluate associations between CPOX4 status, Hg exposure, and neurobehavioral test outcomes. Among girls, few significant CPOX4–Hg interactions or independent main effects for Hg or CPOX4 were observed. In contrast, among boys, numerous significant interaction effects between CPOX4 and Hg were observed spanning all 5 domains of neurobehavioral performance. All underlying dose–response associations between Hg exposure and test performance were restricted to boys with the CPOX4 variant, and all of these associations were in the expected direction where increased exposure to Hg decreased performance. These findings are the first to demonstrate genetic susceptibility to the adverse neurobehavioral effects of Hg exposure in children. The paucity of responses among same-age girls with comparable Hg exposure provides evidence of sexual dimorphism in genetic susceptibility to the adverse neurobehavioral effects of Hg in children and adolescents.

Abstract MP067: Six Novel Loci With Evidence For Sexual Dimorphism For Human Anthropometric Traits From Genome-wide Meta Analyses Across 270,722 Individuals

Height, adiposity, and fat distribution differ in men and women and, in part, may explain sex differences in susceptibilities to complex diseases like cardiovascular disease. Genome-wide association studies (GWAS) of these traits have previously reported sexually dimorphic associations, yet studies have primarily been limited to interrogation of variants with genome wide significant main effects only. Because of these biological differences by sex and as there is growing interest in the study of gene-environment interactions in the context of GWAS in general, we conducted sex-specific meta-analyses of 9 phenotypes: height (HT), weight (WT), body mass index (BMI), waist circumference (WC), hip circumference (HIP), WC/HC ratio (WHR), WC adjusted for BMI (WCadjBMI), HC adjusted for BMI (HCadjBMI), and WHR adjusted for BMI (WHRadjBMI). In the discovery stage, we performed sex-specific meta-analyses of 46 GWAS, comprising 60,586 men and 73,137 women. Each study used an additive model to test up to ∼2.8M imputed SNPs for association with inverse-normal transformed phenotypes. From our first scan based on the sex-specific association P-values (P women , P men ) across all phenotypes, we selected 619 independent SNPs at a false discovery rate (FDR) of 5% to take forward to replication. We also conducted a second scan based on the P-value for sex difference (P sex-diff ) with better power to detect signals of opposite effect direction, yet we did not detect any signal at FDR of 5%. Follow-up of the 619 SNPs in up to 62,395 men and 74,657 women, many of which were genotyped on Metabochip, a custom Illumina iSelect array to which we submitted sex-specific SNPs, resulted in 205 loci with genome-wide significanct (P women or P men < 5x10 -8 ) p values in the combined discovery and follow-up analysis. For those 205 loci, we found 4 loci with significant (P sex-diff < 0.05/205) and 14 loci with suggestive (P sex-diff <0.05) evidence for sex-difference including known sexually dimorphic associations with anthropometric traits ( GRB14 , 1q41 , VEGFA , ADAMTS9), known anthropometric trait associations without any prior evidence for sexual-dimorphism ( 14q23.1, 3q21.3, 6q14.1, 4q12, 12q24.31, SEC16B, 17q21.32 , and 13q31.3 ), and novel sex-specific associations with anthropometric traits ( 5q11.2, 5q23.1, PPARG, 2q37.1, 17p11.2 , and 5q35.1 ). Interestingly, we found that our replicated loci for WHR/WC were enriched with markers with sex-differences, and that these genetic effects were uniformly stronger in women compared to men. Collectively, these results underscore the gain from sex-stratified GWAS in order to better pinpoint the genetics of complex traits and illustrate a sexually dimorphic genetic underpinning to some of these traits. Our results more globally emphasize the need to consider gene-environment interaction when searching for genes influencing risk to complex disease.

Zygomaticomaxillary suture shape analyzed with digital morphometrics: Reassessing patterns of variation in American Indian and European populations

Typological classification of human zygomaticomaxillary suture (ZMS) shape is often used in forensic assessment of ancestry, following earlier studies reporting higher frequencies of "angled" sutures among American Indians and higher frequencies of "curved" sutures among Caucasians. In this paper we present a new method of digital morphometrics to quantify and compare ZMS shape in 60 American Indian and 60 European crania. Suture outlines were recorded as three-dimensional (3D) contours on digital models of adult male and female crania created with a portable 3D laser scanner. Each contour was represented by about four hundred point coordinates, which were transformed via Fourier analysis into amplitude coefficients suitable for use in linear discriminant analysis. Discriminant functions were created that accurately predicted group membership for 83% of the crania in the sample, after leave-one-out cross-validation. The results were compared with traditional typological classifications based on visual evaluation of ZMS shape, and the contour-based method was found to be more effective than the typological approach. However, the distribution of ZMS types within the two sample groups did not conform to previously reported patterns. This discrepancy indicates that ZMS shape may reflect not only genetic factors, but also environmental factors such as diet and stress. In addition, some evidence for sexual dimorphism in the zygomaticomaxillary complex was observed. Based on these findings, we recommend caution when using ZMS shape analysis in forensic ancestry determination.

Craniometric measures during development using MRI

Developmental changes in brain volume and shape in infants, children, and adolescents were ascertained with MRI, using craniometric (linear brain) measures in 118 individuals, ages 1 postnatal week to 18.7years. Collected clinical data included age, sex, weight, height, body mass index, occipito-frontal circumference (OFC), and diagnosis prompting the MRI scan. Twenty craniometric measures were obtained to allow for the determination of specific ratios as well as sex and age-related changes in brain shape and size. Analysis of the cohort showed that OFC is larger today than 40years ago, likely related to a concomitant increase in body stature. The data indicated a wide variation in the maturational pattern of several specific craniometric ratios, which reflects changes in the volume and configuration of the brain with advancing age. The increases in brain volume and changes in brain shape were most dramatic during infancy, with continued minor escalations in volume and reshaping during childhood and adolescence. Sex differences existed both in brain volume and shape, as well as evidence of sexual dimorphism. Changes in cerebellar volume and shape lagged behind the corresponding changes in the cerebral hemispheres. These collective data in living developing individuals allow for comparisons of clinical or craniometric measures in distant and more recent humans.

Determinación de insulina y citocinas durante el desarrollo mediante inmunoensayo múltiple: implicaciones en pediatría

Introduction Multiplexed immunoassays allow the simultaneous determination of multiple parameters from minute biological samples. Our aim was to establish the normal values of cytokines and insulin during pubertal development, as well as their relationship with adrenal and gonadal steroids. Subjects and methods Serum insulin, adiponectin, resistin, leptin, tumoral necrosis factor-α, interleukin-1β, interleukin-6 and interleukin-8 concentrations were studied in 147 healthy children (Tanner I, 18 males and 18 females; Tanner II, 17 males and 13 females; Tanner III and IV, 21 males and 19 females and Tanner V, 18 males and 23 females). The relationship of these parameters with free and total testosterone, estradiol, sex-hormone binding globulin, 17-hidroxyprogesterone, dehydroepiandrosterone sulphate, 3α-androstanediol glucuronide and Δ4-androstenedione levels were also analyzed. Results The concentrations of insulin, resistin and leptin increased during development, with higher levels found in females. Adiponectin levels did not change, although higher concentrations were also observed in femalesthan in males. Interleukin-6 and 8 increased and interleukin-1β levels decreased throughout development, without any evidence of sexual dimorphism. There are good correlations between adiponectin and sex-hormone binding globulin, as well as between leptin and Δ4-androstenedione. Conclusions Changes in these parameters seem to be related with adrenal and gonadal function. Pubertal stage and sex must be taken into consideration when these data are used.

Systématique du Gobiidae Lophogobius cyprinoides (Pallas, 1770)

Diagnosis: number of fins rays D1: VI; D2: I+ 9; C: 21–22; A: I+ 8; P: 17–18; Pv: 10; number of scales on the lateral line Ec: 27–28; number of vertebras V: 26. Evidence of sexual dimorphism is shown by two different shapes of urogenital papilla. The lateral system was observed using scanning electron microscopy after 2% glutaraldehyde fixation in sea water. The oculoscapular, preopercular canals, mucous pores are inventoried and the distribution and number of neuromasts are presented. The coding sequences for 18S ribosomic RNA are identified.

Variation in the digging apparatus of the subterranean silvery mole-rat, Heliophobius argenteocinereus (Rodentia, Bathyergidae): the role of ecology and geography

The skull of most subterranean tooth-digging rodents is markedly affected by their digging mode. In the present study, we investigated the cranial variation in a strictly subterranean, highly specialized Afrotropical tooth-digger, Heliophobius argenteocinereus (Bathyergidae, Rodentia), using a geometric morphometric approach and evaluated the effect of different factors on size and shape differences among four populations. No evidence for sexual dimorphism was found in skull size or shape. The cranial shape variation was large and influenced mainly by the type of habitat (miombo woodland versus farmland and grassland) and the latitudinal gradient. The dorsal side of the skull appears to be more plastic and adaptable to local environments, as well as more independent of size, than the ventral side. Only the shortening of the rostrum is presumably an adaptive process independent of size that leads to an increase of efficacy of the tooth-digging apparatus in Heliophobius, whereas the increase in the in-force and the more procumbent incisors both comprise size-related changes caused by ontogenetic allometric growth. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 97, 822–831.