Advanced Stage Of Decomposition Research Articles

Soil Dynamics in Carbon, Nitrogen, and Enzyme Activity Under Maize–Green Manure Cropping Sequences

The diversification of cropping sequences has a positive impact on soil organic carbon, while improving nutrient cycling and crop yields. The objective of this research was to assess amylase, cellulase, C and N dynamics, and maize yield on a low fertility oxisol in the Brazilian Cerrado. The experiment was conducted under field conditions during three maize crop succession cycles. The treatments consisted of cultivating maize during the summer, after sorghum and lablab cropped as green manure and fallow during the winter. Higher maize yields were achieved by sorghum–maize succession compared to monocropping, due to higher N fertilizer and biomass inputs to topsoil. Sorghum–maize succession also provided a higher proportion of stable C and N compared to other successions. Maize yields declined as tropical soil fertility intrinsically decreased along three crops succession cycles. Cellulase activity decreased over time, whereas amylase activity increased as the plant residues were already in advanced stages of decomposition. The sorghum–maize crop succession stood out compared to lablab and fallow as it provided the highest maize yields, while maintaining higher C and N levels, and amylase activity. This better performance was likely due to larger amounts of incorporated biomass and better mineral N fertilizer management.

Comparison of identification methods used in Forensic Anthropological services in four distinct institutes in Brazil and the United States

ABSTRACT Identifying unknown deceased individuals, especially those in advanced stages of decomposition, dismemberment, or burning, is a major medico-legal challenge. Forensic anthropologists play a crucial role in these cases due to the numerous characteristics that can be derived from bone remains. Their methods help evaluate the biological profile and individual characteristics, narrowing potential matches. This research investigates the identification methods used by forensic anthropologists in Medicolegal Institutes and Medical Examiner’s Offices in Brazil and the USA. Case reports from forensic anthropology institutes in Vitória, Rio de Janeiro, Porto Velho (Brazil), and New York City (USA) were analysed. In resolved cases, details such as the biological profile, trauma, decomposition extent, and individualization markers were documented. Statistical tests evaluated the association between these variables and identification outcomes. Conventional identification methods included dental analysis, DNA testing, and fingerprint analysis. Additionally, Bayesian methods, visual identification, prosthetics, and X-ray comparison proved useful. This study highlights that forensic anthropologists can employ a variety of methodologies beyond standard practices, enhancing the identification process in complex cases.

A review of methods of age estimation based on postmortem computed tomography

Abstract Age at death is one of the key elements of the ‘biological profile’ prepared when analysing unidentified human remains. Biological age is determined according to physiological indicators and developmental stage, which can be determined by bone assessment. It is worth remembering that the researcher must interpret each case individually and in accordance with the current state of knowledge. One of the most developed tools for analysing human remains is postmortem computed tomography. This allows for the visualisation not only of bones without maceration but also of the entire body under various altered states, including corpses in advanced stages of decomposition and burnt bodies. The aim of this review is to present the current methods for age estimation based on postmortem computed tomography evaluation, comparing the results presented in 18 research projects published between 2013 and 2023 on foetuses, children, and adults from contemporary populations. Recent literature includes assessment of bones and characteristics such as skulls, teeth, vertebrae, pelvises, and long bones to estimate age at death. We cover the methods used in this recent literature, including machine learning, and discuss the advantages and disadvantages of them.

Comparative Toxicological Analyses of Traditional Matrices and Blow Fly Larvae in Four Cases of Highly Decomposed Human Cadavers.

In forensic investigation, determining the time and cause of death becomes challenging, especially in cases where the remains are found in advanced decomposition, rendering traditional toxicological samples unavailable or unreliable. Entomotoxicology, an emerging methodology within forensic science, leverages insect specimens collected from cadavers as alternative toxicological samples. Several laboratory and field research studies have highlighted the efficacy in detecting various drugs, toxins, and elements absorbed by insects feeding on cadaveric tissues, even at low concentrations. However, correlation studies between drug concentrations in conventional matrices and insects remain controversial due to unknown factors influencing drug metabolism and larval feeding activity. This paper presents four real cases in which human cadavers were discovered in advanced stages of decomposition, and toxicological analyses were performed on both insect samples and available matrices. The results presented complement the scant literature currently available on the application of entomotoxicology in real cases, providing insights into the correlation between larvae and human specimen results. Furthermore, guidelines to collect and preserve entomological evidence at the crime scene and during the autopsy for use in entomotoxicological analyses are provided. This advancement holds promise in aiding forensic investigations, particularly in cases where traditional methods cannot be applied or require supporting data for further validation.

Mineralogical Characteristics of Soils in Southern Taraba State Northeast, Nigeria

Mineralogy of fadama soils of southern Taraba state was carried alongside its influence on the soil’s physical and chemical properties. The three local government areas selected for this study were Ibi, Wukari and Donga. The mineralogical compositions of the soils were evaluated using the clay fraction. X- ray diffraction (XRD) analysis showed ibi had quartz (21%), microcline (47%) and kaolinite (25%), Wukari Tsukundi had quartz (17%), microcline (20%) and kaolinite (32%), phlogopite (15.4%) and gibbsite (23%) while Donga had mineral composition of quartz (20%), microcline (33%) and kaolinite (47%) and therefore the clay minerals are interstratified (mixed mineralogy). The soil textures in these mapping units (MUs) are sandy clay loam (SCL), loam sand (LS) and sandy loam (SL) in the Ap horizons of pedons I, 2 and 3 respectively. The subsurface horizons are Silt Loam, SCL and LS. The silt clay ratio (SCR) indicated that the soils are relatively young soils with reserved weatherable minerals, mean SCR were 1.40, 1.50 and 4.00 in pedons 1, 2 and 3 respectively. The acidity decreased as the profile depth increased and it was moderately acidic soil with pH(KCl) ranged from 5.92- 4.75 for pedons. The delta pH (\(\Delta\)pH) of the soils showed all negative values; this indicated that the soil colloids contained appreciable silicate clay minerals with relatively constant surface charge while C/N ratios indicated advanced stage of organic matter decomposition. Percentage Al saturation to the TEA stood at 15%, 19% and 9% for pedons I, 2 and 3 respectively, The exchangeable Ca constitutes above 70 % of the total exchangeable bases (TEB). The percentage base saturation (%BS), was largely dominated by exchangeable cations in moderately to very high rating and their mean values are 80%, 77% and 74% for pedons I, 2 and 3 respectively. The arrays of minerals are at different stages of weathering- quartz and phlogopite at moderate stage of weathering, microcline at minimal stage of weathering while kaolinite and gibbsite are at intense weathering stages. These minimally and moderately weathered soils are generally considered to be of good fertility status. The soils were classified as Alfisols/Entisols mix.

The influence of rehydration on decomposition in the Highveld region of South Africa-Using a pig model.

Researchers have observed that rainfall may re-initiate decomposition in desiccated tissue; however, no conclusive research-based evidence exists on the specific effects of rehydration on decomposition. Therefore, this study aimed to assess the effects of artificial rehydration on the progression of decomposition following the advanced stage of decomposition. Twelve adult pig cadavers (8 experimental; 4 controls) were placed in the central Highveld of South Africa during cooler (April-July 2021) and warmer (August-November 2021) months. Decomposition was scored approximately biweekly to obtain the total body score, and accumulated degree days (ADD) were calculated for each pig. All pig cadavers were covered by chicken wire cages with transparent tarps to control for natural rehydration and scavenging. Once the experimental pig cadavers reached a three-visit stasis in the advanced phase of decomposition, they were artificially rehydrated, and changes in the progression of decomposition between the control and experimental groups were plotted (ADD against TBS) for observation. The rehydrated experimental pig cadavers showed re-initiation of decay and insect re-colonization, while the control cadavers mainly remained in a state of stasis with insect activity ceased altogether. Greater cadaver decomposition islands and a color change post-rehydration were also noted in some experimental cadavers. This supports the need for future research on the impact of rehydration, including associated soil moisture on decomposition rates, progression, and invertebrate colonization, which will enhance our understanding of the effects these environmental factors have on the accuracy of post-mortem interval estimation.

The effect of dead standing (marcescent) biomass on litter decomposition in herbaceous flora is governed by plant functional group

Abstract In autumn, temperate herbs begin to senesce and gradually shed their litter. However, surprisingly large amounts of dead biomass remain standing, that is, marcescent. The consequences of marcescence for the decomposition of biomass once it finally reaches the soil are largely unknown. Here, we aimed to determine whether marcescence affects subsequent litter decomposition in the organic layer to such an extent that its mass loss and chemistry are distinguishable from those of directly shed biomass. We further aimed to disentangle the role of plant functional traits and groups (forbs vs. grasses) concerning the marcescence effect on decomposition. To this end, we sampled the living, marcescent and shed senescent biomass of 39 herbaceous plant species grown in a common garden experiment, determined plant functional traits and incubated the marcescent and shed plant tissues in the field in an allochthonous organic layer for 6 months. We determined the mass loss, C and N contents, chemical composition and microbial community structure of the decomposed tissues. Our results show that marcescent tissues decomposed more slowly than directly shed tissues (mass loss 37.3% vs. 63.2% for forbs, 43.5% vs. 45.5% for grasses), likely due to more favourable conditions for decomposition in the organic layer. These were reflected in a significantly higher microbial colonization of shed (~333 and 708 μg biomass C g−1 for forbs and grasses, respectively) than marcescent tissue (~189 and 543 μg biomass C g−1 for forbs and grasses, respectively) even after 6 months in the organic layer. Moreover, higher relative contributions of aliphatics and polyphenolics in shed tissues indicated a more advanced stage of decomposition. Notably, marcescent tissues of forbs, with a more complex growth architecture (being composed of stems [marcescent] and leaves [shed]), decomposed substantially more slowly than directly shed tissues. In contrast, differences in decomposition between marcescent and shed tissues of grasses, with a more uniform growth architecture, were substantially less pronounced. These findings highlight that marcescence in the temperate herbaceous flora can strongly affect litter decomposition and thus C and nutrient cycling through temperate ecosystems, but that the extent to which marcescence affects decomposition depends on plant functional group.

Fine root presence and increased phosphorus availability stimulate wood decay in a central Amazonian rainforest

In the Amazon basin, approximately 60% of rainforest thrives on geologically old and highly weathered soils, thus decomposition represents an important mechanism for recycling nutrients from organic matter. Although dead logs and branches constitute up to 14% of the carbon stored in terrestrial ecosystems, woody debris decomposition and mainly the effect of direct nutrient cycling by plant root interaction is poorly studied and often overlooked in ecosystem carbon and nutrient budgets. Here we monitored the decomposition of five different local woody species covering a range of wood density by conducting a long‐term wood decomposition experiment over two years with factorial root presence and phosphorous (P) addition treatments in a central Amazonian rainforest. We hypothesized that woody debris decomposition is accelerated by colonizing fine roots mining for nutrients, possibly strongly affecting wood debris with lower density and higher nutrient concentration (P). We found that root colonization and P addition separately increased wood decay rates, and although fine root colonization increased when P was added, this did not result in a change in wood decay. Nutrient loss from wood was accelerated by P addition, whereas a root presence effect on nutrient mobilization was only detectable at the end of the experiment. Our results highlight the role of fine roots in priming wood decay, although direct nutrient acquisition by plants seems to only occur in more advanced stages of decomposition. On the other hand, the positive effect of P addition may indicate that microbial nutrient mobilization in woody material is driven mainly by wood stoichiometry rather than priming by root activity.

Machine Learning Models for Prediction of Sex Based on Lumbar Vertebral Morphometry.

Identifying skeletal remains has been and will remain a challenge for forensic experts and forensic anthropologists, especially in disasters with multiple victims or skeletal remains in an advanced stage of decomposition. This study examined the performance of two machine learning (ML) algorithms in predicting the person's sex based only on the morphometry of L1-L5 lumbar vertebrae collected recently from Romanian individuals. The purpose of the present study was to assess whether by using the machine learning (ML) techniques one can obtain a reliable prediction of sex in forensic identification based only on the parameters obtained from the metric analysis of the lumbar spine. This paper built and tuned predictive models with two of the most popular techniques for classification, RF (random forest) and XGB (xgboost). Both series of models used cross-validation and a grid search to find the best combination of hyper-parameters. The best models were selected based on the ROC_AUC (area under curve) metric. The L1-L5 lumbar vertebrae exhibit sexual dimorphism and can be used as predictors in sex prediction. Out of the eight significant predictors for sex, six were found to be particularly important for the RF model, while only three were determined to be important by the XGB model. Even if the data set was small (149 observations), both RF and XGB techniques reliably predicted a person's sex based only on the L1-L5 measurements. This can prove valuable, especially when only skeletal remains are available. With minor adjustments, the presented ML setup can be transformed into an interactive web service, freely accessible to forensic anthropologists, in which, after entering the L1-L5 measurements of a body/cadaver, they can predict the person's sex.

Bioarchaeological investigation of WWI burials at Nowa Osuchowa, Poland

ABSTRACT During construction works in eastern Poland, the remains of 25 individuals were discovered. The site near Nowa Osuchowa was excavated in 2016 and after osteological and taphonomical analyses the remains were reburied. The remains were identified as members of the Prussian Army fighting in WWI. Radiographic imaging was employed to aide differential diagnosis of pathologies. Skeletal evidence of antemortem fractures, dislocation and infection was found. Several individuals showed evidence of perimortem fractures and high-velocity projectile trauma. Taphonomic analyses indicate that some of the individuals were buried at the location very soon after death, while others were likely already in more advanced stages of decomposition at the time of burial at the site.

Assessment of Fungal Succession in Decomposing Swine Carcasses (Sus scrofa L.) Using DNA Metabarcoding.

The decomposition of animal bodies is a process defined by specific stages, described by the state of the body and participation of certain guilds of invertebrates and microorganisms. While the participation of invertebrates in decomposing is well-studied and actively used in crime scene investigations, information on bacteria and fungi from the scene is rarely collected or used in the identification of important factors such as estimated time of death. Modern molecular techniques such as DNA metabarcoding allow the identification and quantification of the composition of microbial communities. In this study, we used DNA metabarcoding to monitor fungal succession during the decomposition of juvenile pigs in grasslands of New Jersey, USA. Our findings show that decomposition stages differ in a diversity of fungal communities. In particular, we noted increased fungal species richness in the more advanced stages of decomposition (e.g., bloat and decay stages), with unique fungal taxa becoming active with the progression of decay. Overall, our findings improve knowledge of how fungi contribute to forensically relevant decomposition and could help with the assessment of crime scenes.

Fragment size and diversity of mulches affect their decomposition, nutrient dynamics, and mycorrhizal root colonisation

Plant-based mulch has been proposed as a sustainable way of maintaining soil fertility. However, the role of mulch diversity, quality, and size in decomposition dynamics, and their effect on crop yield, has not been fully explored. We investigated how mulch quality, proxied by the constituent plant species diversity, and residue size drive mulch decomposition, nutrient release, crop nutrition, and yield. A rhizotron experiment was set up with barley as a model crop, with the addition of mulch of two particle sizes (1.5 and 30 cm) and four different plant residue mixes of differing biodiversity (17, 12, 6, and 1 species) in a fully factorial design. Soil nutrient dynamics were measured at advanced decomposition stages, together with residue quality, arbuscular mycorrhizal fungal (AMF) root colonisation, and crop yield. Residue mass loss was significantly affected by its chemical composition. Initial NDF content was more restricted factor in C and N mineralisation than C:N or lignin. Long residues retained significantly higher C and N content, than short residues. Crop yield was not affected by residue type or size. Residue size significantly affected barley growth rate, influencing seed protein content. Soil available K was significantly increased by residues with a higher initial C:N ratio. Short residues resulted in higher soil Zn. Residues of higher diversity resulted inhigher AMF root colonisationof the barley plants. Generally, long residue mulches maintain higher fertilisation capacity at advanced stage of decomposition than short ones, without a deleterious effect on crop yield. Further investigation should evaluate the effect of continuous application of long residue mulches on soil fertility and microbial symbiosis.

Toward Oral Thanatomicrobiology-An Overview of the Forensic Implications of Oral Microflora.

The oral cavity is home to numerous microorganisms including bacteria, fungi, and viruses which together form the oral microflora. It is the second most diverse microbial site in the human body after the gastrointestinal tract. Microbial degradation is a common phenomenon that occurs after death, with the early and advanced stages of decomposition being closely associated with oral microbial activity. This article reviews the current state of knowledge on the role of the oral microflora in postmortem events, and highlights the growing importance of terms such as forensic microbiology and thanatomicrobiome. This article also discusses next-generation sequencing, metagenomic sequencing studies, and RNA sequencing to study the oral thanatomicrobiome and epinecrotic communities in forensic oral genetics. The indigenous microorganisms in the oral cavity are among the first to respond to the process of decomposition. DNA/RNA sequencing is a relatively simple, precise, and cost-effective method to estimate biological diversity during various stages of postmortem decomposition. The field of thanatomicrobiology is rapidly evolving into a key area in forensic research. This article briefly narrates oral microflora and its implications in forensic odontology. The role of microbial activity in postmortem events is gaining importance in forensic research, and further studies are needed to fully understand the potential applications of advanced technology in the study of the oral thanatomicrobiome.

Drone-Based Thermal Imaging in the Detection of Wildlife Carcasses and Disease Management

Because animal carcasses often serve as reservoirs for pathogens, their location and removal are crucial in controlling the spread of diseases. During carcass decomposition, heat is emitted due to microbial activity and the development of maggots. Recent studies have shown that infrared sensors can be used to locate animal carcasses, but little is known about the factors influencing detection success. In this study, we investigated the potential of infrared technology to locate wild boar carcasses, as they play an important role in the spread of African swine fever. Specifically, we tested the effects of environmental and carcass conditions on the detection probability. A drone-based thermal camera was used to collect data during 379 flyovers of 42 wild boar carcasses in different stages of decomposition between September 2020 and July 2021. Generalized mixed-effect models and conditional inference trees were used to identify the environmental and carcass conditions that influenced the detection probability. Our results showed that the thermal camera accurately measured carcass temperature (R2 = 0.75, RMSE = 5.89°C). The probability of finding carcasses was higher in open habitats with air temperatures >3.0°C and thus conducive to maggot development (detection rate ≤80%). A forest canopy openness >29.3% and cloudy conditions or flights at dawn increased the detection rate. Moreover, carcasses infested with large amounts of maggots could be detected even in habitats with a more extensive canopy cover, whereas in dense forests, the detection probability was limited (<25%). Carcasses in an advanced stage of decomposition could still be detected as long as the difference between the carcass temperature and the air temperature was >6.4°C (≤62%). Our study demonstrates the utility of thermal imaging in searching for wild boar carcasses under specific environmental and carcass conditions and thus its use in supporting ground searches.

Post-mortem interval estimation using miRNAs of road traffic accident cases: A forensic molecular approach

In forensic examination accurate estimation of post-mortem interval (PMI) is a challenging task, particularly in the advanced stages of decomposition. The existing methods (algor mortis, livor mortis, rigor mortis, putrefaction etc) used for estimating PMI rely on analyzing the physical, biochemical, and metabolic changes that occur in the corpse after death. While these methods have shown some level of effectiveness in estimating PMI during the early stages of decomposition, accurate estimation becomes increasingly challenging during the later stages of putrefaction when the body undergoes significant changes. Recently, microRNA (miRNA) profiling due to its relatively small size and stability has emerged as a promising tool in several areas of forensics. This study demonstrates the potential of miRNA for PMI estimation in advanced stages of death. In this study, miRNA-195, miRNA-206, and miRNA-378 were selected as target miRNAs and miRNA-1 as reference miRNA. Left ventricle tissue (5 g) of the heart from 20 forensic autopsies of traffic accident victims (18–32 years) were collected and processed. The samples were held at room temperature for eight different time intervals (12, 24, 48, 72, 96, 120, 168 and 196 h), and RNA was extracted from all the samples using Trizol-based RNA isolation protocol, followed by cDNA synthesis and amplification with commercially available specific miRNA probes in Real-Time PCR (RT-PCR), Ct was calculated. The result showed that miRNAs were associated with PMI. Over time, there were substantial changes in the Ct values of all three miRNAs, with significant reductions observed at 196 h compared to 12 h. miRNA-206 demonstrated significant changes at multiple time intervals, while miRNA-1 remained stable for up to 196 h and thus holds caas an endogenous marker. In conclusion, miRNA has the potential to serve as a valuable tool for estimating PMI, especially during the advanced stages of decomposition, when used in conjunction with established techniques. However, further validation of the study is required to obtain more accurate estimates of PMI.

Morphological changes and protein degradation during the decomposition process of pig cadavers placed outdoors or in tents—a pilot study

The delimitation of the postmortem interval (PMI) is of utmost importance in forensic science. It is especially difficult to determine the PMI in advanced decomposition stages and/or when dead bodies are found under uncommon circumstances, such as tents, or other (semi-) enclosed environments. In such cases, especially when insect access is restricted, morphological assessment of body decomposition is one of the remaining approaches for delimitation of the PMI. However, as this method allows only vague statements/indications about the PMI, it is required to develop new and more reliable methods. One of the most important candidates is the biochemical analysis of protein degradation. In this regard, it has been demonstrated that specific skeletal muscle protein degradation patterns characterize certain time points postmortem and thus can be used as markers for PMI estimation. In order to test this method in different micro-environments, a pilot study using ten pig carcasses was conducted in summer in Northern Germany. The cadavers were openly placed outside (freely accessible for insects), as well as enclosed in tents nearby, and left to decompose to investigate decomposition processes over a time course of 10 days. Muscle samples of the M. biceps femoris were collected on a regular basis and processed via SDS-PAGE and degradation patterns of selected proteins identified by Western blotting. In addition, morphological changes of the cadavers during decomposition were assessed using the total body score (TBS). Results showed that postmortem protein degradation patterns are largely consistent between treatment groups (open field versus tents) despite major morphological differences in the decomposition rate. This field study provides evidence that muscle protein degradation is mostly unaffected by different levels of exposure, making it a sufficient candidate for PMI delimitation under various circumstances.

Estimating minimum post-mortem interval in a Nigerian murder case using Chrysomya megacephala (Fabricius, 1794) (Diptera: Caliphoridae): The first use of forensic entomology

Introduction: This paper presents the first application of forensic entomology in a murder investigation in Nigeria involving the remains of a 54-years victim, on January 9th, 2019 in a shaded wooded area in advanced decomposition, with no clear indication of the time of death. Objectives: To estimate the minimum post-mortem interval of a 54-year-old corpse recovered in the advanced decomposition stage using the blowfly Chrysomya megacephala and the Advance-Degree-day (ADD) method. Results: An autopsy report revealed multiple wounds to the forehead including a bullet hole. Dead embalmed dead maggots recovered from the body were identified as C. megacephala, and an accumulated degree-day model was used to estimate the minimum post-mortem interval. The findings revealed that the recovered larvae were still within the third-instar stage and had accumulated thermal energy between 58 hours (= 1.6 days, equivalent to 38.7 ADD) and 102 hours (= 2.8 days, equivalent to 68.0 ADD), suggesting that the body may have been exposed to insect activity between January 1st and 9th January 2019 after expanding the range to cater for some uncertainties. Conclusion: In this Nigerian murder case, forensic entomology used the calliphorid species C. megacephala to estimate the minPMI to be between 2 and 9 days before the body was discovered, which translates to 1st - 9th January 2019 after consideration of some uncertainties and limitations. This confirmed the crucial role that insects play in providing valuable evidence to complement forensic pathological findings in homicides when conventional methods failed. Notwithstanding difficulties with employing insect evidence in forensic investigations in Nigeria, the application of this modern forensic technique has the potential to aid in the resolution of many unsolved murder cases and expedite the delivery of justice. The ability of law enforcement agencies in Nigeria to use the potential of insects in criminal investigations can be improved through collaborations and training with professionals from diverse professions.

First Stranding Event of a Common Minke Whale (Balaenoptera acutorostrata Lacépède, 1804) Reported in the Gulf of Thailand

On 5 September 2022, a dead baleen whale was found stranded at Laem Phak Bia, Phetchaburi, the Gulf of Thailand, Thailand but could not be identified because it was in an advanced stage of decomposition. It was first suspected to be Omura’s whale (Balaenoptera Omurai), as that is a common species in the Gulf of Thailand. However, the cranium morphology was different from B. omurai and more similar to the common minke whale (Balaenoptera acutorostrata) from the North Pacific Ocean, which has never been reported in Thai territorial waters. The mitochondrial DNA control region (D-loop) was then used to identify the species through the Basic Local Alignment Search Tool (BLAST) available at the National Center for Biotechnology Information (NCBI) GenBank, which resulted in a high percent identity, 96.49 to 98.84, with B. acutorostrata. A Bayesian phylogenetic tree was further used to confirm the species, which grouped with B. acutorostrata from the North Pacific Ocean. This study provides evidence of the first stranding event of B. acutorostrata in the Gulf of Thailand. It is new information that extends previous knowledge on the distribution of the common minke whale and raises the need for more active surveys of cetaceans in the South China Sea going forward.

Estimating the intra-puparial period of Hydrotaea spinigera (Stein,1910) (Diptera: Muscidae) with morphological and gene expression changes

Hydrotaea spinigera (Stein, 1910) (Diptera: Muscidae) is a forensically important sarcosaprophagous species widely distributed throughout the Oriental and Australasian regions. At the advanced decomposition stage or the skeletonize stage, the immature stages of H. spinigera, especially the pupae, can still be found in large quantities and could be used as important indicators to estimate the minimum postmortem interval (PMImin). However, there have been no studies on the intra-puparial period of this species. Herein, we studied morphological and differential gene expression changes during the intra-puparial development of H. spinigera, aiming to accurately estimate the intra-puparial age of H. spinigera. The intra-puparial morphological changes of H. spinigera were observed at seven constant temperatures ranging from 16 °C to 34 °C and divided into 12 sub-stages. Structures that could be used to estimate the intra-puparial age, such as compound eyes, mouthparts, antennae, thorax, legs, wings, and abdomen, were observed in detail, and the developmental process of each structure was divided into 5 to 10 stages. The time range of each sub-stage, or when a structure appeared, was recorded. For the gene expression section, the most suitable reference genes were screened by geNorm, NormFinder, BestKeeper, and ΔCt methods. Based on the selected reference genes, real-time quantitative PCR (RT qPCR) was used to detect the expression changes of the white and hsp90 genes with developmental time at 19 °C, 25 °C, and 31 °C. Results showed that the trend of hsp90 gene expression under different temperatures was not consistent, while white genes exhibited regular changes during development, and could thus be used for age estimation of H. spinigera. This study provides an important basis for forensic entomology to use morphological and differential gene expression for estimating the age of H. spinigera during the intra-puparial period. Moreover, the combination of the two methods can produce a more accurate minimum postmortem interval (PMImin) estimate compared to when each method is used separately.

Post-mortem interval of buried homicides in Okuku, Nigeria

BackgroundPost-mortem interval estimation of carcasses buried in shallow graves is a grey area in Nigerian forensic investigations. Most of the investigations and court decisions on the time of death of concealed homicides are based on assumptions in Nigeria. Therefore, this study investigated the post-mortem interval of buried remains in Okuku, Cross River State of Nigeria using porcine models. This study also provided a model account of the pattern and timeline of decomposition of buried remains in Nigeria.ResultsFour stages of decomposition were identified within the study period which includes fresh, bloat, active decay, and advanced decay stages. Features of bloat stage of decomposition include bloating of the animals and release of putrid odour. The active decay stage was characterized by the absence of maggots, bone exposure, and greyish discolouration of the body. The advanced decay stage of decomposition is characterized by adipocere formation, fungi activities, and bone exposure.ConclusionsBuried bodies do not completely skeletonize within 168 days in a typical Nigerian savannah region. Bloat stage started by the 7th day; the active decay stage started by the 14th day. The fresh stage of decay lasted up to 7 days; the bloat stage lasted for 14 days. The active decay stage lasted about 35 days, and the advanced decay stage started at about the 56th day and progressed until the end of the study.