Southern Oman Research Articles

Two new species and a new record of infaunal crabs (Decapoda: Brachyura: Pinnotheridae and Varunidae) from Oman and Saudi Arabia

Recent surveys of shallow subtidal soft-bottom habitats of Oman and the Red Sea coast of Saudi Arabia have uncovered several crabs new to science. Stemming from these efforts, two crab species are herein described as new to science. The first is a new pinnotherid crab, Indopinnixa arabica n. sp., from northern Oman. The other is a new species of varunid crab, Gopkittisak ngankeeae n. sp., from northern, eastern and southern Oman. Additionally, the first known males of another varunid crab, Brankocleistostoma fossulum (Barnard, 1955), are described and illustrated based on material from eastern Oman and southern Saudi Arabia, also representing a new record of the species for the Arabian region.

Late Neoproterozoic alkaline intrusives in Huqf sediments; a new reservoir target in southern Oman

Abstract Recent drilling in Block 56 on the southern Oman coast NE of Salalah has revealed the presence of intrusive rocks in Huqf sediments. The igneous bodies are found as both discrete and composite, decametre scale sills separated by screens of Huqf host rock. Compositionally they form a cogenetic suite of monzonites and syenites that can be related by fractional crystallization to a gabbro–diorite parental magma. Enrichment in alkalis and other large ion lithophile elements points to either an enriched mantle source or magma-crust interaction on ascent. Geochemical profiles match closely those of the latest Neoproterozoic alkaline eruptives now found as exotic volcanic blocks entrained in the salt diapirs of the Ghaba Salt Basin. Limited geochronological data indicate that the Block 56 intrusives are contemporaneous and derived from the same magma source. Porosities in excess of 10% have been recorded in the intrusives; it is a dissolution porosity created by volume loss during the conversion of primary ferromagnesian minerals to biotite and ferroan dolomite. Porosity creation took place during a short lived, fault-controlled Cretaceous hydrothermal event contemporaneous with uplift and alkaline volcanic activity in the Masirah Ophiolite. The intrusives contain a Huqf-sourced oil with light to medium viscosity appearance. Charging is believed to be coming from the cooler and shallower parts of the South Oman Salt Basin to the north and from beneath thick Cenozoic cover in the basin to the south.

The Proterozoic–Cambrian salt detachment zone at Lakhar Kuh, Iran: a seismic-scale analogue for salt stringers, detachment folding and multiphase structural development

Abstract In the Middle East, significant evaporite units formed in the latest Precambrian–Cambrian, Triassic, Jurassic, Cretaceous and Cenozoic. The Precambrian–Cambrian period gave rise to the Ara Salt carbonate stringer plays, southern Oman and the giant Zagros anticline traps (Hormuz Formation). While outcrops of salt diapirs are common, basal detachment exposures are extremely rare. The Lakar Kuh area of Central Iran reveals the Precambrian–Cambrian basal salt detachment, on satellite images, in natural cross-section view through the entire Phanerozoic sedimentary section east of Ravar. This view illustrates how older diapiric structures (pillows and normal faults) were the focus of later contractional folds, particularly in the Jurassic and Cenozoic. The salt detachment zone contains many floating blocks (stringers) of clastic, carbonate and igneous rocks. Some blocks were stoped from the overlying beds, while most were layers originally interbedded with the evaporites. Block size, distribution and orientation is highly variable, and folding is infrequent. Lakar Kuh encompasses several key themes generally pertinent to structural geology and salt system research: the presence of sedimentary stringers within evaporites, multiple detachment levels within a thick (>5 km) stratigraphic section, detachment folding, multiphase salt activity, reactivation of older structures by newer ones and multi-stage development of salt bodies.

Sequence stratigraphic framework and distribution of potential reservoirs: Early Cretaceous Qishn Formation, Dhofar, Southern Oman

Sequence stratigraphic framework and distribution of potential reservoirs: Early Cretaceous Qishn Formation, Dhofar, Southern Oman

Review of the Newly Established amictus-Subgroup of the Genus Leptocoris (Hemiptera: Heteroptera: Rhopalidae), with the Description of a New Species from the Arabian Peninsula

Leptocoris arabicus new species (Hemiptera: Heteroptera: Rhopalidae: Serinethinae) is described based on 55 specimens of both sexes collected in various localities of southern Oman and southeastern Yemen; a hypothesis is proposed as to its host plant. The new species is close to Leptocoris amictus Germar, 1838 and to Leptocoris ruber Göllner-Scheiding, 1980, new status, due to the presence of a produced horned process along the posterior ventral margin of the genital capsule. It is distinguished from both by differences in colour pattern and morphology. An informal L. amictus species-subgroup is proposed to accommodate these three species within the Leptocoris hexophthalmus species-group sensu Göllner-Scheiding (1980). The following new faunistic records are also provided: L. amictus from Ethiopia, Mozambique and Zambia; L. ruber from Central African Republic. The occurrence of L. chevreuxi (Noualhier, 1893) in Oman is confirmed. The list of all available species-group names assigned to Leptocoris Hahn, 1833 (gender masculine) and their synonyms is compiled and the gender agreement is corrected in the species names when appropriate. The nomenclatural problem concerning Leptocoris living on Marshall Islands discovered by Kerzhner (2003) is discussed and the following corrections are provided: Leptocoris rufus rufus Hahn, 1833, new status = Leptocoris lariversi Usinger, 1952, new synonymy, and Leptocoris rufus isolatus (Distant, 1914) new status.

Closure of Khor Al Balid and Khor Rori harbours/estuaries with coastal uplift and aridity in the 12th – 15th c. CE and evidence for an extreme overwash event in the 18th – 19th c. CE: Implications for ancient port sites in southern Oman

Ancient maritime trading ports along the southern coast of Oman have been the target of archaeological excavations for several decades. Though historical chronologies are well-researched, information from a paleoenvironmental perspective is lacking and can provide a more complete understanding of site development. This study investigates the timing of coastal sand barrier accumulation in the natural harbours at Khor Al Balid and Khor Rori, which had considerable effects on the populations at the ancient cities of al–Balīd and Sumhuram, respectively. Six cores from Khor Al Balid and four cores from Khor Rori were analyzed using sedimentological, microfossil (foraminifera and testate amoebae), geochemical (μXRF), and radiocarbon dating methods. Marine proxies (e.g., Amphistegina spp., C. pseudolobatulus, E. limbatum, Sr, Ca/Si) and lagoon proxies (e.g., T. macrescens, T. inflata, C. constricta and C. aculeata, Ti/Ca, Fe/Ca) were used to identify Marine Sand, Brackish Lagoon/Marsh, and Freshwater facies. Results indicate that the eastern arm of Khor Al Balid closed off from the sea around the 12th century CE and that the western arm closed around the 15th century CE. Siltation of harbours and the formation of sand barriers may have contributed towards site abandonment. Previous archaeological findings suggest that al-Balīd was able to continue with maritime trade activities along the southern seaside edge of the city for several centuries after siltation of Khor Al Balid, possibly with the help of dredging. An extreme overwash event was recorded in almost all cores across both sampling sites, suggesting that a very large cyclone or a tsunami hit the southern Oman coast sometime around the 18th–19th century CE. This event, as well as continuous coastal sand accumulation, may have contributed to the decline and abandonment of Khor Al Balid and highlights the impacts that large storm/wave events have on archaeological site preservation.

SAGD Trial in Omani Heavy Oil Field Overcomes Suboptimal Conditions

_ This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 215943, “Short Spacing, Lower Viscosity, and Suboptimal Operating Conditions SAGD Trial in Mukhaizna Heavy Oil Field,” by Buthaina S. Al Yahmadi, Rawaa M. Al Aamri, and Walaa S. Al Suqri, Oxy, et al. The paper has not been peer reviewed. _ Mukhaizna is a heavy oil field in southern Oman. It is a multistacked reservoir that has been producing under steamflood since 2007. The main sandstone reservoirs were developed using horizontal producers in each target zone supported by vertical injectors. Although most of the patterns are thermally mature, a few areas still are awaiting steamflood response. To mature these areas, a steam-assisted gravity drainage (SAGD) pilot was evaluated, customized, and implemented using existing patterns and well configurations. Mukhaizna Field The Mukhaizna heavy oil field contains viscous, low-gravity (14–18 °API) crude oil in the shallow Permian-age sands of the Gharif formation. Porosity is very good (25–35%), as is permeability (1,000–10,000 md). The Gharif formation consists of upper, middle, and lower reservoirs. Different injector and producer configurations were evaluated to ensure good production. Because a shale barrier clearly was present in the Gharif formation in most of the area but absent elsewhere, the development of this formation was affected. After evaluation of various pattern-configuration options, a development plan was based on three vertical injectors and three horizontal producers per pattern. Thermal development of the field with steam injection began in July 2007. Steamflood maturity has been inconsistent across the field. Various methods of optimizing steam-injection volumes or steam reshuffling in the offset injectors in some patterns were attempted in order to accelerate thermal maturity, but some horizontal producers were still cold with low inflow. To solve this, a pilot-project area with two stacked horizontal producers was evaluated for SAGD potential. These two producers targeted the same zone, Upper Gharif 2A, in one of the best reservoirs in the field. This area was supported by a horizontal injector that had strong communication with the lower producer, but because of misalignment between the horizontal injector and the upper producer, the upper producer was cold, with its progressive cavity pump at pumpoff condition. To evaluate this SAGD trial and predict performance, two analogs were reviewed to compare reservoir properties and parameters. The first analog, Jackfish1, is considered a successful SAGD project, exceeding 90% of its nameplate capacity since first steam. The second analog is Xinjiang oil field, which was not a successful SAGD project, with a steam/oil ratio (SOR) reaching 4.3. This SAGD trial aimed to enhance the oil production of cold patterns with two stacked wells while gaining an understanding of the potential challenges and opportunities of applying SAGD in the existing well configurations at Mukhaizna. The upper horizontal well was converted to a steam injector with an insulated tubing completion. The nearby horizontal injector was kept at the same injection rate to avoid any changes in operating conditions around the SAGD trial.

The tectonic setting of the late Ediacaran eastern Arabian basement (ca. 550 Ma): New geochronological and geochemical constraints from the basements of Oman and the United Arab Emirates

The thick Phanerozoic sedimentary cover lying above the Arabian Platform conceals extensive basement between the western Neoproterozoic domains of the Arabian Nubian Shield (ANS) and of the eastern Omani basement. The Neoproterozoic rocks entrained within salt domes that crop out within the United Arab Emirates (UAE) and Qatar are the only direct samples that allow us to investigate the tectonic history of the concealed Arabian basement domains before c. 550 Ma. This study focuses on the U-Pb geochronological and REE geochemical analysis of detrital zircon, apatite, titanite and rutile grains from the Zirku turbidites brought to the surface by halokinetic movements offshore UAE. These data are compared with new U-Pb and REE data from detrital heavy minerals of three metasedimentary members of the Omani Neoproterozoic Hatat Formation collected in the Saih Hatat window. The Omani metasedimentary units yield detrital titanite, zircon and apatite U–Pb ages that span from c. 2500 to 690 Ma, with an age maxima at c. 850 Ma, while the UAE unit yield ages from c. 2550 to 550 Ma with major age peaks at c. 1000, 820, 650 Ma. The analysis of the Omani stratigraphic sequence in the Saih Hatat window revealed that the rocks of the Neoproterozoic Hatat Formation yield similar age distributions of the Abu Mahara Group (lower Huqf Supergroup, exposed in central and southern Oman), and that the REE geochemical composition of the Hatat detrital apatite grains shares akin REE signature with the c. 550 detrital apatite of the Zirku Formation, with both being sourced from volcanic-arcs. These new geochronological and geochemical data, together with recent geophysical evidences, suggest that the basement of the UAE is originally part of the Oman tectonic domain and evolved as part of a volcanic-arc in an active margin at c. 550 Ma, which we interpret as part of the retro-arc of the Cadomian collision in between the Arabian and the Cadomian Taurides, Iran and Afghanistan terranes.

Goatfishes (Teleostei: Mullidae) of the Socotra Archipelago: diversity and distributional biogeography, with a new record of Parupeneus heptacantha

The diversity of goatfishes from the Socotra Archipelago is documented for the first time. The distributional biogeography of the family in the Arabian region is analyzed and thoroughly discussed in the context of the western Indian Ocean. Twelve species of two genera, Mulloidichthys and Parupeneus, are positively recorded, including a new record for Parupeneus heptacantha and a visual recording of Upeneus heemstra, pending further documentation. The Socotra Archipelago thus hosts 13 of the 31 species found in Arabia. This degree of species richness is comparable to other Arabian ecoregions. With only one species, Upeneus species richness stands out as very low. Biogeographically, three main Arabian units are identified: a "Red Sea unit", a "Gulf unit", and a "Socotra unit". The former two units are strongly characterized by endemics, notably within Upeneus, while there are no species endemic to the latter. The "Socotra unit", comprised of the Socotra Archipelago, eastern Gulf of Aden, and southern Oman, resembles more strongly all sites of the western Indian Ocean than the Arabian sites. The "Gulf unit" is the most distant to all other sites. These units do not cluster to a discrete "pan-Arabian" region within the wider western Indian Ocean. The Mullidae thus strongly contrast overall biogeographic patterns of coastal fishes and reef-building corals, which cumulatively suggest that Arabia forms a discrete biogeographic unit within the Indian Ocean. The study serves further analyses of the contrasting biogeographies of major coastal fish families in Arabia, with a focus on the role of the southern Arabian upwelling areas.

Parrotfishes (Teleostei: Labridae: Scarini) of the Socotra Archipelago: Diversity and distributional biogeography, including a range extension of Scarus zufar Randall & Hoover, 1995.

An updated account of the diversity of parrotfishes from the Socotra Archipelago is provided. Fourteen species are positively recorded based on underwater observations, photography and collections, including confirmations of three species which were previously only tentatively recorded: Scarus falcipinnis(Playfair, 1868), Scarus scaber Valenciennes, 1840 and Scarus tricolorBleeker, 1847. The distribution of Scarus zufar Randall & Hoover, 1995, previously known only from coastal waters of southern Oman, Pakistan and Bangladesh, is extended to the Archipelago, with Abd al-Kuri Island representing the westernmost edge of its known range. Visual records of three additional species are yet to be documented. With 1417species the Archipelago approximates the modal richness range of 1518 species for Arabian ecoregions. A species account, accompanied by photographs, provides distinctive characters, distribution details in the Arabian region, and general remarks for each species. The distributional biogeography of the family pertinent to the Socotra Archipelago and the Arabian region is analysed in the context of the Western Indian Ocean. Three main Arabian units are identified: A Red Sea unit spans the combined Red Sea ecoregions and the western Gulf of Aden; a Socotra unit covers south-eastern Arabia including the Archipelago, the eastern Gulf of Aden and southern Oman; and a Gulf unit combines the Arabian/Persian Gulf, the Gulf of Oman, and putatively central Oman. These units form a discrete pan-Arabian cluster within the wider Western Indian Ocean. The Socotra unit resembles more strongly the Gulf unit than the Red Sea unit. Parrotfishes thus contrast overall distributional patterns of reef fishes in Arabia.

A New Species of the Shrimp Genus Salmoneus Holthuis, 1955 (Malacostraca: Decapoda: Alpheidae) from the Exposed Shores of Eastern and Southern Oman

Salmoneus sultanus sp. nov. is described based on several specimens collected on the exposed shores of Masirah Island and Dhofar, Oman, a region characterised by seasonal upwellings cooling water temperature to less than 23 °C. The new species is compared with the morphologically most similar congeners present in the north-western Indian Ocean, e.g., S. latirostris (Coutière, 1897), S. cristatus (Coutière, 1897), S. serratidigitus (Coutière, 1897), and S. chadwickae Ďuriš and Horká, 2016; the latter species is recorded for the first time from Oman. The conspicuous colour pattern of S. sultanus sp. nov. appears to be diagnostic, differing greatly from that of S. latirostris, S. cristatus, S. serratidigitus, and S. chadwickae.

Noble gases in groundwater reflect wet-season temperature in an arid, monsoonal, and mountainous environment

Comparing directly measured soil temperatures with noble gas recharge temperatures (NGTs) inferred from noble gas concentrations indicates that the infiltrating soil water equilibrates with soil air near the soil surface during the rainy season. Therefore, NGTs of groundwater recently recharged by the Indian Summer Monsoon (ISM) in the Dhofar Mountains in southern Oman reflect the soil temperatures of the 3-month period and do not represent an annual mean. This finding highlights the need to account for seasonality when interpreting NGT data in regions with pronounced dry and wet seasons.We extend the observations from the southern flank of the Dhofar Mountains to three wells situated on the northern flank of the Dhofar Mountains. Two of these wells yield water of Holocene age that was recharged by the monsoon, their NGT signals are therefore classified as seasonal. The NGT calculated from a third well for recharge conditions during the Last Glacial Maximum (LGM), when the ISM was absent, is approximately 3 °C lower than that of the two Holocene wells. The lower LGM noble gas temperature corresponds well with the lower annual Sea Surface Temperature (SST) in the nearby Arabian Sea.NGTs from published studies from northern Oman are 1–3 °C higher when compared with our data of the same period in the southern Oman. We explain this regional difference of reconstructed temperatures for the LGM and Holocene groundwater with a more continental climatic influence on the infiltration conditions further to the north. The published NGTs from northern Oman show a large temperature difference between the late Holocene and the LGM. In view of our finding of seasonal NGT signals under monsoonal climate, part of this difference may reflect a change in the precipitation regime rather than in air temperature.

Epenthesis and vowel intrusion in Central Dhofari Mehri

Abstract The paper discusses epenthesis and vowel intrusion in the Central Dhofari variety of Mehri, one of six endangered Modern South Arabian languages indigenous to southern Arabia. Mehri is spoken by members of the Mahrah tribe in southern Oman, eastern Yemen, parts of southern and eastern Saudi Arabia and in communities in parts of the Gulf and East Africa. The estimated number of Mehri speakers is between 100,000–180,000. Following Hall (2006), this study distinguishes between two types of inserted vowels: epenthetic vowels, which repair illicit syllable structures, and intrusive vowels, which transition between consonants. The paper examines how the properties of epenthetic and intrusive vowels as proposed by Hall relate to Mehri.

Holocene climate change in southern Oman deciphered by speleothem records and climate model simulations

Qunf Cave oxygen isotope (δ18Oc) record from southern Oman is one of the most significant of few Holocene Indian summer monsoon cave records. However, the interpretation of the Qunf δ18Oc remains in dispute. Here we provide a multi-proxy record from Qunf Cave and climate model simulations to reconstruct the Holocene local and regional hydroclimate changes. The results indicate that besides the Indian summer monsoon, the North African summer monsoon also contributes water vapor to southern Oman during the early to middle Holocene. In principle, Qunf δ18Oc values reflect integrated oxygen-isotope fractionations over a broad moisture transport swath from moisture sources to the cave site, rather than local precipitation amount alone, and thus the Qunf δ18Oc record characterizes primary changes in the Afro-Asian monsoon regime across the Holocene. In contrast, local climate proxies appear to suggest an overall slightly increased or unchanged wetness over the Holocene at the cave site.

Chemical composition of monsoon bulk precipitation in the Salalah area, Oman

Precipitation chemistry data provide important information for environmental studies on large-scale element cycling and anthropogenic impacts on our atmosphere, but also for hydrochemical models and groundwater recharge estimations via the Chloride Mass Balance method. Such recharge data play a crucial role in groundwater management, particularly in (semi-)arid areas. Unfortunately, precipitation analyses are often scarce in such regions. This also applies to the Arabian Peninsula, including southern Oman. To overcome this lack of rain chemistry data, we developed a strategy for automatic weekly bulk precipitation sampling, using recently designed automatic rainwater samplers. The integral samples were gathered along an elevation gradient from the Salalah coast to the Dhofar mountains during the Indian Ocean Monsoon seasons 2017 and 2018.Our major ion analyses of the rainwater samples revealed considerable temporal and spatial heterogeneity, in terms of ion proportions and absolute concentrations. Samples from the coast were relatively salty (EC mostly >3000 μS cm−1) and rich in Na+ and Cl−, reflecting small rain amounts and a sea spray effect. Further inland, solute concentrations were lower, partly due to more precipitation, and ions such as Ca2+ and SO42− gained importance, probably due to calcite and gypsum dust. This pattern reflects the interplay between solute availability (influenced by regional geology, wind direction at different altitudes, and wind speed) and precipitation amounts. Cl−/Br− ratios were fairly uniform and scattered around the seawater value. Combining ion concentrations and rain amounts yielded bulk depositions that showed an erratic pattern along the elevation gradient, i.e., depositions did not decrease steadily in inland direction, as one may assume. This suggests that the occasionally reported approach of collecting a few opportunistic grab samples at a single site is unlikely to yield data that are representative for a larger coastal study area.

Optimization of green hydrogen production in hydroelectric-photovoltaic grid connected power station

The escalating trend of using hydro and solar resources to generate electricity and providing green hydrogen for the transportation sector is considered as a most optimal pathway to reducing the greenhouse gas emission. As a contribution, this study focuses on optimizing the production of green hydrogen in a combined hydroelectric-photovoltaic power station located in southern Oman. The study employed a simulated model to perform techno-economic analysis and optimize the components of the hybrid power station. The model aims to optimize the components of hydroelectric photovoltaic hybrid power station connected to the power grid. The fundamental parameters to perform this analysis are the average stream flow and solar radiation. This study is depicting the production of hydrogen from a power grid as well as its utilization in conversion to green hydrogen. The economic analysis of the project depends mainly on the cost of hydro turbines, power converters, PV panels, electrolyzers and hydrogen tanks. After the overall analysis, the researchers have concluded that the net profit is playing an imperative role in optimizing the levelized cost of green hydrogen to be €2.25/kg. This analysis is providing the opportunity to the researchers to do techno-economic analysis of the hydrogen production and to utilize the produced hydrogen to facilitate green transportation thereby reducing the greenhouse gas emission.

Prehistoric Settlement Patterns in Southern Oman from the Lower Palaeolithic to the Neolithic

Prehistoric Settlement Patterns in Southern Oman from the Lower Palaeolithic to the Neolithic

Dynamic Change in Normalised Vegetation Index (NDVI) from 2015 to 2021 in Dhofar, Southern Oman in Response to the Climate Change

Climate change poses a major threat to vegetation and land cover worldwide. The loss of vegetation as a result of climate change can alter the functions and structure of the environment and its ecological systems. In the first part of this study, Sentinel-2 data, normalised different vegetation index (NDVI), and multiple regression methods were used to examine the impacts of the climatic factors of humidity, rainfall, and air temperature on vegetation dynamics from 2015 to 2021 in Dhofar, Southern Oman. In the second part of this study, random forest regression was employed to model the relationships between the NDVI and temperature, humidity, rainfall, soil map, geology map, topographic wetness index, curvature, elevation, slope, aspect, distance to buildings, and distance to roads. The multiple regression values revealed significant associations between the spatial distributions of the NDVI and the abovementioned climatic factors. The findings also indicated an increase of 1 °C in air temperature fluctuations between 2018 and 2021 over all five sites, with a strong tendency over Qairoon Hairiti Mountain. The rainfall records clearly indicated an increasing tendency from 2018 to 2020 due to the impact of frequent cyclones. Therefore, the results revealed a significant increase of 0.01 in the vegetation cover trend in 2018, 2019, and 2020 along the Sadah Mountain range and the eastern part of the Jabal Qara Mountains under the areas directly impacted by the cyclone, whereas there was a decrease along the western mountain range consisting of Jabal Qara and Jabal Qamar Mountains due to the impact of warm, dry air. The results revealed that NDVI values were sensitive to heavy rainfall over Jabal Samhan Mountain. The 12 variables that influenced NDVI levels had different levels of importance. Soil types, elevation, slope, rainfall, curvature, humidity, and temperature had the highest importance, while topographic wetness index, distance to urban area, aspect, distance to roads, and geology map had the lowest. The findings provide a significant foundation for Oman’s planning and management of regional vegetation, water conservation, and animal husbandry.

Seroprevalence and Risk Factors of Brucellosis in Ruminants in Dhofar Province in Southern Oman.

The aim of the present work was to raise awareness of Brucella infection and emphasize the use of serological tests for screening and confirmation of the presence of the infection in different localities in the Dhofar region in the Sultanate of Oman. A seroprevalence of Brucella infection in naturally infected livestock was undertaken in 50 farms (a total of 434 sera, 207 goats, 84 sheep, 54 cattle, and 89 camels) from different wilayat of the Dhofar region in the southern part of Oman. Rose Bengal (RBT), complement fixation (CFT), and indirect enzyme-linked immunosorbent assay (I-ELISA) tests were used to determine the presence of Brucella antibodies. Statistical analysis (Pearson chi-square, binary logistic regression, and univariate logistic regression) was used to investigate the significance between the prevalence and the categorical risk factors individually, with two or more levels (animal species, animal condition, and or location). Our results show that the overall seroprevalence based on CFT, RBT, and I-ELISA was 3% (13/424, CI: 1.8-5.1%), 4.8% (21/434, CI: 3.1-7.3%), and 8% (35/434, CI: 5.8-10.9%), respectively. The highest seroprevalence was reported in goats (13% (27/207)) and animals from East Jabal (13% (21/161)), whereas the lowest was recorded in camels (3.4% (3/89)) and animals from deserts (1.4% (1/69)). Parameters such as the positive predictive value (PPV) and the negative predictive value (NPV) showed that the sensitivity of I-ELISA and CFT based on the RBT test was 61.9% and 57.1%, respectively, whereas the specificity of I-ELISA (94.6%) was less than that of CFT (97.33%). We concluded that three tests are confirmatory for the presence of Brucella infection.

First Records of Black Widow Spider Latrodectus Walckenaer (Araneae: Theridiidae) in Oman

The present communication deals with a faunistic study on two species of Latrodectus Walckenaer with medically important issues from Oman. Several specimens of Latrodectus have been collected at various localities in Sultanate of Oman. This study records two species of Latrodectus from Oman, of which Latrodectus cinctus Blackwall only from northern Oman and Latrodectus geometricus C.L. Koch from both northern and southern Oman.