Genus Panulirus Research Articles

The mitochondrial genomes of the reef-dwelling spiny lobsters Panulirus echinatus and Panulirus interruptus with insights into the phylogeny and adaptive evolution of protein-coding genes in the Achelata

Temperature and oxygen levels drive the evolution of morphological, behavioral, and physiological traits in marine invertebrates, including crustaceans. Environmental conditions are also expected to prompt the adaptive evolution of mitochondrial protein-coding genes (PCGs), which are vital for energy production via the oxidative phosphorylation pathway. We formally tested for adaptive evolution in mitochondrial protein-coding genes in representatives of the decapod infraorder Achelata, including two spiny lobsters, Panulirus echinatus and P. interruptus, for which we sequenced complete mitochondrial genomes (15,644 and 15,659 bp long, respectively). A phylomitogenomic analysis supported the monophyly of the genus Panulirus, the families Palinuridae and Scyllaridae, and the infraorder Achelata. Over the strong negative selection background observed for mitochondrial PCGs in the Achelata, signatures of positive selective pressure were detected within PCGs in equatorial Panulirus spp. and deepwater Scyllaridae. In Panulirus spp. inhabiting equatorial latitudes with consistently high temperatures, the Datamonkey analysis RELAX suggested intensified purifying selection strength in 9 of the 13 PCGs and relaxation in purifying selection strength in atp6, while aBSREL, BUSTED, and MEME recovered signatures of positive selection on PCGs within Complex I, III, and IV PCGs. Likewise, in Scyllaridae species inhabiting depths with low-oxygen levels, RELAX indicated relaxed selection strength in 6 of the 13 PCGs, while aBSREL, BUSTED, and MEME recovered signatures of positive selection on PCGs within Complexes I, III, IV, and V. The newly assembled mitochondrial genomes of P. echinatus and P. interruptus represent new genomic resources to aid with the conservation and management of lobsters targeted by major fisheries and contribute to our understanding of how environmental conditions drive adaptive evolution in spiny and slipper lobster mitochondrial PCGs.

Genomics resources for the Rapa Nui (Eastern Island) spiny lobster Panulirus pascuensis (Crustacea: Decapoda: Achelata)

BackgroundThe Easter Island spiny lobster Panulirus pascuensis (Reed, 1954) or ‘Ura’ in the Rapa Nui language, is a little known species native to the south eastern Pacific Ocean, distributed along the coasts of Easter Island, Pitcairn Island, and the Salas y Gómez Ridge. In Easter Island, P. pascuensis is the target of a small and profitable and probably overexploited fishery. In this study, we profited from a series of bioinformatic analyses to mine biological insight from low-pass short-read next generation sequencing datasets; we have estimated genome size and ploidy in P. pascuensis using a k-mer strategy, discovered, annotated, and quantified mobile elements in the nuclear genome, assembled the 45S rRNA nuclear DNA cassette and mitochondrial chromosome, and explored the phylogenetic position of P. pascuensis within the genus Panulirus using the signal retrieved from translated mitochondrial protein coding genes.ResultsK-mer analyses predicted P. pascuensis to be diploid with a haploid genome size ranging between 2.75 Gbp (with k-mer = 51) and 3.39 Gbp (with k-mer = 18). In P. pascuensis, repetitive elements comprise at least a half and a maximum of three fourths of the nuclear genome. Almost a third (64.94%) of the repetitive elements present in the studied nuclear genome were not assigned to any known family of transposable elements. Taking into consideration only annotated repetitive elements, the most abundant were classified as Long Interspersed Nuclear Elements (22.81%). Less common repetitive elements included Long Terminal Repeats (2.88%), Satellite DNA (2.66%), and DNA transposons (2.45%), among a few others. The 45S rRNA DNA cassette of P. pascuensis was partially assembled into two contigs. One contig, 2,226 bp long, encoded a partially assembled 5′ ETS the entire ssrDNA (1,861 bp), and a partial ITS1. A second contig, 6,714 bp long, encoded a partially assembled ITS1, the entire 5.8S rDNA (158 bp), the entire ITS2, the entire lsrDNA (4,938 bp), and a partial 3′ ETS (549 bp). The mitochondrial genome of P. pascuensis was 15,613 bp long and contained 13 protein-coding genes (PCGs), 22 transfer RNA (tRNA) genes, and two ribosomal RNA genes (12S ribosomal RNA [rrnS] and 16S ribosomal RNA [rrnL]). A phylomitogenomic analysis based on PCGs retrieved Panulirus pascuensis as sister to a fully supported clade comprising P. cygnus and P. longipes.ConclusionWe expect that the information generated in this study will guide the assembly of a chromosome-level nuclear genome for P. pascuensis in the near future. The newly assembled 45S rRNA nuclear DNA cassette and mitochondrial chromosome can support bioprospecting and biomonitoring of P. pascuensis using environmental DNA. The same elements can help to survey the public market place and detect mislabelling of this and other spiny lobsters. Overall, the genomic resources generated in this study will aid in supporting fisheries management and conservation strategies in this iconic spiny lobster that is likely experiencing overexploitation.

Characterization of Six Lobster Species of Genus Panulirus (Decapoda, Palinuridae) from Aceh Waters, Indonesia Based on Morphometric Analysis

Characterization of Six Lobster Species of Genus Panulirus (Decapoda, Palinuridae) from Aceh Waters, Indonesia Based on Morphometric Analysis

Species Composition, Relative Abundance, Distribution, and Size Structure of Spiny Lobsters (Panulirus spp.) in Eastern Visayas, Philippines

Spiny lobsters are an important resource of the artisanal fishery in Eastern Visayas, Philippines. It has long been harvested and contributes to the region's local economy. Despite being a high-value species, the spiny lobster resource has not been monitored and regulated for decades. This study aimed to assess the spiny lobsters in Eastern Visayas and provide recent information to support local resource management. Spiny lobsters were assessed from 2018 to 2019 in four major sampling areas in Eastern Visayas: (1) Guiuan and (2) San Policarpo in Eastern Samar province, (3) San Jose in Northern Samar, and (4) Silago-Hinunangan in Southern Leyte. Species composition, relative abundance, geographical and seasonality distribution, and size structure of spiny lobster resource in the region were described. Six species and subspecies of the genus Panulirus were observed in the catch landings: P. penicillatus (65%), P. ornatus (18%), P. versicolor (2.8%), P. femoristriga (5.3%), P. longipes longipes (6.1%), and P. longipes bispinosus (1.7%). Incidental catches (1.3%) of the ambiguous forms of P. longipes were also observed. P. penicillatus were more prevalent in areas exposed to the Pacific, such as Guiuan and San Policarpo, while adult P. ornatus were chiefly harvested in Northern Samar and Southern Leyte. The other lobster species were either occasional or rare in some areas. Calmer waters and good weather during dry months in Eastern Visayas allow fishers to sail and gather lobsters. The surge in the abundance of P. ornatus and P. penicillatus from July to December was also affected by market demand. Panulirus femoristriga, P. versicolor, and P. longipes subspecies generally peaked from April to June in Eastern Samar and July to September in Northern Samar and Southern Leyte areas. These species would decline in abundance towards the end of the year. The general size structure of spiny lobster catches in Eastern Visayas revealed extreme harvesting of juveniles and sub-adults (< 77.5 mm CL), except for P. ornatus. The fishery could be on the verge of growth overfishing since 50-90% of the catch have CL below their size at first maturity. Panulirus ornatus is targeted at larger sizes (96–107 mm CL) and as a live catch due to its high value and marketability. Raising awareness of the species, reinforcing existing regulations on minimum size limits, and prohibiting the use of compressor diving as a hazardous collection method should be prioritized by fishery managers to protect both the spiny lobster resource and the gatherers in Eastern Visayas.

A comprehensive description of the exoskeleton of six Lobster species (Genus Panulirus) in Aceh Province, Indonesia

Lobster (Panulirus spp.) is a leading commodity on a local and export scale in Aceh Province, Indonesia, where the population has experienced a significant decline in recent years. This study describes the exoskeleton morphology of six lobster species distributed in Aceh Province, Indonesia. The research was carried out in 2022 with stages covering sample preparation, sample shooting, and morphological analysis. The results of the study showed that there were six lobster species in Aceh including Panulirus penicillatus, P. homarus, P. longispes, P. ornatus, P. versicolor, and P. polyphagus. The anatomy of the lobster exoskeleton of six species of P. penicillatus, P. homarus, P. longispes, P. ornatus, P. versicolor and P. phloyphagus has marked differences, where each part of the cephalothorax (cervical sulcus, sternum, epistome, maxillaped, pereiopod), Abdominal (segment, pleura, pleopod) and caudal (telson, uropod, and protopod) have different shapes. In addition, differences were also found in the color and presence of spines on the dorsal body.

The diversity of the Genus Panulirus trafficked through the Fish Quarantine Station Controlling the Quality and Safety of Fishery Products, Aceh Province

The genus Panulirus is one of the important fishery commodities for Aceh Province. In the context of the sustainability of these resources, it is necessary to apply regulations properly. The purpose of the apprenticeship activity is to determine the type, number and origin of the lobster catching area that is trafficked through the Fish Quarantine Station for Quality Control and Safety of Fishery Products in Aceh. The activity is carried out from February to April 2022. The method used is by observing activities, and collecting data on the types of lobsters that are trafficked. There are 6 types of lobster that are trafficked at the Fish Quarantine Station for Quality Control and Safety of Fishery Products in Aceh, including; Panulirus homarus, Panulirus ornatus, Panulirus penicillatus, Panulirus polyphagus, Panulirus longipes and Panulirus versicolor. Every month the quarantine stations carry out inspections before shipping an average of 1929 individuals per month. The type of Panulirus versicolor is the type with the highest percentage (34%) sent through. The origin of lobster catching consists of 8 areas, namely Banyak Island (Aceh Singkil), Simeulue Island, Labuan Haji (South Aceh), Meulaboh (West Aceh), Calang and Lamno (Aceh Jaya), Banda Aceh and Sabang Island.

CONFIRMAÇÃO DA OCORRÊNCIA DA Panulirus laevicauda (LATREILLE, 1817) NO GRANDE SISTEMA DE RECIFES DA AMAZÔNIA, AMAPÁ, BRASIL

The spiny lobsters of the genus Panulirus White, 1847 are widely exploited and commercialized in northern and northeastern Brazilian coastal regions. One of the species, the smoothtail spiny lobster Panulirus laevicauda (Latreille, 1817) had its distribution demarcated from Amapá to Santa Catarina State, but it was dubiously recorded in northern coast from industrial fishing samples, without collected material or photographs for taxonomic identification. Based on this, we report the occurrence of P. laevicauda in the northern region of Brazil (Amapá State) through material collected. The male specimen was collected on November 07th, 2022, at the depth of 84.5m, during commercial fishery operations of the red snapper Lutjanus purpureus (Poey, 1866), at the area of the Great Amazon Reef System (GARS) (04°45’29.849”N; 050°39’41.567”W). The current record confirms the occurrence of the species in Northern Brazil and it is the first report for the GARS.

DNA barcoding and morphological identification of spiny lobsters in South Korean waters: a new record of Panulirus longipes and Panulirus homarus homarus.

To date, 19 species of spiny lobsters from the genus Panulirus have been discovered, of which only P. japonicus, P. penicilatus, P. stimpsoni, and P. versicolor have been documented in South Korean waters. In this study, we aimed to identify and update the current list of spiny lobster species that inhabit South Korean waters based on the morphological features and the phylogenetic profile of cytochrome oxidase I (COI) of mitochondrial DNA (mtDNA). Spiny lobsters were collected from the southern and eastern coasts of Jeju Island, South Korea. Phylogenetic analyses were performed using neighbor-joining (NJ), maximum likelihood (ML), and Bayesian inference (BI) methods. The ML tree was used to determine the spiny lobster lineages, thereby clustering the 17 specimens collected in this study into clades A, B, C, and D, which were reciprocally monophyletic with P. japonicus, P. homarus homarus, P. longipes, and P. stimpsoni, respectively. These clades were also supported by morphological examinations. Interestingly, morphological variations, including the connected pleural and transverse groove at the third abdominal somite, were observed in four specimens that were genetically confirmed as P. japonicus. This finding is novel within the P. japonicus taxonomical reports. Additionally, this study updates the documentation of spiny lobsters inhabiting South Korean waters as P. longipes and P. homarus homarus were recorded for the first time in this region.

A Comprehensive Description of the Exoskeleton of Six Lobster Species (Genus Panulirus) in Aceh Province, Indonesia

A Comprehensive Description of the Exoskeleton of Six Lobster Species (Genus Panulirus) in Aceh Province, Indonesia

Detection of heteroplasmy and nuclear mitochondrial pseudogenes in the Japanese spiny lobster Panulirus japonicus

Partial mtDNA cytochrome oxidase subunit I (COI) fragments and near entire stretch of 12S rDNA (12S) and control region (Dloop) of the Japanese spiny lobster (Panulirus japonicus) (n = 3) were amplified by PCR and used for direct nucleotide sequencing and for clone library-based nucleotide sequence analysis. Nucleotide sequences of a total of 75 clones in COI, 77 in 12S and 92 in Dloop were determined. Haplotypes of the clones matched with those obtained by direct sequencing were determined to be genuine mtDNA sequence of the individual. Phylogenetic analysis revealed several distinct groups of haplotypes in all three regions. Genuine mtDNA sequences were observed to form a group with their closely related variables, and most of these variables may be due to amplification error but a few to be heteroplasmy. Haplotypes determined as nuclear mitochondrial pseudogenes (NUMTs) formed distinct groups. Nucleotide sequence divergence (K2P distance) between genuine haplotypes and NUMTs were substantial (7.169–23.880% for COI, 1.336–23.434% for 12S, and 7.897–71.862% for Dloop). These values were comparable to or smaller than those between species of the genus Panulirus, indicating that integration of mtDNA into the nuclear genome is a continuous and dynamic process throughout pre- and post-speciation events. Double peaks in electropherograms obtained by direct nucleotide sequencing were attributed to common nucleotides shared by multiple NUMTs. Information on the heteroplasmy and NUMTs would be very important for addressing their impact on direct nucleotide sequencing and for quality control of nucleotide sequences obtained.

Identification of putative neuropeptidergic signaling systems in the spiny lobster, Panulirus argus.

Members of the decapod infraorder Achelata, specifically species from the genus Panulirus, have storied histories as models for investigating the basic principles governing the generation, maintenance, and modulation of rhythmic motor behavior, including modulation by locally released and circulating peptides. Despite their contributions to our understanding of peptidergic neuromodulation, little is known about the identity of the native neuropeptides and neuronal peptide receptors present in these crustaceans. Here, a Panulirus argus nervous system-specific transcriptome was used to help fill this void, providing insight into the neuropeptidome and neuronal peptide receptome of this species. A neuropeptidome consisting of 266 distinct peptides was predicted using the P. argus assembly, 128 having structures placing them into a generally recognized arthropod peptide family: agatoxin-like peptide, allatostatin A (AST-A), allatostatin B, allatostatin C, bursicon, CCHamide, crustacean cardioactive peptide, crustacean hyperglycemic hormone/molt-inhibiting hormone, diuretic hormone 31 (DH31), ecdysis-triggering hormone (ETH), FMRFamide-like peptide (FLP), glycoprotein hormone (GPH), GSEFLamide, inotocin, leucokinin, myosuppressin, natalisin, neuroparsin, neuropeptide F, orcokinin, orcomyotropin, periviscerokinin, pigment-dispersing hormone, pyrokinin, red pigment-concentrating hormone, RYamide, short neuropeptide F (sNPF), SIFamide, sulfakinin, tachykinin-related peptide (TRP), and trissin. Twenty-five putative neuronal receptors, encompassing 15 peptide groups, were also identified from the P. argus transcriptome: AST-A, bursicon, CCHamide, DH31, diuretic hormone 44, ETH, FLP, GPH, inotocin, insulin-like peptide, myosuppressin, natalisin, periviscerokinin, sNPF, and TRP. Collectively, the reported data provide a powerful resource for expanding studies of neuropeptidergic control of physiology and behavior in members of the genus Panulirus specifically, and decapods generally.

Biodiversity of lobster larvae (Panulirus spp.) from the Indonesian Eastern Indian Ocean

Lobster fisheries play an important role in the development of Indonesian fisheries management. The tropical lobster genus Panulirus has high species diversity in the Indonesian Eastern Indian Ocean. The Indonesian government has designated lobster fisheries as one of the types of fisheries requiring special attention in 11 of the Fisheries Management Areas in the Republic of Indonesia (FMARI). Each management area has specific ecological characteristics and may have unique lobster species richness. Studies on the temporal and spatial distribution of lobster species during all life phases are necessary to determine the connectivity of lobster populations. This study aimed to identify the species of lobster larvae of the genus Panulirus in FMARI 573. Samples were collected from several locations, including Pacitan, Trenggalek, Tulungagung, Banyuwangi, and Lombok, in July-August 2018. Data were analysed descriptively through species identification based on morphological traits. Identification of the samples was carried out at the sampling site and in the laboratory. The study found six species of lobster larvae: Panulirus ornatus (local name udang mutiara), P. homarus (udang pasir), P. penicillatus (udang batu), P. versicolor (udang bambu), P. longipes (udang batik) and P. polyphagus (udang Pakistan). These species were unevenly distributed at the study sites. Further research is needed to analyse the distribution and connectivity of lobster populations by analysing species composition during different life phases (larva/puerulus, juvenile, adult) at different spatial and temporal scales.

Dynamic spatial allocation of scalloped spiny lobster (Panulirus homarus) in the coast of Gunungkidul, Indonesia

The Scalloped Spiny Lobster (Panulirus homarus) is the most caught species of the genus Panulirus in the coastal waters of Gunungkidul. As a result of the high economic value of this species, its catch rate continues to increase. The management of lobster fishery is less precise when using conventional bioeconomic models due to several things, among others are the distribution of its stock is spread according to spatial distribution, low levels of fish resource mobility and the tendency to be biased if the spatial aspects are not taken into account. Growth, mortality, and recruitment parameters are also highly dependent on environmental conditions albeit within a small distance. A spatial bioeconomic approach was carried out to assess a utilization optimization model, by taking into account the biological, ecological, and economic characteristics of this species' capture. This research was carried out in six lobster landing locations in Gunungkidul District, Yogyakarta, Indonesia. Catchability, fuel price, selling price, total cost, and total revenue from each lobster landing locations were identified to determine the dynamic spatial allocation of fishing effort. We found that the capture of P. homarus in four lobster landing locations (Gesing, Ngerenehan, Siung, and Sadeng) can be optimized during peak catch seasons, while in Gesing and Siung can be optimized during catch drought seasons.

Sound production mechanism in the Brazilian spiny lobsters (Family Palinuridae)

Strident lobsters of the Palinuridae family emit sounds in the presence of predators that can be used in the acoustic monitoring of such species. This study aims to identify sound emission and describe the structures of sound mechanism in red (Panulirus meripurpuratus) and green (Panulirus laevicauda) Brazilian spiny lobsters. The lobsters were collected in the environment, and recordings were performed in laboratory tanks with submerged hydrophones. The animals were stimulated to emit sound by the presence of an artificial octopus in the tank. The sounds emitted by the lobsters were analyzed by means of the waveform, and the structures involved (plectrum and file) were observed using scanning electron microscopy (SEM). Both species emitted a rasp sound composed of several pulses, with a rate varying from 125 to 265 pulses per second. The SEM showed that the file is similar between the species and it is covered by microscopic plates (shingles) measuring between 12.6 and 12.9 μm of medial–lateral width and 6.2 μm and 7.1 μm of anteroposterior length. This analysis also revealed for the first time the presence of pores (< 1 μm in diameter) with vestiges of cuticular setae in-between the shingles, which could be involved in the mechanosensory control of sound production in lobsters. The results of this study corroborate the morphological pattern of sound emission structure described for other lobsters of the genus Panulirus.

The Suitable COI Marker for Lobster of Genus Panulirus

This study was conducted to analyze the COI (cytchrome oxidase subunit-1) sequences of members of the genus Panulirus, and determine the best region to use for species identification through DNA barcoding. Six samples were collected randomly from five sites in Indonesia. The three lobster species collected were P. femoristriga (Padang), P. homarus (Malang), and P. versicolor. A total of 1,516 sequences were analyzed using the software MEGA 6 for covering alignment, nucleotide variation, mutationrates, and genetic distance. Samples classified in the upper region (UR) consisted of 25 Panulirus species and 17 undetermined species, while samples classified in the lower region (LR) consisted of 11 Panulirus species and 2 undetermined species.

Biodiversity of Lobster (Panulirus) from Eastern Indian Ocean of Indonesia Waters

Lobster fisheries play a very important role in the development of Indonesian fisheries management. Lobster fishing for Indonesian people plays a role in the economic, social and political fields. The key reason for this important role is because lobster fisheries are dominated by small-scale fishermen. Lobster also has ecological functions that play a key role in a benthic aquatic ecosystem. Tropical lobsters in the Panulirus group in Indonesian waters (Eastern Indian Ocean) are the most species and have high endemic levels. It is reasonable if the Indonesian government makes lobster fisheries as one of the fisheries groups that need to be considered in its territorial fisheries management (FMARI: Fisheries Management Area of the Republic of Indonesia). Each management area has different ecological characteristics. Differences in ecological conditions will cause differences in the composition of lobster species. For the sake of lobster fisheries management in each region, it is necessary to specify indicator species on the spatial and temporal scale. This study aims to identify lobster species of the genus Panulirus in the FMARI 573 eastern part of Indonesian waters. Data retrieval is done by taking samples from lobster fishermen. Sampling locations include Kebumen, Trenggalek, Blitar, Lumajang, Jember, and Sumenep. The sampling time was carried out in August-September 2018. Data was analyzed descriptively by identifying morphologically and recording the number of individuals per species. Identification of samples is carried out at the study site and also in the laboratory. The study found six lobster species, namely: Panulirus ornatus (Udang mutiara), P. homarus (U. pasir), P. penicillatus (U. batu), P. versicolor (U. bambu), P. longipes (U. batik) and P. polyphagus (U. pakistan) with the type of sand most often found among the study sites. Further research needs to be done to look at the distribution and connectivity of lobster populations by analyzing species variation in each life phase (larvae / puerullus, juvenile, adult) at a certain space and time scale.

White spot syndrome virus and the Caribbean spiny lobster, Panulirus argus: Susceptibility and behavioral immunity.

The Caribbean spiny lobster Panulirus argus is susceptible to infection by Panulirus argus Virus 1 (PaV1), the only virus known to naturally infect any lobster species. However, P. argus is able to mitigate PaV1 transmission risk by avoiding infected individuals. P. argus may also be susceptible to another lethal virus, White Spot Syndrome Virus (WSSV). WSSV has not been documented in wild populations of spiny lobsters, but has been experimentally transmitted to six other lobster species from the genus Panulirus. Although WSSV has been detected intermittently in wild populations of shrimp in the Caribbean region, the risk to P. argus has not been evaluated. Potential emergence of the disease could result in fisheries losses and ecological disruption. To assess the risk to P. argus, we tested its susceptibility to WSSV via injection and waterborne transmission. We also tested whether healthy lobsters can detect and avoid conspecifics with qPCR-quantifiable WSSV infections. We found P. argus to be highly susceptible to WSSV via intramuscular injection, with mortality reaching 88% four weeks post inoculation. Panulirus argus was also susceptible to WSSV via waterborne transmission, but WSSV burden was low after four weeks via qPCR. Behavioral assays indicated that P. argus can detect and avoid conspecifics infected with WSSV and the avoidance response was strongest for the most heavily infected individuals - a response comparable to PaV1-infected conspecifics. Panulirus argus is the first spiny lobster found to be susceptible to WSSV in the Americas, but it is possible that a generalized avoidance response by healthy lobsters against infected conspecifics provides a behavioral defense and may reduce WSSV infection potential and prevalence. Preliminary evidence suggests that the infiltration of hemolymph constituents into the urine may be the source of the avoidance behavior and could therefore extend to other directly transmitted pathogens in spiny lobster populations preventing them from becoming common in their population.

Genetic biodiversity of spiny lobsters (Panulirus spp.) from coastal waters of Southern Java, Indonesia

Abstract. Haryono FED, Ambariyanto. 2018. Genetic biodiversity of spiny lobsters (Panulirus spp.) from coastal waters of Southern Java, Indonesia. Ocean Life 2: 73-78. Spiny lobsters of the genus Panulirus inhabit the southern Java, however, species identification of early life-stages based on morphological features analysis is equivocal. The condition as result of differences in morphology of the larval stage and the adult, a long period of larval life cycle, impact of oceanographic currents inhibit and restrict the route and direction of larval dispersal that causes genetic changes. However, genetic biodiversity of spiny lobsters from this area has not been investigated. The aim of this/our study was to identified genetic diversity of lobsters in Southern Java waters. The research was conducted from January through to August 2015. A total of 1137 lobsters were collected from seven different locations for morphological analyses and 40 lobsters were taken randomly for genetic analysis. Observations nuclear and mitochondrial DNA, and the relationships of genetic in phylogenetic using Codon of code and MEGA 5.0, and dendogram using Primer_e software. Morphological analysis obtained 6 species of spiny lobsters: P. homarus, P. versicolor, P. ornatus, P. penicillatus, P. polyphagus and P. longipes. Phylogenetic analysis obtained two clades and morphological identification results obtained P. penicillatus (spiny rock lobster), but the identification genetically acquired included in a group of genetic P. homarus (spiny sand lobster). Such discrepancies are possibly due to a long period of larval life, adult in low light of intensity environment and an extreme of oceanographic conditions with marine oil spill.

A preliminary study on the distribution of spiny lobster (Panulirus spp.) in Labuan Island, Malaysia

Limited info regarding on the global distribution and fisheries data on the spiny lobster Panulirus spp. had placed the IUCN redlist in a dilemmatic position in determining the concrete status for proper conservation. The present survey was carried out in the western region of the main island which consists of seven random stations along the west coast of Labuan during day dive. An extreme low density of the spiny lobsters from the genus Panulirus was determined throughout the present study. Only four individuals of two spiny lobsters species were recorded. Two individuals of P. versicolor were observed in station 2 while the other two (P. ornatus) were spotted in station 4. Low numbers of the Panulirus spp. were spotted during the present preliminary survey was probably due to day dive sampling. Spiny lobster from the genus Panulirus tend to have a wide range of depth preference. Two adults P. versicolor were spotted in least turbid environment. In the previous studies, Panulirus spp. such as P. homarus, P. ornatus, and P. polyphagus tend to prefer slightly turbid environment. The results of the present preliminary daytime survey indicated only two species of Panulirus spp. recorded with two individual numbers per species in Labuan coastal waters. However, due to the little numbers of catchment during the preliminary survey, further studies need to be carried out to provide more concrete evidences on the depth preference of Panulirus spp. in Malaysian waters.

Differences in life-history and ecological traits between co-occurring Panulirus spiny lobsters (Decapoda, Palinuridae).

Coexistence of closely related species may be promoted by niche differentiation or result from interspecific trade-offs in life history and ecological traits that influence relative fitness differences and contribute to competitive inequalities. Although insufficient to prove coexistence, trait comparisons provide a first step to identify functional differences between co-occurring congeneric species in relation to mechanisms of coexistence. Here, a comparative review on life history and ecological traits is presented for two pairs of co-occurring species of spiny lobsters in the genus Panulirus: Panulirus gracilis and Panulirus inflatus from the Eastern Central Pacific region, and Panulirus argus and Panulirus guttatus from the Caribbean region. Panulirus gracilis and Panulirus inflatus have similar larval, postlarval, and adult sizes and a similar diet, but differ in degree of habitat specialization, fecundity, and growth rate. However, little is known on behavioral traits of these two species that may influence their competitive abilities and susceptibility to predators. The more abundant information on Panulirus argus and Panulirus guttatus shows that these two species differ more broadly in degree of habitat specialization, larval, postlarval and adult sizes, diet, fecundity, growth rate, degree of sociality, defense mechanisms, susceptibility to predators, and chemical ecology, suggesting a greater degree of niche differentiation between Panulirus argus and Panulirus guttatus than between Panulirus gracilis and Panulirus inflatus. Whether the substantial niche differentiation and apparent interspecific trade-offs between Panulirus argus and Panulirus guttatus relative to Panulirus gracilis and Panulirus inflatus reflect an earlier divergence of the former pair of species in the evolution of the genus constitutes an intriguing hypothesis. However, whether or not post-divergence evolution of each species pair occurred in sympatry remains uncertain.