Telson Length Research Articles

Population structure and feeding habits of Carcinoscorpius rotundicauda in the bay environment, Southern Gulf of Thailand

This study presents the first comprehensive assessment of the population structure and feeding habits of Carcinoscorpius rotundicauda in Thailand. Sample collection was conducted using crab gill nets at seven sampling sites characterized by distinct ecosystem attributes in Pattani Bay between February 2019 and March 2020. Our findings indicate the presence of a single Asian horseshoe crab (HSC) species within the bay, with a sex ratio of approximately 1:1 (48.1 % males, 51.9 % females) that did not deviate significantly from parity. Habitat variation within the bay did not influence HSC abundance (P > 0.05) whereas monthly abundance fluctuations were highly significant (P < 0.001), peaking in March and reaching the lowest in September. Positive correlations were observed between HSC abundance and environmental factors including dissolved oxygen, temperature, water pH, water depth, and chlorophyll c concentrations. Linear regression analysis revealed a positive correlation between morphometric characteristics and body weight. However, multiple linear regression analysis indicated a negative relationship between body weight and telson length (TEL) and opisthosoma width (OW) of males, as well as TEL of females. The size at which 50 % of the HSC population reached maturity (L50) was estimated to be 12.2 cm for males and 13.5 cm for females based on prosomal width (PW). The average PW measurements of HSC at different egg stages (1–4) from developing to mature females was 14.4 cm, with corresponding body weights ranging from 224 to 243 g. Females at egg of stages 3 and 4 were found throughout the year, indicating multiple spawning events, particularly prevalent in January-April, and predominantly abundant at stations 1, 2, 5 and 6. HSC primarily consumed bivalves (22.1±21.2 %), followed by fishes (5.9±13.0 %) and crustaceans (2.9±9.0 %) by volumetric contribution (%V). This comprehensive study provides novel insights into the population dynamics and feeding ecology of HSC within Thailand. The findings establish a foundational framework for future research endeavors and offer critical data to inform the management and conservation of their habitats.

Lost but not forgotten: Rediscovery of the Ukrainian Lepidurus middendorffii (Braem, 1893) (Branchiopoda: Notostraca) through integrative taxonomy

Abstract The taxonomy of the notostracan LepidurusLeach, 1819 is complicated by a large number of synonymised species and extensive intraspecific variability in many relevant characters. We demonstrate, based on an integrative taxonomic approach, that the Ukrainian populations of Lepidurus are not conspecific with any currently accepted Lepidurus species and assign them to the previously synonymised species Lepidurus middendorffiicomp. nov. (Braem, 1893). This species exemplarily highlights the problems in the taxonomy of Lepidurus. The species was originally described as Apus extensus var. middendorffii (Braem, 1893), but L. extensus is a junior synonym of Lepidurus lubbocki (Brauer, 1873), which is currently treated as a subspecies of Lepidurus apus (Linnaeus, 1758). Our molecular genetic analyses based on mitochondrial COI, 12S, 16S, and nuclear 28S, which included published data, suggest the presence of further, possibly cryptic species that await formal recognition and stress the importance for a more extensive revision of Lepidurus. The original type specimens of L. middendorffii, previously stored at the Museum of Natural History (Wrocław University, Wrocław, Poland), are lost and a neotype is designated. Lepidurus middendorffii is characterised by the dorsal organ position between the ocular tubercle margins, the sharp carapace sulcus spines, the long supra-anal plate with many median spines, a telson length to carapace length ratio 0.18–0.35, and differs by &amp;gt; 9% uncorrected COI p-distances from all other Lepidurus species.

Comparative morphological analysis of telson and uropods in Penaeus canaliculatus (Olivier, 1811), Penaeus semisulcatus (De Haan, 1844), and Metapenaeus stebbingi (Nobili, 1904) using scanning electron microscopy and EDX analysis

The telson and uropods collectively form the tail fan, playing crucial roles in locomotion, buoyancy, defense, and respiration. We aimed to compare telson and uropod structures in three shrimp species—Penaeus canaliculatus, Penaeus semisulcatus, and Metapenaeus stebbingi—to identify the species with the most robust telson for its environment. Our analysis involved morphological measurements and scanning electron microscopy (SEM), supplemented by a novel approach—Energy-Dispersive X-ray (EDX) spectroscopy, a technique not previously utilized in studies on these three species. M. stebbingi exhibited the longest telson length, whereas P. semisulcatus had the longest uropod. P. canaliculatus featured a single pair of fixed spines, while P. semisulcatus had evenly spaced small conical spines along the sides of the median elevation and groove. A distinctive feature of M. stebbingi was the telson, which had three pairs of large spines. Diverse setae on telsons included simple, unipennate, and plumose setae. Notably, specialized branched tubular setae on uropods' endopods may aid in grooming or swimming behavior. EDX spectroscopy revealed that the telson cuticle primarily consists of carbon, nitrogen, and oxygen, with significantly high concentrations alongside comparatively lower calcium and phosphorous concentrations. P. semisulcatus exhibited the highest calcium and phosphorus content among the three species. In conclusion, M. stebbingi's telson is structurally robust, emphasizing the importance of morphology, while P. semisulcatus demonstrated a hard telson through EDX analysis. Our study underscores not solely relying on morphology for telson strength assessment but considering telson composition. These variations among species may be attributed to diverse ecological and physiological adaptations.

Morphological and Habitat of Parhippolyte uveae Borradaile 1900 from Tanjung Sanjangan Central Sulawesi

Parhippolyte uveae is a type of shrimp found in the Tanjung Sanjangan Tolitoli area, Central Sulawesi. The availability of red shrimp morphology and habitat data completes basic information, which is important in the sustainable management of the species. This research aims to describe the morphology and habitat of red shrimp from Tanjung Sanjangan, Tolitoli, Central Sulawesi. The sampling method uses a purposive sampling method with 5 sampling stations. The environmental parameters measured are temperature, salinity, pH, and substrate observations. The measurement results show temperatures ranging between 27.9°C -29.9°C, salinity 15-17 ppm, pH 6.29- 6.82 with coral, mud, and sand as a substrate. Morphometric data shows that the samples have a Total Length (PT) between 26-46.85 mm. Abdominal Length 18.3-30.4 mm, Carapace Length (PK) 7.5-13 mm, Carapace Width (LK) 5.25-9.5 mm, Rostrum Length (PR) 1.6-3.4 mm, Telson Length (PTel) 4.45-7.2 mm, First Abdominal Length (PabP) 1.4-2.15 mm and Second Abdominal Length (PabK) ranges from 1.8-4 mm. Meristic data shows that the Tanjung Sanjangan red shrimp has 3 upper rostrum teeth and 3-5 lower rostrum teeth, 3 pairs of dorsal spines, and 2 pairs of posterior spines. The results of these character observations are by the description of the P. uveae species.

STUDI MORFOMETRIK UDANG BERAS MERAH (Metapenaeopsis palmensis) YANG TERTANGKAP PADA MALAM HARI DI PERAIRAN SAMBOJA KABUPATEN KUTAI KARTANEGARA

Southern Velvet Shrimp (Metapenaeopsis palmensis) of the Penaeidae family, morphometric measurements were carried out to see things that affect the shape of the species. This study was aimed to provide information about the morphometric study of red rice shrimp (Metapenaeopsis palmensis) caught at night in Samboja waters, Kutai Kartanegara. This research was conducted in October-November 2021, the sample used was 300 brown rice shrimp (Metapenaeopsis palmensis). The morphometric study used covariance analysis to look at 20 morphometric covariates that affect the total length (PTO). Based on the results of univariate anova test analysis, it is known that 20 morphometrics have a sig &lt;0.05, which means that H1 is accepted, which means it has an effect on PTO. Furthermore, ancova analysis was carried out, 13 morphometric results were obtained which had sig &lt;0.05 for PTO, namely rostrum length (RST), head length (PK), first segment length (PRP), second segment length (PRD), third segment length ( PRT), fourth segment length (PRE), fifth segment length (PRL), sixth segment length (PRN), headless length (PTK), telson length (TLN), carapace button length (PKB), third lower segment length (PTB) ), and the length of the fifth lower segment (PLB).

Morphological and molecular approaches revealed a new species of snapping shrimp genus Alpheus Fabricius, 1798 (Decapoda: Caridea: Alpheidae) from Lakshadweep Islands, India

A new species of the alpheid genus Alpheus Fabricius, 1798, Alpheus sulcipalma sp. nov., is described and illustrated based on the specimens collected from the intertidal zone of Agatti Island, Lakshadweep, India at 0.5-1.0 m depth. This species belongs to the A. edwardsii group by absences of tooth in the orbital hoods and presence of compressed major chela with dorsal and ventral notches. Alpheus sulcipalma sp. nov. is morphologically closely related with A. pacificus Dana, 1852, absence of balaeniceps crests in the minor chela and absences of spine in the merus of major pereiopod of both sexes. However, the new species differs from A. pacificus in presence of strong and broad triangular groove on the dorsolateral and dorsomesial surface of the palm of major chela; length ratio and armature of fingers and palm of minor chela, carpus segments of second and third pereiopods and telson length. The results of phylogenetic analyses using partial sequences of mitochondrial COI gene data compared between A. sulcipalma sp. nov. with congener species which strongly support the description of new species with available limited sequences. The interspecific genetic divergences of the COI gene for A. sulcipalma sp. nov. and A. pacificus were observed higher in ranges (11.1-28.9%).

Morphometric and meristic diversity of the species Androctonus crassicauda (Olivier, 1807) (Scorpiones: Buthidae) in Saudi Arabia.

Intraspecific molecular and morphological variations among geographically isolated populations are useful for understanding the evolutionary processes, which is considered early stage of allopatric speciation. Also, the knowledge of the regional variation of scorpion venom composition is needed to improve antivenom therapeutic management. Androctonus crassicauda (Olivier, 1807) is the most common and medically important species in Arabia and the Middle East. Therefore, this study aimed to investigate the geographic morphological variation among A.crassicaudapopulations, regarding its geographical distribution in unexplored arid regions in Saudi Arabia. Samples were collected and examined morphologically under a dissecting microscope from different four eco-geographical regions. The results of ANOVA and multivariate statistical analyses provide strong evidence of geographical variation. The two populations from OTU3 and OUT4 showed the greatest degree of morphological difference from populations of OUT1 and OUT2. Each OTU3 and OTU4 populations showed significant speciation without overlapping in the two groups, while the remaining overlapped groups comprised two other populations. Several body variables influenced male separation, including carapace posterior width, metasoma 3rd length, and metasoma 2nd length. For females, telson length, metasoma 1st width, and sternite 7th width were highly influential variables. Such variation may suggest the existence of cryptic taxa within A. crassicauda populations in Saudi Arabia. Moreover, metasoma ratios can be used as good indicators in intraspecific variation studies of Scorpions.

STUDI MORFOMETRIK UDANG CENDANA (Metapenaeus brevicornis) YANG TERTANGKAP DI PERAIRAN SAMBOJA KABUPATEN KUTAI KARTANEGARA

Yellow Shrimp (M. brevicornis) is a type of shrimp caught by Samboja fishermen which has a fairly high economic value. This study aims to provide information about the morphomorphological study of Yellow Shrimp (M. brevicornis) caught in the waters of Samboja, Kutai Kartanegara. This research was conducted in the waters of Samboja, Kutai Kartanegara, in November-December 2021, the sample used was 300 Yellow Shrimp (M. brevicornis). Morphometric study onmorphometric study Yellow Shrimp (M. brevicornis) using analysis with analysis of covariance test (ANCOVA) to see 20 morphometric covariates that affect total length (PTO). Based on the results of the analysis of the univariate ANOVA test, it is known that 20 morphometrics have a sig value &lt;0.05, which means that H1 is accepted, that all morphometrics have an effect on PTO. Furthermore, ancova analysis was performed, obtained 5 morphometrics that have sig &lt; 0.05, namely head length (PK), first segment length (PRP), telson length (TLS), lower head length (PKB) and tail length (PE), so from the results of the ancova test analysis showed that the most significant morphometric effect on PTO was 5 morphometers.

Morphometric characteristics and condition indices of stone crayfish Austropotamobius torrentium (Shrank, 1803) from the Mlinska River

Regarded as a protected species on the IUCN list of endangered species, and classified as data deficient species, the stone crayfish (Austropotamobius torrentium) is one of the five European species from the Astacidae family that lives in freshwater ecosystems across Bosnia and Herzegovina. The aim of this study was to investigate the variability of selected morphometric characteristics of male and female crayfish of the A. torrentium species from the upper reaches of the Mlinska River. The crayfish were sampled in June 2021 when 62 individuals (22 males and 40 females) were caught. They were analyzed fresh in the field and in the laboratory. The treatment included the measurement of 12 morphometric features: total body length (TBL), weight (W), claw length (CLL), claw width (CLW), carapace length (CPL), carapace width (CPW), rostrum length (ROL), rostrum width (ROW), abdominal length and width (ABL, ABW) and telson length and width (TEL, TEW). The mean body length ± SD was 79.05 ± 7.35 in males and 60.54 ± 10.03 mm in females. The mean recorded body weight ± SD was 17.51 ± 8.3 g in males and 7.02 ± 4.41 g in females. Using the linear regression method, a positive correlation was found between body length and weight (♂ R2=0.7644; ♀ R2=0.8222), body weight and claws length (♂ R2=0.876; ♀ R2=0.9661), as well as carapace width and body length (♂ R2=0.7216; ♀ R2=0.8411). Using the T-test, a statistically significant difference of the analyzed morphometric parameters was found between the sexes, which is explained by the pronounced sexual dimorphism of stone crayfish. The calculated values for Condition factor and the Crayfish constant indicate that the males are of better fitness, which is in line with the results of previous research in Europe. Data presented in this paper can serve as a basis for further research of A. torrentium in this area.

Morphometric variation of the horseshoe crab Tachypleus gigas (Xiphosura: Limulidae) from the Banyuasin estuarine of South Sumatra, Indonesia

Abstract. Fauziyah, Mustopa AZ, Fatimah, Purwiyanto AIS, Rozirwan, Agustriani F, Putri WAE. 2021. Morphometric variation of the horseshoe crab Tachypleus gigas (Xiphosura: Limulidae) from the Banyuasin estuarine of South Sumatra, Indonesia. Biodiversitas 22: 5061-5070. Morphological studies are essential for fish resource management, ecology, conservation, and stock assessment. This research was conducted to characterize the morphological variation of the coastal horseshoe crab (Tachypleus gigas) from the Banyuasin estuarine, South Sumatra, Indonesia. The body weight (BW), prosoma width (PW), carapace length (CL), telson length (TEL), and total length (TL) were measured for describing the morphometric variability of T. gigas. A total of 70 T. gigas (32 females and 38 males) were found using trammel net fishing and bottom gillnet during the survey. Multivariate and allometric methods analyzed their morphometric characters. Based on Kruskal- Wallis tests, the result showed a significant difference in somebody measurements (TL and CL) between males and females. The principal component analysis (PCA) results showed that all morphometric characters had a strong correlation in both sexes, so the first principal component (PC1) values were 92% and 72%. In comparison, the second principal component (PC2) values were 5% and 20% in females and males, respectively. The results of discriminant function analysis (DFA) suggested that only one (BW) of the five morphometric characters was significant in separating both sexes. Both sexes were also revealed variations in growth patterns based on the allometric analysis results. These results were expected to be used as a basis for managing the horseshoe crab population-based conservation.

Static allometry and sexual dimorphism in the Striped Lesser-thicktail Scorpion Uroplectes lineatus

Scorpions exhibit extreme forms of sexual dimorphism, with a number of recent studies highlighting general patterns. Explanations surrounding the potential drivers of these patterns remain speculative, even though static allometry offers a method for testing specific hypotheses. Importantly, a recent study describes a method of reference character choice when investigating sexual dimorphism and static allometry in scorpions. Here, commonly measured morphometric characters are used to investigate patterns of sexual dimorphism and static allometry in the South African scorpion Uroplectes lineatus C. L. Koch, 1844. Several analyses were used to select telson length as the sexually neutral reference character. Sexual body component dimorphism characterises U. lineatus males, while females generally display sexual size dimorphism. Similar patterns of static allometry characterise both sexes, with negative allometry retrieved for most characters, while three characters display positive allometry. For negatively allometry characters, inter-sexual selection likely favours a standard size of body parts in the population to facilitate inter-sexual interaction during courtship. In contrast, positively allometric characters may be under intrasexual selection, following the utility of features during contests. Even so, the differences in allometric slopes between the sexes indicate the possible functions of male features during courtship, while the female morphology is adapted to enhance reproductive output and parental care. Here, we demonstrate that a set of verification analyses may be effective in choosing an appropriate neutral reference character, but the selective forces which shape scorpion morphology are complex, and standardized methods need to be established to allow for robust inferences and inter-study comparability.

Análisis morfológico y morfométrico deTityus (Tityus) sorataensisKraepelin 1911 (Escorpionida: Buthidae) de dos valles mesotérmicos andinos, Quime y Cheje, La Paz-Bolivia

Around 2000 species of scorpions divided into 22 families were described in the world. In Bolivia, the scorpions of the family Buthidae are represented by the genus Tityus. The objective of this work is to perform a morpho-logical-morphometric characterization of intraspecific lineages Tityus (Tityus) sorataensis Kraepelin 1911 from two communities of La Paz-Bolivia. 85 samples of Tityus (Tityus) sorataensis from the scientific collection of the INLASA Antivenin Production Laboratory were used. With these, a morphological description was made at the level of species and morphotypes, as well as a traditional morphometric description with 34 variables. The variables were analyzed with the Statistica 7 and JMP programs, in which principal component analysis (PCA) and generalized discriminant analysis (AGD) were performed. It was found that Tityus (Tityus) sorataensis presents six morphotypes for Chime Q, Z, X, Y, G, R and three for Cheje Y, G, R. Sexual dimorphism was found in morphotypes, X, G, R. It was observed that excluding the diagnostic meristic variables, there was still differentiation at the morphometric level. Ten diagnostic phenotypic morphometric variables were identified among all our analyzes: prosome length, median prosome width, posterior prosome width, first lateral eye to median eyes, median eyepiece width, length of caudal segment II, width of caudal segment II, length of caudal segment III, telson length and length of the metasoma.

Survey and Morphological Studies on Scorpions Inhabiting New Valley Governorate, Egypt

The main objective of the present study is to make a survey on scorpion species inhabiting New Valley governorate, Egypt as well as to make some morphometric measurements on the recorded species and to design a key for the recorded species. To achieve the aims of the study, random samples were collected during the period from April to July, 2017 and from July to September, 2019. The study revealed the presence of four scorpion species belonging to family Buthidae namely: Leiurus quinquestriatus, Androctonus amoreuxi, Orthochirus innesi and Buthacusleptochelys. The study provides a key for the identification of the species and some morphometric measurements. The morphometric measurements included: Carapace length, Mesosoma length, Metasoma length, Telson length, Aculeus length, Vesicle length, Pedipalp femur length, Pedipalp patella length, Pedipalp chela length and total body length. The study revealed significant differences between the recorded four species. It also revealed significant differences between males and females of each species.

The morphometric variability of the mangrove horseshoe crab (Carcinoscorpius rotundicauda) from Banyuasin estuarine of South Sumatra, Indonesia

The allometric analysis was applied to record the morphometric variability in different sex of the mangrove horseshoe crab (Carcinoscorpius rotundicauda) collected from Banyuasin estuarine of South Sumatra, Indonesia during July 2019. The body parameter measurement of body weight (BW), total length (TL), prosoma width (PW), carapace length (CL), and telson length (TL) were recorded then pooled refer to the sex. The differences in each body parameter between the males and females were observed through the Student's t-test. The length/width-weight relationship for both sexes was analyzed using the power equations while the width/length-length relationship was analyzed using the linear equations. The Student’s t-test was used to determine significant differences from the isometric value. The females of C. rotundicauda were significantly heavier and larger in size than males except for telson length (p &lt; 0.05). Both sexes revealed a negative allometric growth for the TL/CL-BW relationships while the males indicated a negative allometric growth but the females indicated an isometric growth for the PW-BW relationships. Both sexes also indicated the isometric growth for the CL-PW relationship. The TL-PW/TEL relationship also revealed a negative allometric growth for both sexes. The study results were expected to be used as baseline data for the horseshoe crab management plan and action.

Delimitation of sympatric Palaemon (Decapoda, Palaemonidae) species of the Laguna Madre, Mexico

AbstractGrass shrimps Palaemon mundusnovus, P. pugio and P. vulgaris sympatrically inhabit in the Laguna Madre, Mexico. They exhibit very close morphological similarity and overlap in their diagnostic characteristics, which has hindered certainty in their identification and has raised doubt regarding their taxonomic validity. In this work, we analyse intra‐ and interspecific morphometric and meristic variability through a multivariate analysis, and we determine the molecular variation using mitochondrial sequences of the 12S, 16S and COX1 genes to confirm the validity of the three taxa as having distinct lineages or to recognize a smaller number of species with phenotypic plasticity. Our results corroborate the taxonomic validity of the three species; however, there is intraspecific plasticity, interspecific overlap of characteristics and greater morphological and molecular similarity between the species P. mundusnovus and P. pugio, whereas P. vulgaris was better delimited. These species form a monophyletic group but the phylogenetic relationship obtained is discussed. Telson length was the primary variable in the principal components analysis, whereas the length of the propodus of the second pereiopod was the best discriminant. The range of variation reported in the characteristics linked to the rostrum is extended, and its influence on the separation of these species is recognized. The joint application of multivariate analysis from morphological variables and molecular tools is recommended to clarify the taxonomic status of species featuring close morphological similarity and sympatric distribution.

Phyllocarid crustaceans from the Late Devonian of the Kowala quarry (Holy Cross Mountains, central Poland)

AbstractPhyllocarida (Crustacea, Malacostraca) are among the most diversified and widespread Late Devonian arthropods. Although previous studies mention phyllocarid fossils from Late Devonian (Frasnian and Famennian) deposits of the Holy Cross Mountains of south‐central Poland, phyllocarids from the Kowala quarry have not been systematically described. Two new species are described from Kowala strata: Echinocaris bisulcata sp. nov. characterized by oval carapace valves with a short hinge line, cone‐like tubercules on the carapace anterior lobe, two pronounced lateral sulci (ventral and median) and two pairs of short spines on every abdominal segment; and Montecaris marynowskii sp. nov. characterized by two pairs of robust abdominal spines, a telson that is shorter than furcal rami, distal parts of which are parallel to the telson, and a body length approximately four times longer than the telson length. Additionally, an isolated furca identified as Dithyrocaris sp. is described herein. Damage observed in the holotype specimen of Montecaris marynowski sp. nov. is consistent with a healed injury, possibly caused by predatory fish. Notes concerning the global occurrences of montecaridids, echinocaridids and the genus Dithyrocaris in the Late Devonian are also provided.

Biodiversity and Distribution of Horseshoe Crabs in Northern Coast of Java and Southern Coast of Madura

Horseshoe crab is an important component of macro-benthos communities in the fine sand or mud substrate in coastal waters, both in the tropical and temperate region. This primitive animal consists of four species in the world, and three species can be found di Asian region, including Indonesia, namely Tachypleus tridentatus, T. gigas, and Carcinoscorpius rotundicauda. Scientific information about species distribution of three Asian horseshoe crab in Indonesia is limited, also about morphometric characters. This study aims to determine the morphometric characters and species distribution of three Asian horseshoe crab in north coast of Java and south coast of Madura Island. This study was conducted on July-August 2016. The total number of three Asian horseshoe crab obtained in this study was 260 individuals, distributed along north coast of Java and south coast of Madura Island, respectively 176 individuals of C. rotundicauda, 35 individuals of T. tridentatus, and 49 individuals of T. gigas. Tachypleus gigas has the largest size and widest class interval among three Asian horseshoe crab species. Morphometric characters is differences among three Asian horseshoe crab species. Carapace width and telson length were not significantly different among sampling locations only in T. tridentatus.

Variation in Morphometric Characters in Four Sand Crab (Albunea symmysta) Populations Collected from Sumatra and Java Island, Indonesia.

Variation in morphometric characters in four sand crab (Albunea symmysta) populations from four intertidal areas in Sumatra (Aceh and Bengkulu) and Java (Cilacap and Yogyakarta) were studied. Crabs collected from the four sites were measured to obtain 10 morphometric characters, i.e., carapace length (CL), carapace width (CW), ocular peduncle length and width (LOP and WOP), telson length and width (LT and WT), merus length (ML), carpus length (CaL), propodus length (PL), and dactylus length (DL). Allometric relationships were established among three morphometric characters (CW, PL, and DL) for each site, in which CL was fixed on the abscissa as a reference variable. The analysis of covariance showed that population from Yogyakarta had a greater carapace width and the Aceh population had a longer dactylus length. In terms of propodus length, the Aceh population had a longer dactylus length than the Bengkulu population. Two group populations were detected by cluster analysis with 10 morphometric characters, i.e., the Sumatra population and the Java population.

A new sponge associated shrimp species of the Indo-West Pacific genus Paraclimenaeus (Decapoda, Caridea, Palaemonidae)

A new sponge-associated species, Paraclimenaeus michaeli sp. nov. from Sulawesi, Indonesia, and Singapore, is described and illustrated. The new species can be distinguished from its congenerics by: (1) the downwards curved rostrum with 2 acute dorsal teeth subdistally, (2) the absence of subdistal teeth on the fixed finger of the major second chela, (3) the pairs of dorsal telson spines at about 0.33 and 0.66 of the telson length, (4) the caudal fan sparsely setose, and (5) the second pereiopods without subdistal teeth on fixed finger. To evaluate its relationship with congenerics and species of the related genera Apopontonia and Climeniperaeus, a phylogenetic analysis based on the 16S mitochondrial gene is presented. A key for the identification of the species in Apopontonia, Climeniperaeus and Paraclimenaeus is proposed.

Growth and Survival Variations of &lt;i&gt;Penaeus monodon&lt;/i&gt; from Six Breeding Families

The survival and growth of P. monodon from six breeding families were evaluated in this study. The morphometric traits, including the carapace length, carapace width, body length, telson length and body weight were measured throughout 108-days growth experiment. Ratios of the telson length and carapace width to body length, the length-weight relationship (LWR), condition factor (K), weight gained rate (WGR), specific weight rate (SWR), and survival of P. monodon were calculated. The testing traits were varied in selected breeding family. Length-weight relationships of family1 can be expressed as W = 0.0126BL 3.064 (R² = 0.9473) which had the biggest slope value (b). The equation W = 0.0563BL 2.417 (R² = 0.8318) belong to family2, while the slope value less than 3 indicates that the animal becomes slender as it increases in length. The order of the survival rate was family4 > family1 > family2 > family3 > family6 > family5.The order of the specific weight rate and weight gain rate was family6 > family4 > family2 > family5 > family3 > family1. In comparison of the condition factor between different families, the highest condition factor (1.57) was observed in the family5, and the lowest condition factor (1.40) was the family6. According to above indexes, rearing performance of family4 was the best in the tested breeding families in this study.