Contrasting strategies of osmotic and ionic regulation in freshwater crabs and shrimps: gene expression of gill ion transporters.

Owing to their extraordinary niche diversity, the Crustacea are ideal for comprehending the evolution of osmoregulation. The processes that effect systemic hydro-electrolytic homeostasis maintain hemolymph ionic composition via membrane transporters located in highly specialized gill ionocytes. We evaluated physiological and molecular hyper- and hypo-osmoregulatory mechanisms in two phylogenetically distant, freshwater crustaceans, the crab Dilocarcinus pagei and the shrimp Macrobrachium jelskii, when osmotically challenged for up to 10 days. When in distilled water, D. pagei survived without mortality, hemolymph osmolality and [Cl-] increased briefly, stabilizing at initial values, while [Na+] decreased continually. Expression of gill V-type H+-ATPase (V-ATPase), Na+/K+-ATPase and Na+/K+/2Cl- symporter genes was unchanged. In M. jelskii, hemolymph osmolality, [Cl-] and [Na+] decreased continually for 12 h, the shrimps surviving only around 15-24 h exposure. Gill transporter gene expression increased 2- to 5-fold. After 10 days exposure to brackish water (25‰S), D. pagei was isosmotic, iso-chloremic and iso-natriuremic. Gill V-ATPase expression decreased while Na+/K+-ATPase and Na+/K+/2Cl- symporter expression was unchanged. In M. jelskii (20‰S), hemolymph was hypo-regulated, particularly [Cl-]. Transporter expression initially increased 3- to 12-fold, declining to control values. Gill V-ATPase expression underlies the ability of D. pagei to survive in fresh water while V-ATPase, Na+/K+-ATPase and Na+/K+/2Cl- symporter expression enables M. jelskii to confront hyper/hypo-osmotic challenges. These findings reveal divergent responses in two unrelated crustaceans inhabiting a similar osmotic niche. While D. pagei does not secrete salt, tolerating elevated cellular isosmoticity, M. jelskii exhibits clear hypo-osmoregulatory ability. Each species has evolved distinct strategies at the transcriptional and systemic levels during its adaptation to fresh water.

Acclimation to cyclic hypoxia improves thermal tolerance and copper survival in the caridean shrimp Palaemon varians.

In response to the continuous variation of environmental parameters, species must be able to adjust their physiology to overcome stressful conditions, a process known as acclimatization. Numerous laboratory studies have been conducted to understand and describe the mechanisms of acclimation to one environmental stressor (e.g. cyclic hypoxia), but currently our understanding of how acclimation to one stressor can change tolerance to a subsequent stressor is limited. Here, in two different experiments, we used the shrimp Palaemon varians to test how, following 28-days acclimation to cyclic hypoxia (mimicking a cyclic hypoxic regime currently found in its natural habitat), critical thermal maximum (CTmax) and sensitivity to copper (Cu2+) exposure (30 mgL-1) changed in comparison to shrimp acclimated to normoxic conditions and then exposed to thermal stress or Cu2+. Acclimation to cyclic hypoxia improved both CTmax (~1 °C higher than controls) and survival to acute Cu2+ exposure (~30% higher than controls) and induced significant gene expression changes (i.e. up-regulation of heat shock protein 70 - HSP70, hypoxia inducible factor - HIF, phosphoenolpyruvate carboxykinase - PEPCK, glucose 6-P transporter - G6Pt, metallothionein - Mt, and down-regulation of hemocyanin - Hem) in animals acclimated to cyclic hypoxia. Our results demonstrate how acclimation to cyclic hypoxia improved tolerance to subsequent stressors, highlighting the complexity of predicting organismal performance in variable (i.e. where multiple parameters can simultaneously change during the day) environments.

Two new species and a new record of Bopyrinae (Isopoda: Bopyridae) infesting Alpheidae and Hippolytidae, with comments on the genus Bopyrina Kossmann, 1881.

Two new bopyrids, Bopyrinina articulata n. sp. and Bopyrinella asymmetrica n. sp. are described from French Polynesia, the Red Sea, and the Philippines. Bopyrinina articulata n.sp. infests Salmoneus cf. gracilipes Miya, and is distinguishable from other species of this genus by the structure of the maxilliped, pleopods and oostegite 1. Bopyrinella asymmetrica n. sp. is most similar to Bopyrinella albida Shiino, 1958, but females differ from that species because all pereomeres on the short side have round dorsolateral bosses and its pleotelson is greatly distorted. Bopyrina ocellata (Czerniavsky, 1868) is newly recorded from the Western Atlantic, from Florida, USA. Review of the species of Bopyrina revealed that B. choprai Nierstrasz & Brender à Brandis, 1929 and B. sewelli Chopra, 1930 are intermediate in morphology between Bopyrina and Schizobopyrina, the taxonomic assignment of these two species needs further evaluation. Keys to Bopyrinella Nierstrasz & Brender à Brandis, 1925 and Bopyrina Kossmann, 1881 are presented. Hosts and distributions of the seven species of Bopyrinella are summarized.

Systematic analysis of the caridean shrimp superfamily Pandaloidea (Crustacea: Decapoda) based on molecular and morphological evidence.

One of the systematically controversial superfamilies in Caridea is the predominately deep-sea or cold water Pandaloidea, largely because this species-rich group of nearly 200 species in 25 genera exhibits a very high diversity of body forms and ecology. Although the relationships amongst the taxa within Pandaloidea have been repeatedly discussed based on morphology, no comprehensive molecular phylogeny exists. In this study, we present the first molecular phylogeny of the group, based on a combined dataset of two mitochondrial (12S and 16S rRNA) and six nuclear (ATP synthase ß-subunit, enolase, glyceraldehyde-3-phosphate dehydrogenase, histone 3, phosphoenolpyruvate carboxykinase and sodium-potassium ATPase α-subunit) markers, based on 62 species (about 1/3 of known biodiversity) in 22 genera (88% of genera) of two pandaloid families (Pandalidae, Thalassocarididae) and outgroups from seven other caridean families. With generally high support, the relationships within the clade are fully resolved. Pandalidae is shown to be paraphyletic with Thalassocarididae deeply nested within as a monophyletic group, and the latter is herein considered to be a synonym of Pandalidae. Five major clades are recovered, with the shallow water genera Anachlorocurtis, Chlorocurtis, Chlorotocella and Miropandalus forming a sister clade to the remaining genera. At the genus level, the phylogeny indicates Plesionika, Heterocarpus and Pandalus to be not monophyletic. The validity of Pandalopsis, Stylopandalus and Calipandalus is challenged and these genera are considered herein to be junior synonyms of Pandalus (Pandalopsis) and Plesionika (Stylopandalus and Calipandalus). Although not fully resolved, some evidence potentially considers Nothocaris to be a valid genus. Ancestral State Reconstruction successfully recovered 15 synapomorphies for the major clades, with 11 of them reported to be of systematic significance for the first time.

Morphology and DNA Data Reveal a New Shrimp Species of Genus Latreutes Stimpson, 1860 (Decapoda: Hippolytidae) from the Western Atlantic.

The genus Latreutes Stimpson, 1860 comprises 17 described species of marine shrimps, most of them distributed in the Indo-West Pacific and eastern Pacific. Only three species are recorded in the Atlantic. When comparing specimens of Latreutes parvulus (Stimpson, 1871) from both sides of the Atlantic by means of a combination of morphological and molecular data, we recognized a new species of Latreutes from Brazil (Rio Grande do Norte, Bahia, Rio de Janeiro and São Paulo). The phylogenetic tree generated on the basis of the 16S gene showed a clear separation of the specimens of the new species from the other closely related species analyzed. The analyses also evidenced that the new species and L. parvulus are sister taxa. Although very similar, both species can be easily separated by features of the scaphocerite and eyestalk. Rostrum form and dentition, characters usually used for L. parvulus recognition, were highly variable in both species. Thus, herein the new species is described, illustrated, and compared with morphological similar species of Latreutes. A key for the Atlantic species is also provided.

The androgenic gland in male morphotypes of the Amazon River prawn Macrobrachium amazonicum (Heller, 1862).

Sexual differentiation and primary and secondary sexual characteristics in male crustaceans are modulated by hormones produced in the androgenic gland (AG). The AG is also responsible for the determination of morphotypes in caridean shrimps, such as Macrobrachium amazonicum that shows four morphotypes: translucent claw (TC), cinnamon claw (CC), green claw 1 (GC1) and green claw 2 (GC2). Here, we verified the anatomical, histological and ultrastructural characteristics of the AG in different morphotypes of this species with both amphidromous and hololimnetic life cycles. In submissive morphotypes (TC and CC), the AGs are reduced and concentrated in the terminal expansion of the distal portion of vasa deferentia (DVD), the ejaculatory ducts (ED). In dominant morphotypes (GC1 and GC2) these glands lie along the DVD and ED. Two morphological stages (I and II) were recorded for AG cells. In submissive morphotypes stage I cells predominated in the AGs, while in dominant morphotypes stage II cells were more common. AG cells in both stages were positive for proteins, confirming the protein nature of the secreted hormone. Stage I cells have abundant rough endoplasmic reticulum (RER) with numerous parallel cisternae, whereas in stage II cells, the cisternae of RER are highly dilated. Stage II cells do not produce secretory granules, but they undergo hypertrophy and the hormone release to hemolymph probably occurs by holocrine secretion. The AGs in TC, GC1 and GC2 morphotypes increase as the animals grow and are larger in GC1 males. On the other hand, AGs decrease in the CC morphotype as the animal grows. These differences are related to the type of reproductive strategy adopted by each morphotype. In M. amazonicum, the AGs show the same morphological, histochemical and ultrastructural patterns between the different life history populations.

Molecular phylogeny of Pasiphaeidae (Crustacea, Decapoda, Caridea) reveals systematic incongruence of the current classification.

Caridean shrimps constitute one of the most diverse groups of decapod crustaceans, notwithstanding their poorly resolved infraordinal relationships. One of the systematically controversial families in Caridea is the predominantly pelagic Pasiphaeidae, comprises 101 species in seven genera. Pasiphaeidae species exhibit high morphological disparity, as well as ecological niche width, inhabiting shallow to very deep waters (>4000m). The present work presents the first molecular phylogeny of the family, based on a combined dataset of six mitochondrial and nuclear gene markers (12S rDNA, 16S rDNA, histone 3, sodium-potassium ATPase α-subunit, enolase and ATP synthase ß-subunit) from 33 species belonged to six genera of Pasiphaeidae with 19 species from 12 other caridean families as outgroup taxa. Maximum likelihood and Bayesian inference analyses conducted on the concatenated dataset of 2265bp suggest the family Pasiphaeidae is not monophyletic, with Psathyrocaris more closely related to other carideans than to the other five pasiphaeid genera included in this analysis. Leptochela occupies a sister position to the remaining genera and is genetically quite distant from them. At the generic level, the analysis supports the monophyly of Pasiphaea, Leptochela and Psathyrocaris, while Eupasiphae is shown to be paraphyletic, closely related to Parapasiphae and Glyphus. The present molecular result strongly implies that certain morphological characters used in the present systematic delineation within Pasiphaeidae may not be synapomorphies and the classification within the family needs to be urgently revised.

Phylogenetic relationships and adaptation in deep-sea carideans revealed by mitogenomes.

The deep-sea environment is characterized by extreme and inhospitable conditions, including oxygen depletion, low temperatures, high pressure, absence of light, and limited food availability. Mitochondria and mitogenomes play a crudial role in aerobic respiration to generate energy for eukaryotes. Here, using the Illumina Hiseq 4000 platform, we performed mitogenome sequencing for five deep-sea caridean species: Lebbeus shinkaiae, Lebbeus Formosus, Glyphocrangon regalis, Heterocarpus dorsalis, and Heterocarpus laevigatus, and five deep-sea caridean mitogenomes were assembled and identified. Each of the five mitogenomes contained 13 protein-coding genes, 2 rRNAs and 22 tRNAs. Specific elements, such as tandem repeats and AT-rich sequences, were observed in the control regions of Lebbeus formosus and Lebbeus shinkaiae, potentially take a role in regulating mitochondrial genome replication and transcription. The gene order of all obtained mitogenomes follows caridean ancestral type organization. Phylogenetic analysis shows a robustly supported phylogenetic tree for the infraorder Caridea. The monophyly of the families included in this study was strongly supported. This study supports the monophyly of Oplophoroidea, but rejects the monophyletic status of Nematocarcinoidea, Crangonoidea, and Alpheoidea. At the genus level, Plesionika is polyphyletic and Rimicaris is paraphyletic in our analysis. Furthermore, Paralebbeus may be considered invalid and synonymous with Lebbeus. Positive selection analysis reveals evidence for adaptive changes in the mitogenome of different deep-sea caridean lineages. Nine residues located in cox1, cox3, atp6, nad1, nad2, nad4, nad5, nad6 and cytb were determined to have undergone positive selection. Mitogenome of different deep-sea lineages experienced different positive selection, and the lineage represented by Alvinocarididae living in deep-sea hydrothermal vents experienced the strongest positive selection. This study provides valuable insights into the adaptive evolution of deep-sea shrimps at the mitochondrial, highlighting the mitogenomic strategy that contribute to their unique adaptations in the deep-sea environment.

Deep-sea caridean shrimps collected from the South China Sea with emphasizing their phylogenetic relationships.

Despite the high biological and ecological diversity of the South China Sea, limited research has been conducted on the deep-sea species diversity of caridean shrimps. Based on the collections from three scientific expeditions conducted in the South China Sea, 31 caridean species, belonging to nine families, were reported, including the identification of two species not previously documented in this region, namely Janicella spinicauda (A. Milne-Edwards, 1883) and Systellaspis curvispina Crosnier, 1988. In addition to morphological features, the COI and 16S gene sequences of these species were analyzed to assess their evolutionary relationships within each family. Phylogenetic analyses, with highest species coverage to date, indicated that similarity in morphological characteristics does not always lead to closer phylogenetic relationships and some defining characteristics for specific taxa are not always synapomorphies but may be the result of convergent evolution. Our results establish reliable evolutionary relationships within specific taxa and highlight the necessity for further taxonomic revisions within these taxa.

Male reproductive system of the freshwater prawn Macrobrachium brasiliense (Decapoda: Palaemonidae): Notes on spermatophore formation and sperm count.

Studies on the morphology of the reproductive system are essential for understanding the reproduction processes of species or even within genera or families. The present study aimed to describe the functional morphology of the male reproductive system, spermatophore formation, and sperm count of Macrobrachium brasiliense. The anatomy of the reproductive system consists of a pair of testes from which the vasa deferentia (VD) starts, extending to the fifth pair of pereopods. The VD is divided into three regions: proximal (PVD), middle (MVD), and distal (DVD). In the PVD, there is a prominent fold, the typhlosole, formed by columnar cells. The typhlosole disappears in the MVD, being incorporated into one of the faces of the VD wall, identified by its simple columnar epithelium while the remainder of the vessel wall is formed by squamous or simple cubic epithelium. Columnar cells produce type-II and III secretion. The epithelium in the DVD is made up only of cubic cells. Low sperm concentration was observed when compared to other species of the genus Macrobrachium. In conclusion, the typhlosole and columnar epithelium are responsible for the asymmetric spermatophore, which seems the pattern of Macrobrachium that is probably shared with other caridean shrimps.

Is there a trade-off between sperm production and sexual weaponry in the Amazon River prawn Macrobrachium amazonicum (Heller, 1862)?

The Amazon River prawn Macrobrachium amazonicum shows populations with four well-defined morphotypes in males. Dominant males of morphotypes green claw 1 (GC1) and green claw 2 (GC2) have large bodies and chelipeds and a higher reproductive success in comparison with the submissive morphotypes - translucent claw (TC) and cinnamon claw (CC). However, recently, some populations of the species do not have dominant morphotypes. Here, we compared the patterns of spermatic production and concentration among morphotypes and populations with three different phenotypes: (i) large-size amphidromous prawns, and (ii) large-size ("i" and "ii" with dominant morphotypes) and (iii) small-size hololimnetic prawns (without morphotypes). We described the spermatogenesis and the histochemical features of vasa deferentia (VD) and evaluated the relationship between the investment in spermatic production and sexual weapons acquisition in males of different phenotypes. The spermatic production and concentration in populations with four morphotypes were similar between morphotypes. The exception was the CC morphotype in which males had the seminiferous tubules filled with spermatocytes and low spermatic concentration. The spermatogenesis, spermiogenesis, and VD structure were not different among the studied phenotypes and populations. The seminal fluid of M. amazonicum is comprised by glycoproteins and by concentric layers of secretions of types I, II (basophilic), and III (eosinophilic). We could infer that males of dominant morphotypes allocate a higher amount of energy to the development of strong sexual weapons at the expense of the energy allocated to the reproductive system during the sequential growth. Inversely, small-size males direct more energy toward the spermatic production and transference at the expense of sexual weapons. Therefore, there is a clear trade-off between the investment in the gonadal and sexual weapons development in males of M. amazonicum.

A New Sponge Associated Shrimp of the Genus Periclimenaeus Borradaile, 1915 (Decapoda, Palaemonidae) from the Tropical Eastern Atlantic, Cabo Verde Islands.

A new species of the caridean shrimp genus Periclimenaeus is described from the Cabo Verde Islands, tropical eastern Atlantic. Periclimenaeus ramili sp. nov. is morphologically most similar to the north-eastern Atlantic P. aurae dos Santos, Calado & Araújo, 2008, the western Atlantic P. pearsei (Schmitt, 1932), and particularly the eastern Pacific P. hancocki Holthuis, 1951, all sharing many features, especially the reduced incisor process of the mandible, the general shape of the second pair of chelipeds and ambulatory pereiopods, and the telson armament. Based on these features, a new species group is established here to include these four species. Periclimenaeus ramili sp. nov. can be readily distinguished from P. aurae and P. pearsei by the shape of the dactylus of the first pereiopod chela. From P. hancocki, the new species can be distinguished, among other features, by the shorter rostrum armed with lower number of dorsal teeth, the relative length of the scaphocerite to the antennular peduncle, and by the slender distal articles of the third maxilliped. The new species is also reported to excavate its own burrows for living inside its sponge host, a behaviour previously unknown in species of the genus.

First record of the symbiotic palaemonid shrimp Pontonidessibogae Bruce, 2005 (Crustacea, Decapoda, Palaemonidae) from Korea.

Background: A single specimen of Pontonidessibogae was collected from a dendrophylliid coral by trimix SCUBA diving at a depth of 75 m during fieldwork around Jejudo Island, Korea in 2020. The morphology of the specimen corresponds closely to the main diagnostic characters of the holotype, especially in the presence of a distinct tubercle on the eyestalk, as well as the second pereiopod with fusiform setae along the dorsal border of the ischium. New information: The genus Pontonides had previously not been reported from Korean waters. Herein, colour photographs are provided, as well as an illustrated description including previously unreported characteristics.

Life History Traits of the Snapping Shrimp Alpheus carlae (Decapoda: Alpheidae) from the South-eastern Coast of Brazil.

The life history traits of the snapping shrimp Alpheus carlae were investigated. We evaluated the relative growth, morphological sexual maturity, sexual dimorphism, handedness, fecundity, and egg volume. Sampling was performed monthly in an estuarine region of Cananéia, in the south-eastern coast of Brazil. The following structures were measured to perform the relative growth analysis: length of carapace and second pleonal pleuron, length, width and height of major cheliped propodus, and length of appendix interna and appendix masculina. Juveniles and adults males and females have different growth patterns, indicating distinct strategies of energy allocation. The estimated carapace length at the onset of morphological sexual maturity of females and males was 5.6 mm and 6.2 mm, respectively. The sexual dimorphism of specific body structures was evident, mainly in the appendix interna of females and major cheliped of males. There was no evidence of handedness in females or males. The mean fecundity of females was 364 ± 204 eggs (mean ± SD) eggs and was positively correlated with the carapace length. The egg volume differed between developmental stages I and II, and I and III, with an overall volume increase of 73.23% and 95.45%, respectively. The results contribute to the knowledge about A. carlae and its life history in natural environment.

Redescription of Paraclimenes gorgonicola (Bruce, 1969) (Crustacea: Decapoda: Palaemonidae) and establishing P. franklini (Bruce, 1990) as its junior synonym.

The octocoral associated species Paraclimenes gorgonicola is a deep-sea palaemonid shrimp briefly described in Bruce (1969) without illustrations. Paraclimenes franklini, the type species of the genus Paraclimenes, has been considered as a valid species and distinguished from P. gorgonicola by the presence of articulated postrostral teeth on the carapace. Paraclimenes gorgonicola is herein fully redescribed and illustrated on the basis of the type series which is deposited in Naturalis Biodiversity Center, Leiden, The Netherlands and recently collected specimens from shallow waters around Jejudo Island, Korea, and compared with P. franklini. It is demonstrated that both taxa are conspecific and thus P. franklini is considered to be a junior synonym of P. gorgonicola.

Two New Species and a Further Country Record of the Caridean Shrimp Genus Periclimenaeus Borradaile, 1915 from Korea (Decapoda: Palaemonidae).

Two new species of the palaemonid genus Periclimenaeus are described and illustrated from Korea; additionally, a third species is recorded from Korea for the first time. Periclimenaeus karantina sp. nov. was obtained from ascidian hosts. The species has a denticulate dactylus on both second pereiopods, considered to be typical for ascidian associates. It can be separated from related species by the combination of the following characters: the carpocerite overreaching the anterior margin of the scaphocerite; the distolateral tooth of the scaphocerite exceeding the anterior margin of the lamella; the dactylus of the minor chela exceeding the fixed finger; and the ambulatory dactyli furnished with a minute proximal tooth. Periclimenaeus apomonosi sp. nov. was obtained from sponge hosts, and belongs to the P. robustus species-group, on account of the developed anterior median lobe on the tergite of the first abdominal somite. It can be distinguished from related species by the combination of the presence of a supraorbital tooth; the presence of a pointed process on the inferior orbital angle; the distolateral tooth of the scaphocerite terminating level with the anterior margin of the lamella; the antennal carpocerite reaching about 0.6 of the scaphocerite; the first and second chelae with non-serrated cutting edges; the ischium and merus of the second pereiopods harbouring tubercles on the ventral margin; and the ambulatory dactyli with a distal accessory tooth and the corpus furnished with denticles, ventrally. The sponge associated species, Periclimenaeus djboutensis, relatively widespread across the Indo-Pacific, is reported for the first time from Korea in Geomundo Island. Asides from a morphological description of all three species, molecular information of two genetic markers (16S + COI) is provided to aid in future phylogenetic reconstructions of the genus.

New record of the sponge-dwelling shrimp Typton distinctus Chace, 1972 (Decapoda: Caridea: Palaemonidae) in São Paulo State, Brazil.

Among the Caridea Infraorder, the palaemonid shrimp from the genus Typton Costa, 1844 are commonly found in association with sponges, frequently feeding on the tissues of their hosts ((Duris et al. 2011; Almeida et al. 2014; Pachelle et al. 2015; Soledade et al. 2017). Typton is mostly characterized by morphological features related to their sponge-dwelling lifestyle, as a simple and compressed rostrum, carapace smooth and antennal spines present, antennae extremely reduced and scaphocerite rudimentary. Mandible without palp, incisor process normal, reduced or absent. Second legs unequal, asymmetrical, without molar process on major chela (Bruce, 1972).

An updated checklist of caridean shrimps of the Persian Gulf and Gulf of Oman.

The material of the present checklist has been collected from the Iranian intertidal and shallow subtidal shores of the Persian Gulf and Gulf of Oman from 2015 to 2019, in addition to re-examining all the materials deposited in the Zoological Museum of the University of Tehran. This checklist providing 16 new records for the Persian Gulf and 15 for the Gulf of Oman raised the number of recorded caridean shrimps to 109 and 49 for these gulfs, respectively. However, the actual number of these shrimps are higher than these numbers due to two facts. Firstly, most of the subtidal diverse ecosystems, e.g. coral reefs and seagrass bed have not been seriously investigated taxonomically. Secondly, there are some members of species complexes and probably some new species in the study which need to be carefully treated.

Notes on some crinoid associated decapod crustaceans (Crustacea: Decapoda) of Lakshadweep Archipelago, Central Indian Ocean.

Decapod crustaceans symbiotic with echinoderms (sea stars, brittle stars, feather stars, basket stars, sea cucumbers, and sea urchins) possess remarkable diversification in the Indo-Pacific. In the present study, seven species of decapod crustaceans symbiotic with crinoids are recorded based on collections from selected Islands (Agatti, Amini, Bangaram, Kavaratti, Kalpeni, and Minicoy) of Lakshadweep Archipelago. Of these decapods, five caridean shrimps (Alpheidae: Synalpheus carinatus (de Man, 1888), S. comatularum (Haswell, 1882), S. stimpsonii (de Man, 1888); Palaemonidae: Palaemonella pottsi (Borradaile, 1915), Pontoniopsis comanthi (Borradaile, 1915), one brachyuran crab [Pilumnidae: Permanotus purpureus (Gordon, 1934)] and one squat lobster [Galatheidae: Allogalathea elegans (Adams White, 1848)] were identified. The caridean shrimps have associated with the crinoids Comaster multifidus (Müller, 1841), Phanogenia gracilis (Hartlaub, 1893), P. distincta (Carpenter, 1888), P. multibrachiata (Carpenter, 1888) and Stephanometra indica (Smith, 1876). The brachyuran crab was observed in association with the crinoid Phanogenia gracilis whereas the squat lobsters were associated with Stephanometra tenuipinna (Hartlaub, 1890) and S. indica. Except S. stimpsonii and P. purpureus, all other species were recorded for the first time from India. Here, we provide details on morphology, distribution, habitat, and hosts for all species. We recommend further exploration of the sub-shallow coral reef areas of Lakshadweep as there will be many species that certainly remain to be discovered.

Madangella koumacensis, a new species of palaemonid shrimps (Decapoda: Palaemonidae) from New Caledonia.

A second species of the recently established genus Madangella Frolová Duris is described from New Caledonia. Although the single available specimen lacks both second pereiopods, the new species distinctly differs from the only other representative of the genus, M. altirostris Frolová Duris, 2018 from Papua New Guinea, and can be easily distinguished from the latter by the more elongate and distally tapering rostrum, two subterminal ventral rostral teeth, the carpus of the first pereiopod being subequal to the merus length, and the sixth pleomere being short and stout, distinctly less than 2 times longer than deep. The examined specimen was confirmed as representative of a species separate from M. altirostris also by molecular comparisons of the 16S rRNA and COI mtDNA gene markers. The genus Madangella thus currently consists of two southwestern Pacific species.