New data about the reproductive cycle of<i>Congeria kusceri</i>Bole, 1962 (Bivalves: Dreissenidae) from the pit ‘Jama u Predolcu’ (Croatia)

Rađa, Biljana; Rađa, Tonći

doi:10.1080/11250003.2011.581251

Cited by 2 publications

(5 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…On collection day T2, the water temperature was 17.2 • C and the dissolved oxygen was 6.6 mg/L. Both parameters, measured using a portable multimeter (a X-matePro MX300, Mettler Toledo, Columbus, OH, USA), were in line with the average values reported at the same periods by previous studies [11,13,20]. According to water level measurements conducted as part of this study, a drop in water level of approximately 42 cm was observed at T2, compared with T1.…”

Section: Sample Collection and Rna Extractionsupporting

confidence: 82%

“…During the summer, the water temperature always exceeds 15 • C, reaching peaks as high as 19 • C, as opposed to the winter minima, which may even occasionally drop to about 12 • C. In parallel, water alkalinity displays similar sudden changes, sensibly decreasing during the summer season to values below 200 mg CaCO 3 /L, compared with the higher levels usually observed during colder months [11,20]. Although variations of other chemico-physical parameters have been previously documented to occur throughout the year at the Jama u Predolcu, their effects on the biology of C. kusceri are still unknown [13]. Water levels also undergo significant changes, even though these variations are far less predictable and subjected to short-term fluctuations as they are strictly dependent on rainfall occurring in the area [20].…”

Section: A General Overview Of Gene Expression Changes Occurring From...mentioning

confidence: 93%

“…Annual reproductive cycles are strictly regulated by the water influx from the surface, which in turn critically depends on rain precipitation, determining marked seasonal fluctuations of both water levels (higher in winter, lower in summer) and temperature (lower in winter, higher in summer) [12]. Although other physical and chemical parameters also undergo significant variations throughout the year in the subterranean environment of the Dinaric Karst, their effects (if any) and the biology of Congeria are still poorly understood [13].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Variation of Gene Expression in the Endemic Dinaric Karst Cave-Dwelling Bivalve Mollusk Congeria kusceri during the Summer Season

Scapolatiello,

Manfrin,

Greco

et al. 2023

Diversity

View full text Add to dashboard Cite

The cave systems of the Neretva River basin in the Dinaric Karst are home to Congeria kusceri, one of the very few known examples of stygobiotic bivalve mollusks, which displays several unique life history traits and adaptations that allowed its adaptation to the subterranean environment. This endemic species is undergoing rapid decline, most likely linked with habitat degradation, which might seriously threaten its survival in the next few decades. Unfortunately, the urgent need for effective conservation efforts is hampered by the lack of effective regulations aimed at preserving remnant populations as well as by our limited knowledge of the biology of this species. Although the precise factors underlying the disappearance of C. kusceri from its type locations are not entirely clear, the alteration of seasonal changes in water temperatures and alkalinity is most likely involved, as these are the main drivers of shell growth, spawning, and the onset and progression of the new gametogenic cycle. While these aspects have so far only been studied using morphological and physiological observations, future conservation efforts would certainly benefit from an integrated multidisciplinary approach. Here, using RNA-sequencing, we provide an overview of the modulation of gene expression recorded in five key tissues (the mantle, gonads, gills, adductor muscle, and digestive gland) between early June and late September. We highlight the presence of markedly tissue-specific responses, with the most dramatic changes affecting the gonads, mantle, and gills. We further identified a drastic switch in the use of energy budgets between the two periods, with evidence of ongoing shell growth and high metabolic activity in the mantle and gills at the early time point, followed by a massive redirection of all available energy to the gonads for the generation of new gamete primordia in early autumn.

show abstract

Section: Sample Collection and Rna Extractionsupporting

confidence: 82%

Section: A General Overview Of Gene Expression Changes Occurring From...mentioning

confidence: 93%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Variation of Gene Expression in the Endemic Dinaric Karst Cave-Dwelling Bivalve Mollusk Congeria kusceri during the Summer Season

Scapolatiello,

Manfrin,

Greco

et al. 2023

Diversity

View full text Add to dashboard Cite

show abstract

“…No eggs or larvae of C. kusceri were ever collected in plankton‐net trawls of the Jama u Predolcu pit, between January and December 2009 (Rađa & Rađa, ). Moreover, the same authors found no evidence of larval brooding in the ctenidia of C. kusceri , despite the circumstantial evidence for this (enlarged hypobranchial gland cells and unfertilized eggs held in one ctenidium of one female) provided by Morton et al .…”

Section: Resultsmentioning

confidence: 99%

“…In the absence of individuals actually brooding fertilized eggs, however, this was still conjecture. Subsequently, Rađa & Rađa () disputed this claim and, despite not finding free‐swimming bivalve larvae in their year‐long collection of plankton samples, concluded that C. kusceri was not a brooding species.…”

Section: Introductionmentioning

confidence: 99%

Life-history strategy, with ctenidial and pallial larval brooding, of the troglodytic ‘living fossil’Congeria kusceri(Bivalvia: Dreissenidae) from the subterranean Dinaric Alpine karst of Croatia

Morton

Puljas

2012

Biol J Linn Soc Lond

View full text Add to dashboard Cite

Among freshwater bivalves, the brooding of embryos and larvae within the maternal ctenidia is well known. Exceptions to this generalization are the non‐brooding freshwater and estuarine species of Dreissena and Mytilopsis, respectively. It was reported that the freshwater troglodytic cousin, Congeria kusceri Bole, 1962, of these dreissenids does not brood either. It is herein demonstrated that C. kusceri undergoes one reproductive cycle each year. Sexes are separate, with an early male and later female bias. A small percentage (2.14%) of individuals is hermaphroditic. The gonads mature over summer from May to November. Spawning commences in September, when females release mature oocytes into their ctenidia and inhale sperm from mature males. Here the oocytes are fertilized, and develop within interfilamentary marsupia. Ctenidial tissues glandularize, and may provide a source of maternal nutrition for the embryos. At the late prodissoconch‐1 or prodissoconch‐2 stage (PR2, ~220 μm), larvae are released into the infrabranchial chamber via a birth channel along the outer edge of the ventral marginal food groove of both inner demibranchs. Here, they are brooded further in mantle pouches located beneath the inhalant siphon. Subsequently, after the PR2 stage (nepioconch/dissoconch), they are released from the inhalant siphon and assume an independent life as crawling juveniles. Such juveniles may be found amongst clusters of adults. Not only is C. kusceri unique amongst the Dreissenidae in possessing the capacity to brood internally fertilized ova, but it is also exceptional amongst the Bivalvia in possessing the described methods of brooding and birth. Explanations for both lie in its troglodytic lifestyle, decadal length longevity and habitat: that of byssal attachment to the hard surfaces of underground freshwater rivers, caves, pits, and sinkholes in the Tethyan arc of the Dinaric karst. Internal fertilization of a few large yolky eggs, lecithotrophic larvae, ctenidial brooding, and secondary pallial parental care represent relatively recent, Late Miocene, evolutionary adaptations from a Tethyan lentic ancestor.

show abstract

New data about the reproductive cycle ofCongeria kusceriBole, 1962 (Bivalves: Dreissenidae) from the pit ‘Jama u Predolcu’ (Croatia)

Cited by 2 publications

References 14 publications

Variation of Gene Expression in the Endemic Dinaric Karst Cave-Dwelling Bivalve Mollusk Congeria kusceri during the Summer Season

Variation of Gene Expression in the Endemic Dinaric Karst Cave-Dwelling Bivalve Mollusk Congeria kusceri during the Summer Season

Life-history strategy, with ctenidial and pallial larval brooding, of the troglodytic ‘living fossil’Congeria kusceri(Bivalvia: Dreissenidae) from the subterranean Dinaric Alpine karst of Croatia

Contact Info

Product

Resources

About