Big Spider, Big Genome: Chromosome-level genome of a North American tarantula (Aphonopelma marxi) and comparative genomics across 300 million years of spider evolution

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  Image Credit: WikiCommons Big Spider, Big Genome: Chromosome-level genome of a North American tarantula (Aphonopelma marxi) and comparative genomics across 300 million years of spider evolution Abstract The comparison of chromosome-level genomes allows biologists to investigate new axes of organismal evolution. Spiders comprise a significant proportion of known arachnid diversity, with many complex morphologies and unique natural histories, yet comparative genomics in spiders has been limited due to the number of available genomes. We present a de novo chromosomal reference genome of a mature male tarantula, Aphonopelma marxi, and comparatively examine spider genome evolution across the Order Araneae. Using PacBio HiFi and Hi-C sequencing, the final 6.5 Gb assembly consists of 17 autosomes, 1 X chromosome, and 127 unplaced scaffolds, with an N50 of 370 Mb and Arachnida (odb10; 2934 genes) BUSCO of 96.7%. By comparing 20 additional spider genomes from 15 families, we find mygalomo...

Toxic myocarditis following scorpion sting in a child: a case report and pediatric management approach

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Toxic myocarditis following scorpion sting in a child: a case report and pediatric management approach

Case presentation

A 3.5-year-old girl with no prior medical history was brought to the emergency department of a hospital in Birjand, Iran, at 23:50 by ambulance following a scorpion sting by a Hemiscorpius lepturus scorpion (locally known as “Gadim”). The sting occurred on the dorsal surface of her right upper limb. The patient presented with decreased levels of consciousness, hypotension, and anaphylactic shock. She complained of severe pain at the sting site and had experienced one episode of non-projectile, bilious, and non-bloody vomiting.

At the sting site, which appeared as a visible dot adjacent to a vein, erythema, edema, and mild tenderness were observed. Neurovascular examination of the affected hand was reported as normal. Neurologically, the patient was neither conscious nor oriented, with closed eyes, no response to verbal stimuli, and only localization to painful stimuli. The attending nurse documented an initial Glasgow Coma Scale (GCS) score of 10. Spontaneous and normal breathing was noted, and the pupils were bilaterally equal and reactive to light.


The patient was promptly placed under cardiopulmonary monitoring. Upon admission, her vital signs were as follows: respiratory rate (RR) of 30 breaths/min, heart rate (HR) of 150 beats/min, temperature (T) of 34.7 °C, oxygen saturation (SpO2) of 89%, and blood pressure (BP) of 70/42 mmHg. An emergency medicine specialist evaluated the patient, who was instructed to remain NPO, and an intravenous line was established. At the time of admission, she received two intramuscular doses of epinephrine (0.1 mg/kg, 1:1000), and 5 mg of intravenous chlorpheniramine (equivalent to 0.5 cc from the 10 mg/ml ampoule available in the Iranian pharmacopeia), and three vials of scorpion antivenom, along with intravenous normal saline (approximately 1 L over one hour) as part of fluid resuscitation to correct severe hypotension (BP 70/42 mmHg) and anaphylactic shock. Initial laboratory tests, including CBC, Diff, BUN, Cr, Bs, Na, K, Mg, Troponin I, Creatine Phosphokinase (CPK), N-terminal pro–B-type natriuretic peptide (NT-proBNP), and liver enzymes, were performed and sent for analysis. Based on clinical and paraclinical findings, no evidence of hemolysis or rhabdomyolysis was observed throughout the hospital stay. Chest X-ray (CXR) performed as part of the diagnostic evaluation, showing normal results (Fig. 1).

Akbari, A., Niksefat, F., Mirshahi, A. et al. Toxic myocarditis following scorpion sting in a child: a case report and pediatric management approach. BMC Pediatr 25, 900 (2025). https://doi.org/10.1186/s12887-025-06266-4