The Crying Izak or Tropical Izak (Holohalaelurus melanostigma) is a very rare catshark belonging to the family Scyliorhinidae. It is found in the western Indian Ocean off Mozambique and Tanzania, at depths of between 1,991-2,159 feet. Male specimens have been measured at 38 cm/1.2 feet. The Crying Izak has distinct marks that look like tears running down their snout from their eyes.
Family: Scyliorhinidae – Catsharks
Genus: Holohalaelurus
Species: melanostigma
Phylum– Chordata
Class– Chondrichthyles
Common Name– Ground Sharks
Family– Scyliorhinidae
Common Name– Catsharks
Genus– Holohalaelurus
Species– melanostigma
Status: IUCN Red List DATA DEFICIENT
Average Size and Length: Mature males have been measured at 38 cm/1.2 feet. The length of females is unknown. The maximum length is more than likely greater than 38 cm/1.2 feet.
Current Rare Mythical Sightings: Described by Norman in 1939, the name is most likely derived from the Greek word ‘melano‘ for black and ‘stgma‘ for mark or spot, referring to the dark colored spots on the dorsal surface of the body.
Teeth and Jaw: The buccal papillae in the mouth is inconspicuous. There are relatively high tooth counts, 57 total upper teeth in the holotype (54, 59, mean 57.8 for the paratypes), 50 total lower teeth in the holotype (49, 63, mean 55.8 for the paratypes).
Head: The head is broad. The snout is short and the mouth is long.
Denticles: There are slightly enlarged rough dermal denticles on the midline or middle of the back from a point level to the pectoral origin on the dorsal midline to the first dorsal origin. There are no enlarged denticles on the dorsal surface of the pectoral fin.
Tail: The tail is slender.
Demographic, Distribution, Habitat, Environment and Range: The Crying Izak or Tropical Izak can be found in the western Indian Ocean in Mozambique and Tanzania, including Zanzibar and possibly even Kenya (4°S – 5°S). They can be found on the continental slope between 1,991-2,159 feet and are considered tropical bathydemersal.
Aesthetic Identification: The Crying Izak or Tropical Izak has scattered tiny black dots beneath the head. It is grey-brown in color dorsally, and lighter ventrally. The upper surface has many large dark brown spots, some that are fused to form reticulations, horizontal stripes and blotches. There are distinct horizontal marks that look like tear marks on the snout in front of the eyes. There are dark lines and a C shaped mark on the bases and webs of the dorsal fins. The dorsal fins are short and angular. There are no club-shaped papillae on the distal tip of the clasper.
Biology and Reproduction: The vertebral count is moderate to high, 121 total in the holotype, 115 and 119 (mean 116.8) for the paratypes.
Behavioral Traits, Sensing and Intelligence: Unknown.
Crying Izak or Tropical Izak Future and Conservation: There is currently not enough data to evaluate. They are extremely rare and only known from a few museum specimens.
Crying Izak or Tropical Izak Recorded Attacks on Humans: Not a threat to humans.