Shiho’s Seahorse

Hippocampus sindonis (known in English as Dhiho’s or Shiho’s Seahorse) is a species of seahorse known only from the waters around Japan. The maximum recorded adult height is 8 cm. Total head length/snout length ratio is around 3.0 (2.8 to 3.3). The body includes 10 trunk rings and usually 37 tail rings (36 to 38). The dorsal fin is supported by 2 trunk rings and 1 tail ring. There are typically 12 dorsal fin rays (11 to 15) and 12 pectoral fin rays (12 to 14). There is a single prominent round-tipped cheek spine and a prominent double eye spine (front spine shorter than back one). (Lourie et al. 2004) Seahorses of this species have often been misidentified as H. coronatus (which, among other differences, has more tail rings) and H. mohnikei (which, among other differences, has 11 trunk rings, more tail rings, and double [low] cheek spines) (Lourie et al. 2004). Although little is known about the biology of this particular species, for seahorses in general, it is the male, rather than the female, that becomes pregnant. The female inserts her ovipositor into the male’s brood pouch, where she deposits her eggs, which the male fertilizes. The fertilized eggs then embed in the male’s pouch. The pouch acts like the womb of a female mammal, complete with a placental fluid that bathes the eggs, and provides nutrients and oxygen to the developing embryos while removing waste products. See Project Seahorse for more information about the fascinating biology of seahorses.

This species is distinguished in having the following characters: bony body; double gill openings; R 10 + 35-38 (holotype: 10 + 37); coronet moderately high; CoT 5; CHGO 26.8-41.0 % HL; CHMC 36.3-55.4 % HL; a very blunt or truncated spine on the dorsal fin base; absence of the wing-tip spine on dorsal fin base (Ref. 117115).

Male carries the eggs in a brood pouch (Ref. 205).

Reported to live in a wide range of habitats, from shallow high-energy algae reefs to soft bottom habitats (Ref. 117115). Length type refers to height (= TL - head length). Ovoviviparous (Ref. 205). The male carries the eggs in a brood pouch which is found under the tail (Ref. 205).

分布於西北太平洋海域，包括日本及臺灣等附近海域。臺灣分布於澎湖海域。

小型魚類，偶為潛水或網具捕獲，除學術研究及水族觀賞外，不具食用價值，但被做成中藥之藥材。

頭部與軀幹部幾成直角，無鱗，由一系列的骨環所組成；頂冠中等高，具分枝之皮瓣；體部各稜脊上之結節或稜棘亦具皮瓣。吻部稍短。骨環10+ 34-38；背鰭鰭條數11-15；胸鰭鰭條數12-14。體呈灰綠色；體側有時雜有斑駁或斑點。

主要棲息於具海藻床的礁石區，棲息深度可達20公尺，以小型浮游動物為食。

Shiho's seahorse or Sindo's Seahorse, painted seahorse (Hippocampus sindonis) is a species of fish in the family Syngnathidae. It is endemic to the Pacific coastal waters of Japan (from Wakayama pref. to Chiba pref.). This species reaches a length of ca. 8 cm. It was listed by the IUCN Red List as Vulnerable in 1996 and Data Deficient in 2003, but was later reclassified as Least Concern. The specific name honours Michitaro Sindo, who was originally from Yamaguchi and who was assistant curator of fishes at Stanford University.

Hippocampus sindonis, conventional and X-ray images of holotype