裸頭龍鰧屬

裸頭龍鰧屬
科學分類
界：	動物界 Animalia
門：	脊索動物門 Chordata
綱：	輻鰭魚綱 Actinopteri
目：	鱸形目 Perciformes
科：	龍鰧科 Bathydraconidae
亞科：	淵龍鰧亞科 Bathydraconinae
屬：	裸頭龍鰧屬 Akarotaxis H. H. DeWitt & Hureau, 1980

裸頭龍鰧屬（學名：Akarotaxis）是輻鰭魚綱龍鰧科之下一個海魚的屬，其物種皆棲息於南極洲位於南冰洋的大陸架。過往本屬只有裸頭龍鰧一個物種；後來美國弗吉尼亞海洋科學研究所（VIMS）威廉與瑪麗學院的科學家在南極洲西側半島冰冷的海域中，發現了本屬的另一全新物種「帶狀龍鰧」（Akarotaxis gouldae）。

分類學

裸頭龍鰧屬的物種最早於1980年由美國魚類學家 休·漢密爾頓·德威特（Hugh Hamilton DeWitt）和法國魚類學家讓-克洛德·胡羅（Jean-Claude Hureau）的研究首度描述，當時本屬只有裸頭龍鰧（Akarotaxis nudiceps）一個物種。這個物種的描述早在1916年，由英國出生的澳大利亞動物學家埃德加·拉文斯伍德·韋特描述為Bathydraco nudiceps，模式產地位於沙克爾頓冰架對出的瑪麗皇后地。 The type was collected by the Australasian Antarctic Expedition. The generic name compounds akaro meaning "short" or "small" with "taxis" which means "line" or "row", a reference to the short upper 體側線, which comprises lees than 10 tubular scales. The 種本名 nudiceps means "naked head", thought to be an allusion to the absence of scales on the head despite Waite not mentioning this trait.

Akarotaxis gouldae was described in August 2024, based off of specimens exclusively found in a 400 km stretch of coastline in the 南極半島, from 拉佩雷爾灣 in the north to 阿德萊德島 in the south. The describers refrain from citing this as strong evidence of distribution, as it may be an artifact of 偏差樣本. The specific name was coined in honor of the U.S. Antarctic Research and Supply Vessel Laurence M. Gould, and not the namesake of the vessel itself. A. gouldae was coined in the feminine form specifically to honor the ship, reflecting the practice of assigning ships female pronouns.

Description

Akarotaxis has a slender, body which is covered in 魚鱗 scales and has two lateral lines, the upper lateral line having only 3-9 tubed scales in its anterior section with its posterior part being made up of poredscales which also make up the middle lateral line. The upper rear margin of the operculum has a small hook. They are equipped with small conical teeth arranged in bands. The dorsal fin has 29-33 soft rays while the 魚鰭 has 25-28 soft rays. Specimens preserved in alcohol have a brown body with a darker head, a pale dorsal fin pale and the other fins being dusky. This species attains a maximum standard length of 13.0 cm（5.1英寸）.

Distribution, habitat and biology

Akarotaxis is found almost all around the Antarctic continent from west of the 阿德萊德島 to the 羅斯海 where it is a bathydemersal species found at depths between 371至915米（1,217至3,002英尺） on the outer 大陸架 and in deep troughs. It has the lowest known fecundity of the Antractic dragonfishes, laying only 2000 eggs per female. 產卵 takes place from mid to late summer.

Threats

A. gouldae exhibit extremely low 繁殖力. They also associate with the ocean surface. Ergo, the budding Antarctic krill fishery in the region may capture A. gouldae larvae as bycatch, and thus imperil the species.