台灣海域產鼠尾鱈科魚類之系統分類研究

Abstract

鼠尾鱈(Family Macrouridae)為深海底棲性魚類，多數生活在溫帶及熱帶海域水深200?6000公尺之間，全世界共4亞科32屬約300種(Nelson,1994)，1995至1999年間則又陸續發表26種。目前台灣海域水深200?800公尺之間共採獲有2亞科11屬40種，其中包括腔吻鱈屬(Caelorinchus)的3種新種窄吻腔吻鱈(Caelorinchus leptorhinus)、鞍斑腔吻鱈(C.ephippins)與長絲腔吻鱈(C.logispinosus)，及台灣地區1個新紀錄亞科、6個新記錄屬、19個新記錄種。分別為新紀錄底尾鱈亞科(Bathygadinae)之鞭鼠鱈(Gadomus colletti)、孔頭底尾鱈(Bathygadus antrodes)、日本底尾鱈(B.nipponicus)、鬚底尾鱈(B.garretti)；以及鼠尾鱈亞科(Macrourinae)之細身膜鱈(Hymenogadus gracilis)、刺吻膜首鱈(Hymenocephalus lethonenus)、獅鼻奈氏鱈(Nezumia condylura)、偽鯨尾鱈(Pseudoctenurous septifer)、日本舟尾鱈(Kumba japonica)、長鬚凹腹鱈(Ventrifossa longibarbata)、大鰭凹腹鱈(V.macroptera)、扇鰭凹腹鱈(V.rhipidodorsalis)、西海凹腹鱈(V.saikaiensis)、魔燈凹腹鱈(V. lucifer)、歧異凹腹鱈(V.divergens)、箭齒凹腹鱈(V.atherodon)、東海腔吻鱈(Caelorinchus productus)、長管腔吻鱈(C.longissimus)及擬星腔吻鱈(C.asteroides)等。 由於深海魚類採集技術較為困難，且採獲之標本多半殘破不堪、難以正確鑑別屬種、所以過去台灣的鼠尾鱈科魚類研究較為欠缺，另外舊有的記錄中大部份種類亦無標本可供查考，因此本研究為過去文獻中缺乏標本的種類，重新提供登錄的標本證據，亦修訂了早期報告中誤鑑、同種異名及位階安置不當等問題。文中除整理出鼠尾鱈科魚類各亞科、屬及種檢索表、同種異名錄、鑑別特徵、體型、分佈，相似種間之比較和備註等資料外，並附以台灣產 40種鼠尾鱈的彩色標本照以供相關研究人員分類鑑定之參考。 在類緣關係方面，利用16個測量形質、8個計數形質及67個其他一般外部形質等91個特徵，以表型及支序分析方法推斷其類緣關係。其結果在鼠尾鱈亞目中鼠尾鱈科，包含各亞科及若干屬與亞屬間的關係與過去所作之研究結果並不一致。表型聚類分析與支序分析結果顯示底尾鱈亞科、鼠尾鱈亞科、Caelorinchus屬與Hymenogadus-Hymenocephalus group各為4組相當獨立的單系群。支序分析結果顯示底尾鱈亞科為最原始的一群而Caelorinchus屬為最特化的一群。Ventrifossa屬在表型分析中聚為一單系群，但在支序分析中各種間關係混淆，Hymenogalus-Hymencephalus group在表型分析中之差異達屬級水準，但在支序分析中未達屬級水準；Caelorinchus屬4亞屬間關係在2種分析結果均混淆，因此本研究不贊同將Caelorinchus屬區分成4亞屬，Hymenogadus屬與Hymenocephalus屬在表型分析與支序分析有不同的結果，因此兩者間的差異是否達到屬級水準，則有待更深入的探究。Kumba屬、Pseudoctenurous屬、Malacocephalus屬在表型分析中類緣關係較接近Ventrifossa屬；在支序分析中Pseudoctenurous屬興Malacocephalus屬較接近，Kumba屬關係混淆。Nezumia屬與Coryphaenoides屬在表型分析中為關係接近的2群，但在支序分析中關係混淆。 在地理分佈方面，台灣周邊海域以東北海域大溪之魚類相最為豐富，目前的資料亦顯示台灣東北部及西南部的種類組成有明顯差異；在豐度方面，鼠尾鱈科魚類中則以Caelorinchus kishnouyei、C.multispinulosus、C. formosanus和Ventrifossa rhipidodorsalis的分佈最廣，數量也最多。在印度太平洋區所有的233種鼠尾鱈科魚類中則以台灣、中國、日本三者的鼠尾鱈魚種組成最為接近，其次為菲律賓及東印度群島，66％種類目前只發現在單一區域，6％的種類分佈超過3個區域為本科魚類中少見之廣泛種，此顯示鼠尾鰭的稀有種比例高，其原因可能是採樣仍不足，或多數鼠尾鱈之地理分佈範圍並不廣泛之故。

The grenadiers (Family: Macrouridae) is one of the major group of benthopelagic fishes. Grenadiers occupy all oceans, except the high Arctic, and almost all basins with deep oceanic connections; none normally occur in depths shallower than found at abyssal depths. One species to more than 6000m, most species are found between 200m and 2000m (Iwamoto, 1990). At present, Grenadiers are approximately divided into 4 subfamilies, 38 genera and 327 species in the world. According to “Fishes of Taiwan” (Shen et al, 1993), there were 1 subfamily, 5 genera and 19 species occurred in Taiwan. The present study attempted to review this group of fish by re-examining previous deposited specimens and re-collecting new specimens from deep sea bottom trawler fisheries from 300-800 meters in north-eastern and south-western waters near Tashi, Nanfanao and Tungkang. Our preliminary study results obtained a total number of 2 subfamilies, 11 genera and 40 species in which 19 species are new records and 3 are new species .They include three new species of Caelorinchus leptorhinus ,C.ephippins and C.logispinosus, and new records of 19 species: Gadomus coletti, Bathygadus antrodes, B.nipponicus, B.garretti, Hymenogadus gracilis, Hymenocephalus lethonenus, Nezumia condylura, Pseudoctenurous septifer, Kumba japonica, Ventrifossa longibarbata , V.macroptera, V.rhipidodorsalis V.saikaiensis, V.Lucfer, V.divergens, V.atherodon, C.productus, C. longissimus and C.asteroids. Due to the difficulty and the divergence of character's identification, the classification of this group of fish have many synonymous, misidentification and different classification system problems. The diagnostic key and the specimen color photos of each species are provided. Additionally, the phylogenetic relationship of these 11 genera and 40 species were constructed using both phenetic and cladistic methods. Using 91 morphological characters to construct the phylogenetic relationships by phenetic (NTSYS) and cladistic (Henning 86).In conclusion:the subfamily Bathygadinae,Macrouridae, genus Caelorinchus and Hymenogadus-Hymenocephaius group are surely four monophyletic groups.The cladistic analysis shows Bathygadinae is more primitive than other taxa and Caelorinchus is the most specialize group for Macrouridae. Macrourinae and Bathygadinae are sister group. The relationship for Ventrifossa is a monophyletic group; Hymenogadus and Hymenocephalus reach the genus level; Nezumia and Coryphaenoides are sister group; Kumba, Pseudoctenurous, Malacocephalus and Ventrifossa are very close in phenetic analysis. The phylogeny of Ventrifossa is not a monophyletic group; Hymenogadus and Hymenocephalus not reach the genus level; Kumba, Pseudoctenurous, Malacocephalus, Nezumia and Coryphaenoides are still unresolved in cladistic analysis. The difference for Oxymacrurus, Oxygadus, Paramacrurus and Quincunica of Caelorinchus are not reach the subgenus level in phenetic and cladistic analysis. So in the present study that the rank of subgenus for Caelorinchus differ from the generally-acknowledged system. The thesis also analysis the distribution and abundance data of macrounds from the waters around Taiwan. Tashi has the highest fish fauna compare with the Tungkang and Nanfanao. Caelorinchus formorsanus, C.kishnouyei, C.multispinulosus and Ventrfossa rhipidodorsalis are the dominant species regarding to the total catch. As to the zoogeographical distribution, the species composition of grenadiers between north and south Taiwan are quite different. This result is quite consistent with the pattern obtained from coral reef and estuarine fishes. It may imply that the different fish fauna between northern and southern Taiwan can extend to the fishes which inhabit in deep waters. The thesis review the macrourids fauna of 9 areas of Indo-Pacific region. Taiwanese macrourids fauna are most similar to that of Japan and China. The global geographical distribution of macrourid species should be affected by the factors of degree of latitude, water temperature, ocean currents, land barrier, geographical distance, depth and substrata.