短毛藻属Elachista隶属于褐藻门Phaeopyta索藻目Chordariales短毛藻科Elachistaceae, 由Duby (1830: 972)^[1]建立。其主要特征为藻体(孢子体)丛生或扩展; 基部由无色假膜组织组成, 呈垫状或半球状, 附着或部分深入其他海藻的组织中; 同化丝着生于假膜组织上, 在基部分枝, 可分为长同化丝和短侧丝(短同化丝), 侧丝多弯曲丛生; 基部生长, 色素体盘状, 多数; 单室囊和多室囊生于同化丝之间; 异型世代交替, 配子体为微小匍匐体。模式种为E. scutellata Duby 1830: 972, nom.illeg.[=E. scutullata (Smith)Areschoug]^{[1, 2]}。

本属在国际上已报道了65个分类单位, 目前可接受的物种23个^[2-6]。其中, 东亚报道了11个种(可接受的)^[7-13], 我国报道了短毛藻E. fucicola (Velley) Areschoug^{[8, 9, 11]}和纤细短毛藻E. tenuis Yamada^{[14, 15]}等2个种。

作者自1999~2003年对中国沿海多个地区进行了野外调查, 采集了一些该属的标本。结合我国过去的一些报道(文献)和样品, 经分类与鉴定研究, 发现我国短毛藻属新物种2个, 分别为长海短毛藻E. changhaiensis Luan et Ding sp.nov.和暗色短毛藻E. fusca Luan et Ding sp.nov.。本文对这2个种进行了较详细的描述, 其结果在一定程度上丰富了我国大型海洋褐藻的种类多样性。标本保存在中国科学院海洋研究所海洋生物标本馆(AST)。

1 材料与方法 1.1 实验材料

1999~2003年作者在我国沿海野外现场调查采集的标本及之前保存在中国科学院海洋研究所海洋生物标本馆(AST)的部分标本。

1.2 实验方法 1.2.1 外形特征比较

主要包括藻体颜色、基部情况、同化丝的类型、繁殖器官等特征。

1.2.2 显微制片

徒手切片或整体装片。

1.2.3 物种鉴定

通过分类特征的对比及相关数据的比较, 结合文献报道鉴定物种。

1.2.4 绘图

利用显微镜和解剖镜的自配描绘装置对物种特征进行手绘图。图型上墨利用Adobe Illustrator CS4和UGEE绘影G3数位板完成^[16-17]。

2 结果 2.1 长海短毛藻(新种)图 1

Elachista changhaiensis Luan et Ding sp.nov.

Thalli are yellow brown, semi-spherical, 0.3-0.4 cm in diameter, epiphytic on the surface of other macroalgae. The base of thallus is pseudomembranous structure, consisted of many colourless filaments, 1 150-1 250 µm long, with cells 75-200 µm long, 20-45 µm broad and L/B 1.7-8. The bases of some filaments insert into the host epidermis. The free long assimilating filaments and paraphyses (short assimilating filaments) are born on the outside edge of pseudomembranous structure. Long assimilating filaments are 3 700-4 300 µm long, consisted of 150-185 cells, and taper from lower part to upper part. The cells are 22-50 µm, 17-40 µm and 15-22 µm long, 16-22 µm, 9-15 µm and 7-10 µm broad, L/B 1.3-2.6, 1.9-3.3 and1.5-3 at the lower, middle and upper part, respectively. Short assimilating filaments are 200-350 µm long, consisted of 11-24 cells with 18-29 µm and 12-25 µm long, 5.5-8 µm and 6-8 µm broad, L/B 2.3-4 and 1.7-3.3 at lower and upper part, respectively. Chloroplasts are small sphere-shape. Hairs are unseen.

The plurangia are born on the outside cells of the pseudomembranous structure, unbranched or branched at the basal part, linear, dense, monostichous, 95-150 µm long, 5-6 µm broad, usually consisted of 23-38 chambers. The unangia are born on the pseudomembranous structure at the same plants as those of the plurangia, petiolate, elongated saccate, 98-150 µm long, 23-26 µm broad.

Habits: The plants are epiphytic on the blades of Sargassum confusum at the low tide zone, mixed with Protectocarpus speciosus. It is endemic to Haiyang island, Changhaixian, Liaoning, China.

Geographic distribution: the Yellow Sea.

Holotype: AST039025, collected by Luan Rixiao at Mar. 17, 2003.

Type locality: Changhai, Liaoning, China.

特征描述:藻体黄褐色, 半球形, 直径3~4 mm, 附着于其他海藻上。基部为假膜体, 由很多无色丝状体组成, 长1 150~1 250 µm, 细胞长75~200 µm, 宽20~45 µm, 长为宽的1.7~8倍; 丝体基部有少量伸入宿主表皮细胞间。在假膜体外缘生有游离的长同化丝和侧丝(短同化丝)。长同化丝长3 700~4 300 µm, 由150~185个细胞组成, 由下向上渐细; 下部细胞长22~50 µm, 宽16~22 µm, 长为宽的1.3~2.6倍; 中部细胞长17~40 µm, 宽9~15 µm, 长为宽的1.9~3.3倍; 上部细胞长15~22 µm, 宽7~10 µm, 长为宽的1.5~3倍。短同化丝长200~350 µm, 由11~24个细胞组成; 下部细胞长18~29 µm, 宽5.5~8 µm, 长为宽的2.3~4倍; 上部细胞长12~25 µm, 宽6~8 µm, 长为宽的1.7~3.3倍。色素体小球形。无毛。

多室囊着生于假膜丝体外部的细胞上, 不分枝或在基部有分枝, 线状, 密集, 单列, 长95~150 µm, 宽5~6 µm, 由23~38个小室组成。单室囊与多室囊同体, 着生于假膜体的细胞上, 具有一柄细胞, 长囊状, 长98~150 µm, 宽23~26 µm。

习性和产地:在低潮线下附着于Sargassum confusum的叶面上, 和Protectocarpus speciosus混生。产于辽宁长海县海洋岛。

地理分布:黄海。

模式标本:于2003年3月17日栾日孝采自辽宁省长海县, 模式标本号为AST039025。

2.2 暗色短毛藻(新种)图 2

Elachista fusca Luan et Ding sp. nov.

Thalli are dark brown, hemisphere, with 1-4mm in diameter. The base is consisted of parenchymal cells to the cushion-like pseudomembranous structure, with a part stretching into the host organization. The cells of the cushion-like part are colourless, irregularly cylindrical, 20-175 µm long, 9-30 µm broad and L/B 1.7-9. The free assimilating filaments are born on the outside cells of the cushion-like pseudomembranous structure and consisted of long assimilating filaments and paraphyses (short assimilating filaments). The long assimilating filaments are 1.l-4 mm long, usually consisted of 135-216 cells with 17-40 µm long, 8-14 µm broad and L/B 1.4-3.3. The short assimilating filaments are born on the base of the the long assimilating filaments, 0.13-0.33 mm long, and consisted of 5-13 cells with 20-35 µm long, 5-7.5 µm broad and L/B 3-6. Hairs are unseen.

The plurangia and unangia are born on the same plants. The plurangia are linear, monostichous, born on the base of the short assimilating filaments or the outside cells of the pseudomembranous structure, unbranched or few branched, 75-150 µm long, 5-6 µm broad, usually consisted of 27-39 chambers. The unangia are born on the base of the assimilating filaments or the outside cells of the pseudomembranous structure, sessile, elongated saccate, 100-120 µm long, 25-35 µm broad.

Habits: The plants are epiphytic on sargassum confusum at the middle intertidal zone, intermixed with Halothrix gracilis. It is endemic to Dalian, Liaoning Province, China.

Geographic distribution: the Bohai Bay, China.

Holotype: AST9990072, collected by Luan Rixiao at Mar. 17, 1999.

Type locality: Dalian, China.

特征描述:藻体暗褐色, 半球形, 直径0.8~4 mm。基部由薄壁细胞组成垫状假膜体, 少部分伸入宿主组织间。基部垫状的假膜组织细胞无色, 多呈不规则圆柱形, 细胞长20~175 µm, 宽9~30 µm, 长为宽的1.7~9倍。垫部外为游离的同化丝, 同化丝可分成长同化丝和侧丝(短同化丝), 着生于假膜组织细胞上。长同化丝长1.l~4 mm, 通常由135~216个细胞组成; 细胞长17~40 µm, 宽8~14 µm, 长为宽的1.3~3.3倍。短同化丝着生于长同化丝的基部, 长0.13~0.33 mm, 由5~13个细胞组成; 细胞长20~35 µm, 宽5~7.5 µm, 长为宽的3~6倍。无毛。

单室囊和多室囊同体。多室囊线状, 单列, 着生于短同化丝基部或假膜组织外部细胞上, 多不分枝或少数分枝, 长75~150 µm, 宽5~6 µm, 通常由27~39个小室组成。单室囊着生于同化丝基部或假膜组织外部细胞上, 无柄, 长囊状, 长100~120 µm, 宽25~35 µm。

习性和产地:在中潮带附着于Sargassum confusum体上, 和Halothrix gracilis等混生。产于辽宁大连。

地理分布:中国渤海。

模式标本:于1999年3月17日栾日孝采自中国大连, 模式标本号为AST9990072。

3 讨论

本文报道了2个新种。其中长海短毛藻E. changhaiensis Luan et Ding sp.nov.与E. tenuis Yamada^{[10, 14-15]}相似, 暗色短毛藻E. fusca Luan et Ding sp.nov.与E. tenuis Yamada和E. orbicularis (Ohta)Skinner^{[10, 18]}相似, 两个新种之间也有相似之处。比较结果见表 1。