Description of a Wood-Dwelling Sipunculan, Phascolosoma turnerae, New Species
Description of a Wood-Dwelling Sipunculan, Phascolosoma turnerae, New Species
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木栖 Sipunculan、Phascolosoma Turnerae、新物种的描述
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发表时间：
1985
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通讯作者：
M. E. Rice
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作者：
M. E. Rice
•Phascolosoma tiirnerae是Sipuncula门的一个新种，它是在基韦斯特以南的佛罗里达海峡1135 - 1184米深处和阿拉巴马州莫比尔以南的墨西哥湾北部366-412米深处采集的104个标本中描述的。这些标本被发现与淹没的木头有关，占据了木头的洞穴。在佛罗里达海峡的样本中，水蚤管已经穿透了木材，并且经常缠绕在水蚤的身体上。图1-4材料检查。•2个标本，2个具有延伸的触角（20个解剖，1个准备用于扫描电子显微镜）。迈阿密大学罗森斯蒂尔海洋与大气科学学院Gerda Station 448；1964年12月1日；620 - 647英寻;21 'w 23°54’,82°。19个标本（5个解剖标本）密西西比州帕斯卡古拉美国鱼类和野生动物管理局商业渔业局俄勒冈站3753；1962年8月28日；200 - 225英寻;29°13.5镑,87°58.5 'w。全型：USNM 96687（解剖），来自Gerda Station 448。图a， b, c, d.异型：来自Gerda站448的USNM 96688（图5，解剖），96689（图5），96690（图5）。诊断。•InXvoverX的长度几乎等于主干；在最内向的前部约有50排紧密相对的钩，后面是一排排间隔更宽的钩；大多数后排背面不完整。触须冠背向嘴部，在与身体大小的比例上比通常的相结肠瘤大；X'X-ll数字化的触手。特别大的乳突状乳头具突出的顶端突起；丘疹最大和最多数在内向和后干的基部。乳头表面覆盖小的颗粒状血小板，也散布在非乳头体表面。纵体壁肌肉组织分离成吻合束。四牵开肌，背部在躯干的中间三分之一，腹侧在后三分之一；牵开肌在大部分长度上分开。梭形肌附著于躯干末端后方和肛门上方的前方。一块固定肌，将下食道连接到躯干中部至腹侧神经索左侧的体壁。肠线圈大约有15个单线圈。血管简单收缩。肾轴几乎整个长度附着于体壁；肾孔在肛门的大约水平。钩尖锐弯曲的远端具清晰的条纹接近凸表面；相对狭窄的在基部具基部的小根在凹侧。描述。•Gerda收集的标本平均长度为6.7毫米（n = 80）， M/V Oregon收集的标本平均长度为12.8毫米（n = 14）。两组的范围分别为3.5 ~ 11.4 mm和7.417.3 mm。在两个来自Gerda收藏的标本中，内向者和触须完全伸展；在其他情况下，内向者则处于不同的牵引状态。其中一个扩展标本的总长度为12毫米（Holotype USNM 96687），另一个（parotype USNM 96689）的总长度为17毫米。在前者中，内向者与主干的比例为1:1.4，后者为1:1.1。在这两个标本中，相对粗壮的内向者大约是躯干最大宽度的一半。内向者的宽度大约是长度的三分之一；躯干的比例是一样的。短而粗的数字化触须在全型中有14个，在准型中有22个。它们在嘴的背面排成一个圆圈，在背中线处被一个心形的颈器官打断。这些保存下来的标本的身体颜色通常是浅灰黄色，后躯干和前躯干比中部略深。前向内向型鱼钩颜色深，外表呈褐色。在整体型的扩展内向者身上有70排钩。前25行是完全形成的，而后面的那些可能是不完整的背（特别是在25至45行）。在前52排挂钩紧密相对之后，各个挂钩被更广泛地分开。在第70行之后出现了分散的钩子，但不再有明显的排列。前5 ~ 6行鱼钩呈淡单宁黄色，其余为深褐色。最前面的5排比后面的5排小，除了最后面的5排越来越小。钩子的形式很简单（图1、图1、图2）。末端有明显的弯曲，在靠近凸曲率的钩内，从基部到顶端有一条清晰的条纹，沿顶端宽度逐渐减小。钩最好在第6行到第50行之间。对USNM 96690型钩从第5行到第19行的测量显示，平均基宽为0,044毫米，平均高度为0.051毫米。每个钩子上大约有10个基突。内向的乳头在钩排之间有规律的间隔出现（图2）。体壁相当薄，特别是在躯干中部区域，纵肌带透过被膜可见。这个物种最显著的特征是在前和后干的乳头的大小和形状（图，lb, c, d; 3）。在这些区域，乳突数量多，集中，呈乳状，每一个中央突起有一个孔。最常见的是宽度和高度大致相等，尽管其中任何一个都可能稍微超过另一个。在Gerda收集的标本中，最大的乳突的宽度和高度为0.16 x 0.16毫米，其躯干长度从7毫米到10毫米不等。M/V Oregon收集的稍大一些的标本的乳突，其躯干长度从17到18毫米不等，显示出最大宽度和高度为0.24 x 0.30毫米。在收缩的标本中，乳突的基部可以收缩，形成一根茎。在中干区域的乳突很少，分散和非常扁平。其中最大的与最大的前后乳头直径相同，但它们很少或没有隆起。乳头被膜内嵌有小的、分离良好的血小板，颜色从无色到浅棕色不等。类似的血小板分布在皮肤各处，尽管它们更集中在乳头上。乳突中央突起常呈褐色。纵向肌肉组织束经历了相当大的分裂和56华盛顿生物学会学报第98卷，第1号57图2-3，phascolsoma iurnerae：电子显微照片，规模= 20 /im)；(扫描电镜图，刻度= 2,（左）前内向者的一排排钩(扫描3，（右）前干和后内向者的乳头状突起
•Phascolosoma tiirnerae, a new species of the phylum Sipuncula, is described from 104 specimens collected at depths of 1,135-1,184 meters in the Straits of Florida, south of Key West and from 366-412 meters in the northern Gulf of Mexico, south of Mobile, Alabama. The specimens were found in association with submerged wood, occupying burrows in the wood. In the sample from the Straits of Florida, pogonophoran tubes had penetrated the wood and were frequently entwined around the bodies of the sipunculans. Phascolosoma turnerae, new species Fig. 1-4 Material examined. •is specimens, 2 with extended tentacles (20 dissected, 1 prepared for scanning electron microscopy). Gerda Station 448, Rosenstiel School of Marine and Atmospheric Science, University of Miami; 1 Dec 1964; 620-647 fathoms; 23°54'N, 82°21'W. 19 specimens (5 dissected) M/V Oregon Station 3753, Bureau of Commercial Fisheries, United States Fish and Wildlife Service, Pascagoula, Mississippi; 28 Aug 1962; 200-225 fathoms; 29°13.5'N, 87°58.5'W. Holotype: USNM 96687 (dissected), from Gerda Station 448. Fig. la, b, c, d. Paratypes: USNM 96688 (Fig. If, dissected), 96689 (Fig. Ig), 96690 (Fig. le) from Gerda station 448. Diagnosis. •InXvoverX nearly equal in length to trunk; approximately 50 rows of closely apposed hooks on anteriormost introvert followed posteriorly by rows of more widely spaced hooks; most posterior rows incomplete dorsally. Tentacular crown dorsal to mouth, larger in proportion to body size than usual for Phascolosoma; X'X-ll digitiform tentacles. Exceptionally large mammillate papiUae with prominent apical protuberances; papUlae largest and most numerous at base of introvert and posterior trunk. Surface of papiUae covered with small, granular platelets, also scattered on non-papillary body surface. Longitudinal body wall musculature separated into anastomosing bundles. Four retractor muscles, dorsals arising in middle third of trunk, ventrals in posterior third; retractor muscles separate for most of length. Spindle muscle attached posteriorly at extremity of trunk and anteriorly immediately above anus. One fixing muscle, attaching lower esophagus to body wall in mid-trunk to left of ventral nerve cord. Intestinal coil with approximately 15 single coils. Contractile vessel simple. Nephridia attached nearly entire length to body wall; nephridiopores at approximate level of anus. Hooks sharply bent distally with clear streak close to convex surface; relatively narrow at base with basal rootlets on concave side. Description. •Trunk measurements average 6.7 mm (n = 80) in length for specimens from the Gerda collections and 12.8 mm (n = 14) for those from the M/V Oregon. The ranges for the two groups are, respectively, 3.5-11.4 mm and 7.417.3 mm. In two specimens, both from the Gerda collections, the introvert and tentacles are fully extended; in others the introvert is in varying states of conVOLUME 98, NUMBER 1 55 traction. One of the extended specimens has a total length of 12 mm (Holotype USNM 96687) and the other (Paratype USNM 96689) a total length of 17 mm. In the former the ratio of introvert to trunk is 1:1.4 and in the latter 1:1.1. In both specimens the relatively stout introvert is about one-half the maximum width of the trunk. The introvert is approximately one-third as wide as long; proportions are the same for the trunk. The short, thick, digitiform tentacles number 14 in the holotype and 22 in the paratype. They are arranged dorsal to the mouth in a circle that is interrupted at the mid-dorsal line by a heart-shaped nuchal organ. The color of the body of these preserved specimens is generally a pale grayish yellow, the posterior and anterior trunk being somewhat darker than the middle. The anterior introvert has a brownish appearance because of its dark-colored hooks. On the extended introvert of the holotype there are 70 rows of hooks. The first 25 rows are completely formed whereas those following may be incomplete dorsally (especially noticeable in rows 25 to 45). Following the first 52 rows in which the hooks are closely apposed, the individual hooks are more widely set apart. Scattered hooks are present after row 70, but no longer is there an obvious arrangement in rows. Hooks in the first 5 to 6 rows are light tannish yellow, whereas the remainder are dark brown. The most anterior 5 rows are smaller than those that follow, except for the farthest posterior ones which become increasingly smaller toward the posterior introvert. The form of the hook is simple (Figs, le, 2). The end is sharply curved, and, within the hook near the convex curvature a clear streak runs from base to apex gradually decreasing in width toward the apex. The hooks are best developed in rows 6 to 50. Measurements of hooks from rows 5 to 19 in paratype USNM 96690 show an average basal width of 0,044 mm and an average height of 0.051 mm. The basal processes number about 10 on each hook. Introvert papillae appear at regular intervals between the rows of hooks (Fig. 2). The body wall is rather thin, particularly in the mid-trunk region where the longitudinal muscle bands are visible through the integument. The most distinctive features of this species are the size and shape of the papillae at the anterior and posterior trunk (Figs, lb, c, d; 3). In these regions the papillae are numerous, concentrated, and mammillate in shape, each with a central protuberance bearing a pore. Most commonly the width and height are approximately equal although either one may exceed the other slightly. The largest papillae measure 0.16 x 0.16 mm in width and height in specimens from the Gerda collections which range in trunk length from 7 to 10 mm. Papillae of the somewhat larger specimens from the M/V Oregon collections, which range in trunk length from 17 to 18 mm, show a maximum width and height of 0.24 x 0.30 mm. In contracted specimens the base of the papillae may be constricted to form a naiTow stalk. Papillae in the midtrunk region are few, scattered and much flattened. The largest among them are the same diameter as the largest of the anterior and posterior papillae, but they have little or no elevation. Embedded in the integument of the papillae are small, well-separated platelets, ranging from colorless to light brown. Similar platelets are found scattered throughout the skin, although they are more concentrated on the papillae. The central protuberance of the papilla frequently appears brown. The bundles of the longitudinal musculature undergo considerable splitting and 56 PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON VOLUME 98, NUMBER 1 57 Figs. 2-3, Phascolosoma iurnerae: electron micrograph, scale = 20 /im); (scanning electron micrograph, scale = 2, (left) Rows of hooks from the anterior introvert (scanning 3, (right) Papillae of anterior trunk and posterior introvert