In Cyclocosmia Ausserer, 87, a ctenizid spider with a highly modified abdomenIn Cyclocosmia Ausserer, 87,

In Cyclocosmia Ausserer, 87, a ctenizid spider with a highly modified abdomen
In Cyclocosmia Ausserer, 87, a ctenizid spider with a hugely modified abdomen (Zhu et al. 2006).Revision of Sternaspis Otto, 82 (Polychaeta, Sternaspidae)The sternaspid ventrocaudal shield is just not exposed and as such may have no direct defensive role, or only a slight one particular if any at all. Rather it might function as an anchoring device for the muscular bundles within the posterior physique region. PubMed ID:https://www.ncbi.nlm.nih.gov/pubmed/11836068 Having said that, combined together with the marginal chaetal bundles, they might kind a defensive structure to guard the ingestion on the posterior physique area. The presence of long spines as an antipredatory modification has been broadly documented inside the fossil record, among various benthic groups, like infaunal taxa (Brett and Fatostatin A Walker 2002, Walker and Brett 2002). A study by Wheeler (927) aids comprehend the connection in between muscle bundles and also the shape of your ventrocaudal shield; he concluded that the `form with the (ant’s) head and face is very largely determined by the size and shape of your flexor muscle tissues of the mandibles and in turn the functional or adaptative peculiarities of these organs are closely correlated together with the character of your flexor muscle tissues.’ He also showed that the head and face of a single species varies based on the relative size from the corresponding castes, but using the exception on the sexually active members, which are normally wasplike, the head and face of all castes of the identical species varies inside a certain pattern (Wheeler 927, figs 0, ). We think that a related pattern of muscular improvement must operate to modify the appearance in the ventrocaudal shield in sternapids, and that the variations found would fall within a consistent range such that it may be made use of to discriminate specimens into distinctive species.Systematics Order Sternaspida Dales, 962 Family members Sternaspidae Carus, 863 http:speciesid.netwikiSternaspidae Sort genus. Sternaspis Otto, 82. Diagnosis. Physique peanutshaped. Introvert with falcate, tapered or subdistally expanded hooks. Segments 7 constricted, with genital papillae protruding ventrally. Preshield region with 7 or eight segments. Ventrocaudal shield generally stiff, typically provided with radiating ribs and concentric lines, rarely versatile. Marginal shield chaetal fascicles involve lateral and posterior chaetae, often peg chaetae or extra delicate chaetae present. Branchiae coiled, abundant filaments, emerging from two lateral dorsal plates, near the anus, or directly from the body wall. More, thinner coiled interbranchial papillae present. Composition. 3 genera: Sternaspis, Caulleryaspis gen. n. and Petersenaspis gen. n. Remarks. Vejdovsk(882) published an incredibly thorough account on the anatomy, physiology and development of Sternaspis scutata; only some months later, Rietsch (882) published an equally thorough account of the same species. The reason Sternaspis was given a lot attention was probably because of the argument over the distinction between “Gephyrea” and Chaetopoda within Annelida, and that Sternaspis had attributes that pertained to both groups. In general, Sternaspis does resemble an echiuridKelly Sendall Sergio I. SalazarVallejo ZooKeys 286: 4 (203)in the exterior, even more so if one confuses the anterior finish with all the posterior, as was the case until corrected by Krohn (842). Vejdovsk(882) and Rietsch (882) outlined the affinities aligning Sternaspis with all the polychaetes and shortly afterwards Sternaspis was accepted as a polychaete (Dahl 955). The household was proposed by Carus (863:453).

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