III - Practical hints

I am in favor of pictorial identification and comparison of species: by direct comparison of specimens, or their photographs, or drawings. It is a natural approach, by which we recognize faces of people, it requires some initial experience, “training of taxonomist’s eyes”, but when that is acquired, it works faster that any highly scientific methods.
Recent progress in photography permits the recording of appearance and diagnostic details of Salticidae specimens, starting from alive, then preserved in ethyl alcohol, submerged or temporarily dried, to details of pedipalps, epigyne and internal structures of the cleared epigyne. Photograph can be stored on computer disks or on the Internet. While making such documentation is available to every photographer, or nature lover, the documentation for scientific purposes require only minimum precision in making, handling and retrieving from stores. For recognizing species we need general appearance photos in three standard positions (dorsal, lateral and frontal), photographs of detached palps (ventral and lateral view), photograph of epigyne in situ, and also cleared and examined in translucent light. Preferably, the spider should be photographed alive first, but if already collected then as soon as possible following preservation: for the first weeks after preservation the spider appears life-like, but within a few years the colors gradually fade. The best examples of photo-documentation are the plates of  species of Bornean Salticidae by P. Koomen, shown in this database, and the samples below:
Salticidae specimen, dorsal: alive and faded one after 30 years in alcohol
Frontal view: face - eyes & clypeus, palps, legs I. Lateral viev: profile of carapace, height, posterior slope; shape & proportions of abdomen. Chelicera: internal margin dentition.
Epigyne in situ and cleared in 10-20% solution of KOH, to show internal structures
Pedipals, ventral and lateral views: note bulbus, embolus, spermophor, tibial apophysis

(©Photographs by P. Koomen)
It has become common practice to dump large collections in Museums where they may be forgotten for decades, some specimens happen to be studied for the first time after 100 years of storage. It should be a moral duty of a collector to photograph collected specimens before they become faded.
Photographs can be replaced by drawings, which are even better because they also include some interpretation, but their preparation requires additional artistic skill.
Laboratory methods of handling specimens for making drawings, or photographs, are similar. Specimens are examined submerged in ethyl alcohol (75%), in a Petri dish, preferably under a stereomicroscope (100x to 200x magnification), illuminated by oblique beams of cool light, which model shapes by lights and shadows. The simplest method to immobilize specimens in the required position is to have the bottom of the dish covered by fine sand. The whole specimen, or its detached palpus, can be gently pressed into the sand, in the desired position. The epigyne can be photographed in situ, or separated from body and placed flat on a microscopic slide. The epigyne can be detached from the body by sliding the tip of a small scalpel under it, and cutting the tegument around the epigyne. For examination of internal structure the epigyne can be placed in COOL aqueous 10-20% solution of KOH for some 24 hours, and then stained in the very light alcohol solution of Chlorazol Black E for a short time.
Examination of the internal structures should be done using a compound microscope, with 10x to 40x objective. Photographs of such details are best made using a camera with an automatic timing device, attached to the phototube of the microscope To make drawings the best method is to place a “net micrometer” – a piece of glass with a fine grid of minute squares, inside the ocular of the microscope, and to draw the examined structures as seen in each square, on a sheet of paper with a grid drawn on it. Shading is best done on coquille paper using a soft pencil. The detached epigyne or palp should be stored in a minute vial, together with the whole specimen.
The traditional approach to identification of Salticidae consists of the progressive checking of hierarchically arranged characters.
Identification of species based on Simon's 1937 key begins by checking:
1. teeth on chelicerae (often requiring breaking of a chelicera)
2. length of pedicel;
3. presence or absence of tooth on retrolateral margin of chelicera;
4. presence of striae behind eyes III, as well as number and size of spines on legs;
5. "normal" shape of cephalothorax;
6. eyes II "distinctly" closer to eyes I than to eyes III;
7. eye field "slightly" narrowing anteriorly;
8. reading half a page long description of color pattern and setae;
9. checking 2 diagrammatized drawings purporting to illustrate several related species.
This may lead to discovery, in this example, that the examined specimen is a Sitticus, presumably S. floricola. The characters used are described vaguely with relative terms like: "longer", "slight", "distinct". I tried for 20 years to make precise descriptions with measurements - all in vain - the individual variability of specimens is too great to make that method useful for a large number of species. More useful is direct comparison with other identified specimens - whenever possible - type specimens (but frequent handling endanger type specimens), so access to larger collections seems necessary for taxonomic work, as well as access to a library of descriptions. In practice, after several repetitions of steps suggested by keys, a taxonomist memorizes the appearance of a particular taxon and later recognizes it at first glance. So why not shorten that process by providing an easier method of recognition? For example, by making a library of pictures of species, preferably photographs, both of type specimens (to protect them) and newly collected ones (for identification). This is the rationale behind the creation of the present database.