gill slit

Source-defined slit

Record the anatomical meaning supported by a reference and its applicability to the specimen.

1. What does gill slit denote in the anatomical terminology used for this taxon and life stage? definition
2. Which anatomical reference or specimen observation supports that interpretation? provenance

Aperture versus neighbours

Identify the aperture and establish whether nearby gills, folds, shared outlets or separately named openings belong to it.

1. Which tissue margins delimit this slit, and which adjacent structures belong to neighbouring models? boundary
2. Is this an individual branchial opening, a shared outlet, a spiracle or an unresolved aperture? definition

Connected compartments

Record both sides of the passage and distinguish observed continuity from anatomical inference.

1. Which compartments does this opening connect, and does it reach the external environment directly? boundary
2. Was continuity established by direct observation, imaging, dissection or a reference description? provenance

Position and count

Assign side and ordinal position using a declared counting convention.

1. How many openings are present on each side at the anatomical level being counted? measurement
2. Which landmarks and counting direction identify this slit across repeated observations? definition

Formation and persistence

Separate demonstrated perforation from an inferred developmental identity.

1. What evidence establishes an open passage rather than an unopened pouch or cleft? boundary
2. What stage-specific evidence supports interpreting its presence or absence as expected development? provenance

Conditioned dimensions

Record aperture size and shape alongside posture, ventilation phase and preparation effects.

1. What are the slit length, width and, where measurable, projected open area? measurement
2. How were posture, ventilation phase, viewing angle and preservation controlled or documented? provenance

Patency and flow

Distinguish aperture openness from directly observed movement of water through it.

1. Is the passage open, partly obstructed or occluded, and what observation supports that state? measurement
2. Was water passage observed, in which direction and under what ventilation conditions? measurement

Condition and follow-up

Record visible abnormalities, comparison evidence and the next investigation needed without assigning an unsupported cause.

1. How do the margins and aperture compare with neighbouring slits, the opposite side and a suitable reference? measurement
2. Which further observation or specialist assessment would resolve suspected obstruction, injury or developmental variation? action

Check these first

Recalled without web access and unsourced; every item is a lead to verify.

1. Which of these check these first hold for the sense of gill slit this model covers, and on what evidence? provenance

Kinds and varieties

Recalled without web access and unsourced; every item is a lead to verify.

1. Which of these kinds and varieties hold for the sense of gill slit this model covers, and on what evidence? provenance

Real-world use

Recalled without web access and unsourced; every item is a lead to verify.

1. Which of these real-world use hold for the sense of gill slit this model covers, and on what evidence? provenance

Typical measurements

Recalled without web access and unsourced; every item is a lead to verify.

1. Which of these typical measurements hold for the sense of gill slit this model covers, and on what evidence? provenance

Failure modes and hazards

Recalled without web access and unsourced; every item is a lead to verify.

1. Which of these failure modes and hazards hold for the sense of gill slit this model covers, and on what evidence? provenance

Neighbouring kinds and how to tell them apart

Recalled without web access and unsourced; every item is a lead to verify.

1. Which of these neighbouring kinds and how to tell them apart hold for the sense of gill slit this model covers, and on what evidence? provenance